Flora and Phytochorology of Lahij Governorate of Yemen: 3-Systematic Revision of Malvaceae s.l. in Toor Al-Baha District

Al-Hawshabi, Othman S. S.; Osman, Ahmed K.; Abbas, Ahmed M.; AlQthanin, Rahmah N.; Badry, Mohamed O.

doi:10.3390/d17040242

Open AccessArticle

Flora and Phytochorology of Lahij Governorate of Yemen: 3-Systematic Revision of Malvaceae s.l. in Toor Al-Baha District

by

Othman S. S. Al-Hawshabi

^1,†

,

Ahmed K. Osman

²

,

Ahmed M. Abbas

^3,*

,

Rahmah N. AlQthanin

^3,4

and

Mohamed O. Badry

^2,*,†

¹

Biology Department, Faculty of Science, University of Aden, Khormaksar, Aden P.O. Box 6235, Yemen

²

Department of Botany and Microbiology, Faculty of Science, South Valley University, Qena 83523, Egypt

³

Department of Biology, College of Science, King Khalid University, Abha 61413, Saudi Arabia

⁴

Prince Sultan Bin Abdelaziz for Environmental Research and Natural Resources Sustainability Center, King Khalid University, Abha 61421, Saudi Arabia

^*

Authors to whom correspondence should be addressed.

^†

These authors contributed equally as co-first authors.

Diversity 2025, 17(4), 242; https://doi.org/10.3390/d17040242

Submission received: 4 February 2025 / Revised: 17 March 2025 / Accepted: 25 March 2025 / Published: 28 March 2025

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Abstract

:

This study presents a thorough revision of the Malvaceae s.l. (sensu lato) family within the Flora of the Toor Al-Baha District, Lahij Governorate, South Yemen. The documented taxa were subjected to morphological revision alongside an analysis of life forms and chorological affinities. Thirty taxa are categorized into 12 genera within four subfamilies. Each species is presented with its current classification, accepted names, synonyms (when applicable), vernacular names (when applicable), photographs, and distribution to aid in identifying and recognizing these species. The documented mallow species comprises 80% perennials and 20% annuals. Chamaephytes constituted the predominant life forms, comprising 50% of the total taxa surveyed. A phytogeographical analysis revealed that chorotypes with Sudano-Zambezian affinities are predominant, comprising 83.34% of the recorded mallows. The two subfamilies, Grewioideae and Sterculioideae, are distinguished by the lack of an epicalyx and the presence of an androgynophore, unlike the subfamilies Dombeyoideae and Malvoideae. The highest richness genera included Grewia, with seven taxa, and Hibiscus, Abutilon, and Corchorus, each comprising four species. The research presented nine artificial keys for wild mallows in the Lahij Governorate, comprising three for subfamilies and six for genera.

Keywords:

Dombeyoideae; Grewioideae; Sterculioideae; subfamilies; floristics; Toor Al-Baha; Yemen

1. Introduction

Malvaceae s.l. (sensu lato), commonly known as the mallow family, is a diverse group of plants that include herbs, subshrubs, shrubs, and little trees. It has 245 genera and 4300 to 4500 species occupying various habitats, from arid to aquatic and lowlands to high altitudes [1,2].

Yemen’s plant life remains mainly untouched and showcases unusual diversity and abundance. The richness in species is attributed to climatic changes in ancient times, which allowed numerous species to succeed in new ecological habitats [3]. Moreover, the vegetation shares similarities with tropical Africa, Sudanese, Saharo-Arabian regions, Mediterranean countries, and Irano-Turanian areas [4,5,6].

Malvaceae s.l. stands out as one of Yemen’s interesting plant groups, known for its importance and widespread presence, consisting of 25 genera and 112 species [7]. In 2017, Al-Hawshabi et al. [8] recorded 11 genera and 30 species from this family in the Toor Al-Baha area of Lahij Governorate, southwest Yemen.

In Yemen, many species of Malvaceae s.l. are cultivated as a source of fiber or human food, such as Abelmoschus esculentus (L.) Moench, Corchorus olitorius L., Gossypium spp., Hibiscus sabdariffa L., Thespesia populnea (L.) Sol. ex Corrêa, Grewia erythraea Schweinf. and Grewia tenax (Forssk.) Fiori. However, in the Toor Al-Baha district of the Lahij Governorate, a crucial hotspot for Yemeni plant variety, no thorough taxonomic research has examined the diversity of the mallow family. The earlier works focused on a small number of genera/or species as part of studies at the subfamily and generic levels or in describing specific species [9,10].

This study focuses on exploring the floristic diversity of Malvaceae in the Toor Al-Baha district. It aims to conduct a taxonomic reassessment of the genera and species within the family, highlighting key diagnostic morphological traits to differentiate between the genera and closely related species and provide keys to identify all the mallow species found in the region, serving as a valuable resource for researchers and students to understand better, conserve, and utilize these ecologically significant plants.

2. Materials and Methods

Mallow specimens have been collected from a region spanning 12°58′ to 13°20′ N and 44°11′ to 44°39′ E in the Toor Al-Baha district, Lahij Governorate, southwest Yemen, by the first Author (O. S. S. Al-Hawshabi) during six collecting trips within eight excursions conducted between July 2018 and July 2024 (Figure 1, Table 1).

The collected specimens were identified and named, and the classification and scientific names were updated following the existing literature [1,10,12,13,14,15,16,17,18]. For species with long list of synonyms, we have retained only the most relevant and widely recognized synonyms, mainly those mentioned in the flora books of Yemen.

The surveyed taxa’s growth forms, life form categories, and life spans were identified [1,19,20], and chorotypes were classified [21]. Specimens were dried and preserved as voucher samples, then deposited in the herbarium of the Biology Department, Faculty of Education, Aden University, Yemen.

3. Results

3.1. Floristic Composition

A total of 30 species belonging to 12 genera of the four subfamilies (Dombeyoideae, Grewioideae, Malvoideae, and Sterculioideae) of Malvaceae s.l. were recorded from the study area (Table 1). Among these, the genus Grewia L. had the highest richness, with seven species (23.3% of total species). This was followed by Hibiscus L., Abutilon Mill. and Corchorus L. with four species each (13.3%), while Pavonia Cav. accounted for three species (10%).

The surveyed mallow plants included 24 perennials (80%) and 6 annuals (20%), classified into four types of growth forms and represented by 1 tree (3.34%), 12 shrubs (40%), 7 subshrubs (23.3%), and 10 herbaceous (33.33%) species of plants (Table 1).

3.2. Life Form Spectra

The mallow species surveyed in the study area are classified into three life form classes according to POWO [1], Al-Hawshabi et al. [9], Hassib [20], and Raunkiaer [21]. Chamaephytes were the most frequent life form (15 species = 50%), followed by Phanerophytes (9 species = 30%) and Therophytes, which were represented by six species (20%) (Table 1).

3.3. Chorological Affinities

The chorological analysis of the surveyed mallow flora categorized the 30 recorded plant species into three main phytogeographical groups: monoregional, biregional, and pluriregional. The monoregional chorotype (pure Sudano-Zambezian) consists of five species, representing 16.68% of the total taxa in the study area. The biregional elements constituted the highest representation among the species surveyed in the study area, accounting for 10 species (33.35%). Within this group, two primary chorotypes were identified chorotypes: the Saharo-Sindian/Sudano-Zambezian elements, which encompass the most significant proportion of species (eight species), accounting for 26.68% of the total mallow species surveyed, and the Sino-Japanese/Sudano-Zambezian elements, represented by two species (6.67%). A total of ten species (33.33%) of varying affinities represented the pluriregional elements. Two species exhibit a Pantropical distribution, representing 6.67% of the total taxa. The other three species were categorized within Neotropical, Palaeotropical, and Tropical chorotypes, represented by one species each (3.33%) (Figure 2, Table 1).

3.4. Artificial Dichotomous Key for Identifying Subfamilies of the Malvaceae s.l. Family Recorded in Toor Al-Baha District, Lahij Governorate

1a. Epicalyx absent; androgynophore present ………………………………….…………… 2
1b. Epicalyx usually present; androgynophore absent …………………….……………….. 3
2a. Flowers polygamous, petals absent …………………………………… 4. Sterculioideae
2b. Flowers hermaphrodite, petals present ………………………………… 2. Grewioideae
3a. Sepals free; stamens 10 free ……………………………………………. 1. Dombeyoideae
3b. Sepals fused at base; stamens numerous, Monadelphous ………...…… 3. Malvoideae

3.4.1. Subfamily: Dombeyoideae Beilschm. in Flora 16 (2): 86, 106 (1833)

Shrubs or herbs with stellate indumentum. Leaves simple, sometimes cordate and/or palmatilobed or rarely dissected. Flowers in axillary cymes or solitary on indeterminate shoots; epicalyx bracts present; sepals basally fused to almost free; petals, often asymmetric, sometimes persistent; androgynophore absent; stamens usually forming a staminal tube, more rarely nearly free, anthers on distinct, partly free filaments, not monothecal, staminodes usually present; ovary 5-locular, locules 1- to many-ovulate, style usually with apical style branches. Fruits are usually capsular, thick, and woody to coriaceous or thin; seed coat glabrous [22].

One genus, with one species, was recorded in the study area.

1.: Melhania Forssk. in Fl. Aegypt.-Arab.: 64 (1775); TYPE: Melhania velutina Forssk.

(1): M. muricata Balf.f. in Proc. Roy. Soc. Edinburgh 11: 503 (1882); Type: Yemen, Road from Ghubbah to hadiboh, pass east of Hadiboh., 3-II-1990, A. G. Miller, M. Bazar’a, L. Guarino., N. Kassim, M10266 (Holotype: E00033992!)

Heterotypic Synonym

Melhania parvifolia Chiov. in Fl. Somala 1: 103 (1929)

Perennial herb, or subshrub, leaves usually ovate-oblong to lanceolate, truncate rounded at the apex, with serrate-crenate margins. Flowers are solitary or rarely in two-flowered cymes, epicalyx bracts cordate, and enlarging in fruit. Capsule subglobose. Seeds grey, strongly muricate. Grows on exposed limestone hills, rocky foothills, sand over limestone, and rocky or stony slopes on altitudes 422–1026 m above sea level (Figure 3A).

3.4.2. Subfamily: Grewioideae Dippel in Handbuch der Laubholzkunde 3: 56–57 (1893)

Trees or shrubs, rarely herbs. Leaves are usually simple, rarely lobed. Inflorescences terminal or leaf-opposed, sometimes paniculate; flowers with epicalyx. Sepals distinct or nearly so, lacking ventral nectaries; androgynophore present; stamens numerous, distinct; outermost stamens sometimes sterile; anthers dithecal, dorsifixed. Fruit usually a capsule or drupe, 2–4-lobed; seeds typically glabrous, rarely winged [22].

Two genera and eleven species were recorded in the study area.

Artificial dichotomous key to the genera of Grewioideae recorded in Toor Al-Baha district, Lahij Governorate.

1a. Herbs, rarely undershrubs; petals not clawed; fruit a capsule ………...… 1. Corchorus
1b. Tree or shrubs; petals clawed, fruit a drupe …………………………………... 2. Grewia

Corchorus L. in Sp. Pl.: 530 (1753); LECTOTYPE: Corchorus olitorius L., designated by N. L. Britton et Millspaugh, Bahama Fl. 262 (1929)

The genus is represented by four species widely distributed in the study area (Figure 4). The key below distinguishes between them [10]:

1a. Stems prostrate; leaf blades < 2 cm long ……………………………….… 1. C. depressus
1b. Stems erect to ascending; leaf blades 4–8 cm long ……...………………..……....……... 2
2a. Stamens numerous; capsule terminated by undivided beak at the apex ….…….…… 3
2b. Stamens 10; capsule terminated by 3 spreading bifid tips at the apex …... 3. C. tridens
3a. Stem glabrous; capsule 5-valved ……………………………………….….. 2. C. olitorius
3b. Stem with short, crisped hairs; capsule 3-valved …………………..…. 4. C. trilocularis

(1): C. depressus (L.) Peterm. in Pflanzenreich: 924 (1845)

Homotypic Synonyms

Antichorus depressus L. in Mant. Pl. 1: 64 (1767)

Corchorus antichorus Raeusch. in Nomencl. Bot. Pl. Illustr., ed. 3: 158 (1797), nom. illeg.

Heterotypic Synonyms

Corchorus microphyllus Fresen. in Mus. Senckenberg. 2: 156 (1837)

Jussiaea edulis Forssk. in Fl. Aegypt.-Arab.: 210 (1775)

Perennial herbs, elliptic to broadly elliptic, margins irregularly crenate, absence of auricles, apex acute-obtuse. Flowers axillary, usually 1–2 opposite the leaves. Capsule 4-valved, curved or straight, ending with three beaks, usually buried in the soil. Seeds oblong, brown, glabrous. Grow on fields in clay, silt soils, wadies, and soils mixed with gravel and waste ground. At altitudes between 314 and 653 m above sea level.

(2): C. olitorius L. in Sp. Pl.: 529 (1753)

Heterotypic Synonyms

Corchorus catharticus Blanco in Fl. Filip.: 442 (1837)

Corchorus decemangularis Roxb. ex G.Don in Gen. Hist. 1: 544 (1831)

Corchorus lanceolatus G.Don in Gen. Hist. 1: 543 (1831)

Corchorus longicarpus G.Don in Gen. Hist. 1: 543 (1831)

Corchorus malchairii De Wild. in Études Fl. Bangala & Ubangi: 345 (1911)

Corchorus olitorius var. australiensis Domin in Biblioth. Bot. 22 (89): 380 (1927)

Corchorus olitorius var. grandifolius De Wild. in Ann. Mus. Congo Belge, Bot., sér. 5, 2: 45 (1908)

Corchorus olitorius var. incisifolius Asch. & Schweinf. in Mém. Inst. Égypt. 2: 53 (1887)

Corchorus olitorius var. malchairii (De Wild.) R.Wilczek in Fl. Congo Belge 10: 86 (1963)

Corchorus quinquelocularis Moench in Methodus: 248 (1794)

Annual herb. Leaves ovate-lanceolate, elliptic, or oblong-ovate. Inflorescence 1–2-flowered cymes, ensiform, caudate at the apex. Capsules 5-valved. Seeds triangular, greenish black. Cultivated in clay soils at 717 m above sea level.

(3): C. tridens L. in Mant. Pl. 2: 566 (1771)

Heterotypic Synonyms

Corchorus burmanni DC. in Prodr. 1: 505 (1824)

Corchorus senegalensis Juss. ex Steud. in Nomencl. Bot., ed. 2, 1: 417 (1840)

Annual herbs, leaves oblong-lanceolate to linear-lanceolate or somewhat elliptic-obovate, margin serrate or serrate-crenate, base obtuse, apex cute. Inflorescence 1–4-flowered cymes. Capsules 3-valved. Seeds angular, oblong, dull dark brown to black. Grow in fields, sandy soils, slopes, and abundant weeds in fields where sorghum plants are cultivated and on the edges of wadis. At altitudes between 704 and 841 m above sea level.

(4): C. trilocularis L. in Mant. Pl. 1: 77 (1767)

Heterotypic Synonyms

Corchorus asplenifolius E.Mey. ex Harv. & Sond. in W.H.Harvey & auct. suc. (eds.), Fl. Cap. 1: 229 (1860), not validly publ.

Corchorus gracilis R.Br. in H.Salt, Voy. Abyss., App. 4: 65 (1814), nom. nud.

Corchorus serrifolius DC. in Prodr. 1: 504 (1824), nom. illeg.

Corchorus somalicus Gand. in Bull. Soc. Bot. France 69: 348 (1922)

Corchorus triflorus Bojer in Rapp. Annuel Trav. Soc. Hist. Nat. île Maurice 12: 17 (1842)

Annual or perennial herbs, leaves oblong-lanceolate to ovate-elliptic, base obtuse or broadly cuneate, apex acute or somewhat rounded. Inflorescence 1–3-flowered cymes opposite the leaves. Capsules 3-valved. Seeds oblong-ovoid, gray to black. Grow in clay, silt, sandy soils, and slopes. It is an abundant weed of fields where sorghum plants are cultivated in the Rocky Mountains, on altitudes between 299 and 981 m above sea level.

2.: Grewia L. in Sp. Pl.: 964 (1753); LECTOTYPE: Grewia occidentalis L. (1753), designated by M. L. Green, Prop. Brit. Bot. 186 (1929).

Widely distributed in the study area, seven species are recorded from the study area, and all of them are considered native (Figure 5).

The artificial dichotomous key below distinguishes between Grewia recorded in Toor Al-Baha district, Lahij Governorate:

1a. Petals white; fruit 2–4 lobed ……………………………..……..………………………... 2
1b. Petals yellow; fruit 1–2 lobed ………………………………………………………….… 4
2a. Inflorescences in cymes, three-flowered; filaments pink ……..….................................................................................… 4. G. tembensis var. ellenbeckii
2b. Inflorescences axillary, flower solitary; filaments white ………………..……………... 3
3a. Petioles 3–7 mm long; leaf-blade ovate to obovate, with serrate margin; fruit with stellate hairs ……………………………...…………….….………….……..… 2. G. erythraea
3b. Petioles 0.8–1.7 cm long; leaf-blade rounded to ovate, with crenate to serrate margin; fruit glabrous ……………………………………………………………..…………. 5. G. tenax
4a. Leaf margins shallowly dentate to ± entire, upper surface leaf-blade dark shiny green and glabrous ……………………………………………………………………… 1. G. arborea
4b. Leaf margins crenate to ± serrate, upper surface leaf-blade green and very shortly stellate hairy ………………………………………………………………………………….… 5
5a. Petioles 3–4 mm long; fruit when ripe red color …………………..………. 6. G. tristis
5b. Petioles 5–9 mm long; fruit when ripe black color …………………………...……….... 6
6a. Both leaf surfaces are scabrid with stellate hair; all flowers having 4 red bracts …………………………………………………………………….……….. 3. G. schweinfurthii
6b. Both leaf surfaces are covered with tomentose hairs; the flowers without bracts ……………………………………………………………………………………... 7. G. velutina

(1): G. arborea (Forssk.) Lam. in Encycl. 3: 45 (1789)

Homotypic Synonym

Chadara arborea Forssk. in Fl. Aegypt.-Arab.: 105 (1775)

Heterotypic Synonym

Grewia fallax K.Schum. in Bot. Jahrb. Syst. 15: 116 (1892)

Small tree leaves oblong to obovate, margins serrate, apex obtuse to sub-acute, base unequal, rounded. Inflorescence 1–3-flowered axillary cymes. Fruit 2-lobed, puberulent stellate. A rare plant in the study area grows on slopes and rocky hills at altitudes between 1257 and 1301 m above sea level.

(2): G. erythraea Schweinf. in Verh. K. K. Zool.-Bot. Ges. Wien 18: 671 (1868)

Homotypic Synonym

Grewia tenax var. erythraea (Schweinf.) Chiov. in Fl. Somala 2: 35 (1932)

Much-branched shrub leaves obovate to elliptic, margins dentate, apex rounded to obtuse, base cuneate to rounded. Inflorescence solitary in the leaf axils. Fruit 4-lobed, glabrous or stellate hairy. Grows on the escarpment, limestone rocky, and in stony soils on altitudes between 387 and 1095 m above sea level.

(3): G. schweinfurthii Burret in Bot. Jahrb. Syst. 45: 173 (1910)

Homotypic Synonyms

Vincentia schweinfurthii (Burret) Burret in Notizbl. Bot. Gart. Berlin-Dahlem 9: 735 (1926)

Vinticena schweinfurthii (Burret) Burret in Notizbl. Bot. Gart. Berlin-Dahlem 12: 715 (1935)

Shrub. Leaves elliptic to rhomboid, margin serrate, apex acute, base rounded to broadly cuneate. Inflorescence 2–3-flowered axillary cyme. Fruit unlobed, globose, black, thinly pilose. Grows on steep limestone slopes, rocky hillsides, and sandy soils on altitudes between 752 and 841 m above sea level.

(4): G. tembensis Fresen. var. ellenbeckii Burret in Bot. Jahrb. Syst. 45: 194 (1910)

Heterotypic Synonyms

Grewia membranacea A.Rich. in Tent. Fl. Abyss. 1: 90 (1848)

Grewia parvifolia Hochst. ex A.Rich. in Tent. Fl. Abyss. 1: 91 (1848)

Shrub. Leaves elliptic to round, obtuse, margin serrate, rounded to subcordate base, with densely white-felted below. Inflorescence 2–3-flowered axillary cyme. Fruit 4-lobed, glabrous, red when mature. Growing on hillsides at 1095 m above sea level.

(5): G. tenax (Forssk.) Fiori in Agric. Colon. 5 (Suppl.): 23 (1911 publ. 1912)

Homotypic Synonym

Chadara tenax Forssk. in Fl. Aegypt.-Arab.: 105 (1775)

Much-branched shrub. Leaves orbicular, margin coarsely crenate, entirely glabrous. Flowers solitary in the leaf axils. Fruit 4-lobed, entirely glabrous. Widely distributed in the study area, it grows on a stony plain, limestone slopes, rocky ground, alluvial sandy plain, and the foothills of the escarpment at altitudes between 386 and 762 m above sea level.

(6): G. tristis K.Schum. in Bot. Jahrb. Syst. 15: 116 (1892)

Much-branched shrub. Leaves elliptic, margins coarsely serrate, apex obtuse to rounded, base equal, rounded to subcordate. Flowers solitary or paired 1–3-flowered axillary cyme. Fruit 1–2-lobed, tomentose, red at mature. Grows on exposed scrubby hillside in the gorge of the Wadi on altitudes between 820 and 873 m above sea level.

(7): G. velutina (Forssk.) Lam. in Encycl. 3: 45 (1789)

Homotypic Synonym

Chadara velutina Forssk. in Fl. Aegypt.-Arab.: 105 (1775)

Heterotypic Synonym

Grewia canescens A.Rich. in Tent. Fl. Abyss. 1: 86 (1848)

Much-branched shrub. Leaves obovate to rhomboid margin coarsely serrate, apex acute, base somewhat unequal, rounded. Flowers 1–3-flowered axillary cymes. Fruit unlobed, brown to black when mature, tomentose. Grows along the escarpment, granite, limestone, and good rainfall at altitudes between 820 and 1257 m above sea level.

3.4.3. Subfamily: Malvoideae Burnett in Outlines of Botany 816: 1094-1118 (1835)

Herbs, shrubs, or trees; often stellate-hairy, sometimes spiny. Leaves usually stipulate, simple or lobed, sometimes with nectaries on dorsal veins. Flowers perfect, solitary or in cymes, forming spicate to paniculate or head-like inflorescences; epicalyx present or absent; calyx gamosepalous, valvate; corolla regular to slightly irregular; petals 5, adnate to staminal column; stamens monadelphous; anthers reniform, 1-celled; style with lobed or branched stigmas; carpels (1-)3 to many, axile placentation. Fruit a dehiscent capsule or schizocarp with mericarps. Seeds reniform, trigonous, or turbinate [22].

Eight genera and 17 species, among them 8 species belonging to Abutilon and Hibiscus.

Artificial dichotomous key to the genera of Malvoideae recorded in Toor Al-Baha district, Lahij Governorate

1a. Fruit a schizocarp of indehiscent mericarps …………………………………………… 2
1b. Fruit a capsule ……………………………………………..……………………………… 5
2a. Epicalyx bracts present ………………………………………………..………………….. 3
2b. Epicalyx bracts absent ………………………………………………..…..……………….. 4
3a. Epicalyx bracts usually 3; number of stigmas equal to the number of carpels …………………………………………………………………………………… 5. Malvastrum
3b. Epicalyx bracts 5 or more; number of stigmas double number of carpels …………..…………………………………………………………………………….. 6. Pavonia
4a. Calyx ribbed at the base; fruit ˂1 cm in diameter; mericarp one-seeded, splitting basally………………………………………………………………………………………... 8. Sida
4b. Calyx not ribbed at the base; fruit ≥1 cm in diameter; mericarp 2–3 seeded, dehiscent dorsally ………………………………………………………………………..…… 1. Abutilon
5a. Calyx glandular; style simple; seeds wooly …………………………………………… 6
5b. Calyx non-glandular; style 5-branched; seeds not wooly ..………………..…………. 7
6a. Epicalyx bracts 3 in number; cordate in shape ………………………….. 3. Gossypium
6b. Epicalyx bracts 9 in number, filiform ………...………...………………. 2. Cienfuegosia
7a. Epicalyx bracts 3 in number, broadly ovate to cordate ………………...……… 7. Senra
7b. Epicalyx bracts 5 or more in number, filiform in shape …………..……….. 4. Hibiscus

1.: Abutilon Mill. in Gard. Dict. Abr., ed. 4.: [s.p.] (1754); LECTOTYPE: Abutilon theophrasti Medik., designated by Shuttleworth ex Gray, Pl. Wright. 1: 21 (1852).

Widely distributed in the study area, four species are recorded from the study area, all native. The next artificial dichotomous key distinguishes them (Figure 6):

1a. Mericarps usually 10 in number ………..……………………..………... 2. A. fruticosum
1b. Mericarps 14 or more in number …………………………………………………………. 2
2a. Mericarps 14–18 in number, each mericarp with two awns; seeds papillose ….…….. 3
2b. Mericarps 30 in number, rounded; seeds with stellate hairs ……………………………………………………………….... 4. A. pannosum var. figarianum
3a. Basal leaves with leafy stipules; mericarps 18 in number, acute ………………………………………………………………………..… 3. A. hirtum var. hirtum
3b. Basal leaves with filiform stipules; mericarps usually 14 in number with two awns ………………………...……………………………………………..……..…... 1. A. bidentatum

(1): A. bidentatum (Hochst) A.Rich. in Tent. Fl. Abyss. 1: 68 (1848)

Homotypic Synonym

Sida bidentata Hochst in Exsicc. (Pl. Schimp.) 1842: n. 1003 (1842)

Heterotypic Synonym

Abutilon microcarpum Mattei in Boll. Reale Orto Bot. Palermo, n.s., 1: 90 (1915)

Woody perennial herbs. Leaves ovate, margins coarsely dentate, acute with a cordate base. Flowers orange-yellow, solitary, or paired in the leaf axils or small leafy axillary panicles. Mericarps about 15, acute. Seeds brown to black. Grow on the escarpment and alluvial plains. They are also found in the roadsides, field borders, and thorn fences around fields and houses on altitudes between 656 and 1160 m above sea level.

(2): A. fruticosum Guill. & Perr. in Fl. Seneg. Tent.: 70 (1831)

Homotypic Synonyms

Abutilon albidum subsp. fruticosum (Guill. & Perr.) Maire in Mém. Soc. Hist. Nat. Afrique N. 3: 154 (1933)

Sida perrottetiana D.Dietr. in Syn. Plant. 4: 855 (1846)

Perennial herb. Leaves ovate, cordate based, apex obtuse to rounded, margin denticulate. Flowers yellow, usually solitary in the leaf axils. Mericarps 10, acute. Seeds brown. Grows on sandy or rocky ground, alluvial soils, stony hills, foothills, and rain-shadow areas on altitudes between 509 and 1160 m above sea level.

(3): A. hirtum (Lam.) Sweet in Hort. Brit.: 53 (1826) var. hirtum

Heterotypic Synonyms

Abutilon graveolens (Roxb. ex Hornem.) Wight & Arn. in R.Wight, Cat. Ind. Pl.: 13 (1833)

Abutilon graveolens var. queenslandicum Domin in Biblioth. Bot. 22 (89): 952 (1928)

Abutilon hirtum var. heterotrichum (Hochst. ex Mattei) Cufod. in Bull. Jard. Bot. Natl. Belg. 39 (Suppl.): XXVIII (1969)

Abutilon lugardii Hochr. & Schinz in Bull. Herb. Boissier, sér. 2, 3: 82 (1903)

Sida graveolens Roxb. ex Hornem. in Hort. Bot. Hafn., Suppl.: 77 (1819)

Perennial herb. Leaves cordate, margins doubly serrate, apex acuminate, base cordate. Flowers solitary, in the leaf axils. Mericarps 18, acute. Seeds brown to black. Grows on sandy, stony, and alluvial soils at altitudes between 675 and 760 m above sea level.

(4): A. pannosum var. figarianum (Webb) Verdc. in Fl. Trop. E. Africa, Malv.: 124 (2009)

Homotypic Synonym

Abutilon figarianum Webb in Fragm. Fl. Aethiop.-Aegypt.: 52 (1854)

Heterotypic Synonyms

Abutilon impressum Hochst. ex Mattei in Boll. Reale Orto Bot. Palermo, n.s., 1: 95 (1915)

Abutilon webbianum Mattei in Boll. Reale Orto Bot. Palermo, n.s., 1: 6 (1915)

Subshrub. Leaves ovate to cordate, margins dentate, apex acuminate, base cordate. Flowers axillary in the leaf axils. Mericarps 30, rounded stellate. Seeds brown. Grows on roadsides, silt plains, villages, alluvial plains, field borders, and borders wadis on altitudes between 303 and 781 m above sea level.

2.: Cienfuegosia Cav. in Diss. 3: 174 (1787); TYPE: Senegal. Cienfuegosia digitata Cav. in Diss. Bot. 3: 174, t. 72 Figure 2 (1787), D. Adanson s.n.
(1): C. welshii (T.Anderson) Garcke in Jahrb. Königl. Bot. Gart. Berlin 2: 337 (1883)

Homotypic Synonym

Hibiscus welshii T.Anderson in J. Proc. Linn. Soc., Bot. 5 (Suppl. 1): 8 (1860)

Heterotypic Synonyms

Cienfuegosia chiarugii Chiov. in Fl. Somala 1: 101 (1929)

Cienfuegosia hearnii Fryxell in Brittonia 19: 33 (1967)

Cienfuegosia somaliana Fryxell in Brittonia 19: 33 (1967)

Subshrub. Leaves reniform to cuneate-ovate, entire to deeply 3-lobed. Flowers solitary or rarely paired in leaf axils. Capsule 3-lobed, hirsute glandular. Seeds hairy, wooly long. Grows on slopes and stony ground within Vachellia edgeworthii or Commiphora myrrha, it grows at altitudes between 422 and 760 m above sea level (Figure 3B).

3.: Gossypium L. in Sp. Pl.: 693 (1753); LECTOTYPE: Gossypium arboreum L., designated by Britton & Millspaugh, Bahama Fl. 273 (1920)
(1): G. arboreum L. in Sp. Pl.: 693 (1753)

Heterotypic Synonyms

Gossypium arboreum subsp. cernuum (Tod.) Roberty in Candollea 7: 318 (1937)

Gossypium arboreum var. indicum (Lam.) Roberty in Candollea 13: 43 (1950)

Gossypium arboreum var. obtusifolium (Roxb. ex G.Don) Roberty in Candollea 13: 38 (1950)

Gossypium arboreum subsp. sanguineum (Hassk.) Roberty in Candollea 7: 318 (1937)

Gossypium rubicundum Roxb. ex Wight & Arn. in Prodr. Fl. Ind. Orient. 1: 55 (1834)

Gossypium rubrum Forssk. in Fl. Aegypt.-Arab.: 88 (1775)

Gossypium soudanense (G.Watt) G.Watt in Bull. Misc. Inform. Kew 1926: 201 (1926)

Much-branched shrubs, naturalized, leaves palmately lobed, palmatipartite, margins lobed, base cordate, apex apiculate. Flowers solitary, in the leaf axils, epicalyx cordate. Capsule conical, gradually tapering to the apex, densely pitted with conspicuous glands. Seeds with long white hairs. Grow around fields in clay soils on altitudes between 642 and 684 m above sea level (Figure 3C).

4.: Hibiscus L. in Sp. Pl.: 693 (1753), nom. cons.; LECTOTYPE: Hibiscus syriacus L. (typ. conserv.; Taxon 15:43 [1966] and 17:44–47 [1968]).

Widely distributed in the study area, four species are recorded from the study area. The key below distinguishes between them (Figure 3D–G):

1a. Epicalyx bracts equaling the calyx in length; petals bright crimson with bright crimson central base ……………………..…..………………………………………... 1. H. deflersii
1b. Epicalyx bracts shorter than or equal to the calyx; petals yellow with pale to deep purple central base ………………………………………………………………………..…………….………….…. 2
2a. Mid-stem and distal leaves shallowly 3–5-palmately lobed; fruit capsule, 5-winged …………………………………………………………..……………………….... 4. H. vitifolius
2b. Mid-stem and distal leaves palmately parted; fruit capsule, acute ……………….…... 3
3a. Calyx inflated in fruit, membranous, lobes broadly triangular; fruit black, hispid, valves acuminate ……………….………………………………………………... 3. H. trionum
3b. Calyx not inflated in fruit, sub-membranous, linear-lanceolate; fruit brown, hispid, its valves with its awns hispid ……………………………….……………..… 2. H. palmatus

(1): H. deflersii Schweinf. ex Cufod. in Ann. Naturhist. Mus. Wien 56: 36 (1948)

Heterotypic Synonym

Hibiscus hansalii Cufod. in Ann. Naturhist. Mus. Wien 56: 42 (1948)

Subshrub. Leaves orbicular to ovate, coarsely dentate margins. Flowers solitary, crimson. Fruit capsule, globose, puberulous. Seeds wooly. A widely distributed plant in the study area grows on scrubby hills, the escarpment, roadsides, stony hills, mountain slopes, and round fields on altitudes between 490 and 1301 m above sea level.

(2): H. palmatus Forssk. in Fl. Aegypt.-Arab.: 126 (1775)

Heterotypic Synonyms

Hibiscus aristaevalvis Garcke in Bot. Zeitung (Berlin) 7: 849 (1849)

Hibiscus djabinianus Parsa in Kew Bull. 2: 18 (1947)

Hibiscus intermedius var. aristaevalvis (Garcke) Hochr. in Annuaire Conserv. Jard. Bot. Genève 4: 94 (1900)

Hibiscus richardii I.Riedl in Fl. Iranica 120: 31 (1976)

Annual herb. Leaves deeply palmately lobed, Flowers solitary, pale yellow with dark center. Capsule subglobos, sparsely pubescent. Seeds shiny black with a few appressed hairs. Grows as a weed on field borders, tracksides, and alluvial soils on altitudes between 691 and 829 m above sea level.

(3): H. trionum L. in Sp. Pl.: 697 (1753)

Homotypic Synonyms

Ketmia trionum (L.) Scop. in Fl. Carniol., ed. 2, 2: 44 (1771)

Ketmia vesicaria F.Lestib. in Botanogr. Belg.: 43 (1781), nom. superfl.

Trionum trionum (L.) Wooton & Standl. in Contr. U.S. Natl. Herb. 19: 417 (1915), not validly publ.

Heterotypic Synonyms

Hibiscus africanus Mill. in Gard. Dict., ed. 8.: n. 20 (1768)

Hibiscus ternatus Cav. in Diss. 3: 172 (1787)

Hibiscus trionicus St.-Lag. in Ann. Soc. Linn. Lyon 7: 127 (1880), orth. var.

Trionum annuum Medik. in Malvenfam.: 47 (1787)

Trionum cordifolium Moench in Suppl. Meth.: 202 (1802)

Trionum diffusum Moench in Methodus: 618 (1794)

Trionum frutescens Medik. in Malvenfam.: 47 (1787)

Annual herb. Leaves palmately 3–5-lobed, palmatisect. Flowers solitary in the leaf axils, yellow with a dark center. Capsule subglobose, hispid, enclosed by the inflated calyx. Seeds sub-obovate, black, muricate. Grows as a weed of cultivation on altitudes between 694 and 802 m above sea level.

(4): H. vitifolius L. in Sp. Pl.: 696 (1753)

Homotypic Synonyms

Abelmoschus vitifolius (L.) Wall. ex Hassk. in Cat. Hort. Bot. Bogor. Alt.: 198 (1844)

Fioria vitifolia (L.) Mattei in Boll. Reale Orto Bot. Palermo, n.s., 2: 72 (1917)

Perennial herb. Leaves palmately, 3–5 lobed, palmatifid. Flowers solitary in the leaf axils, large, yellow with a maroon center. Capsule subglobose, hispid valves, winged. Seeds reniform, black, muricate. Grows on escarpment, high plateaus, roadsides, villages, in thorn fences around fields, and rocky hillsides on altitudes between 485 and 1241 m above sea level.

5.: Malvastrum A. Gray in Mem. Amer. Acad. Arts, n.s., 4: 21 (1849); TYPE: Malvastrum wrightii A. Gray, C. Wright s.n. (LECTOTYPE: GH00052933!)
(1): M. coromandelianum (L.) Garcke in Bonplandia (Hannover) 5: 297 (1857)

Homotypic Synonyms

Malva coromandeliana L. in Sp. Pl.: 687 (1753)

Malva tricuspidata R.Br. in W.T.Aiton, Hortus Kew. 4: 210 (1812), nom. superfl.

Malvastrum tricuspidatum A.Gray in Smithsonian Contr. Knowl. 3 (5): 16 (1852), nom. superfl.

Malveopsis coromandeliana (L.) Morong in Ann. New York Acad. Sci. 7: 55 (1892)

Annual herb. Leaves ovate, unlobed, strongly dentate, apex acute, base cuneate. Flowers in axillary and terminal clusters, 4-flowered. Mericarps 10–12, pilose. Seeds smooth, brown to black, sub-obovate. Grows on fields and edges of roadsides at altitudes between 675 and 685 m above sea level (Figure 3K).

6.: Pavonia Cav. in Diss. 2 (App.): 2 (1786), nom. cons.; LECTOTYPE: Pavonia paniculata Cav. LT designated by?, Taxon 8: 310 (1959)

The genus is represented by three species recorded from the study area. The key below distinguishes between them (Figure 3I,J):

1a. Epicalyx bracts 14 in number, filiform; petals pink ………………………. 1. P. arabica
1b. Epicalyx bracts 5–6 in number, lanceolate to ovate; petals yellow to orange ……….. 2
2a. Petals yellow to orange, with dark purple central base; staminal tube glabrous ……………………………………………………………………………...…. 3. P. procumbens
2b. Petals yellow, without dark purple central base; staminal tube covered stellate hairs …………………………………………………………………………………… 2. P. burchellii

(1): P. arabica Hochst. & Steud. ex Boiss. in Fl. Orient. 1: 837 (1867)

Homotypic Synonym

Malache arabica (Hochst. ex Steud.) Kuntze in Revis. Gen. Pl. 1: 70 (1891)

Heterotypic Synonyms

Hibiscus flavus Forssk. in Fl. Aegypt.-Arab.: 126 (1775)

Pavonia arabica var. flavovelutina Ulbr. in Bot. Jahrb. Syst. 57: 161 (1921)

Pavonia arabica var. glanduligera Ulbr. in Bot. Jahrb. Syst. 57: 162 (1921)

Pavonia erlangeri Ulbr. in Bot. Jahrb. Syst. 57: 164 (1921)

Pavonia erythraeae Chiov. in Ann. Bot. (Rome) 13: 400 (1915)

Pavonia franchetiana Schinz in Bull. Herb. Boissier 3: 407 (1895)

Pavonia glandulosa Franch. in Sert. Somal.: 18 (1882), nom. illeg.

Pavonia pseudoarabica Mattei in Res. Sci. Somalia Ital. 1: 30 (1916)

Annual herb. Leaves unlobed, ovate to elliptic, the margin entire, base cordate, apex truncate. Flowers solitary in leaf axils or in small axillary cymes, pink. Mericarps 5, villous, unwinged. Seeds brown, truncate, with white hispid. It is a rare plant in the study area that grows on stony hills and rocky plains in the escarpment foothills on altitudes between 770 and 981 m above sea level.

(2): P. burchellii (DC.) R.A.Dyer in Bull. Misc. Inform. Kew 1932: 152 (1932)

Homotypic Synonyms

Althaea burchellii DC. in Prodr. 1: 438 (1824)

Malache burchellii (DC.) Kuntze in Revis. Gen. Pl. 1: 70 (1891)

Heterotypic Synonyms

Lebretonia acuminata A.Rich. in Tent. Fl. Abyss. 1: 54 (1848)

Pavonia crenata Hochst. ex A.Rich. in Tent. Fl. Abyss. 1: 53 (1848)

Pavonia kraussiana Hochst. in Flora 27: 293 (1844)

Perennial herb. Leaves usually weakly 3-lobed, ovate, crenate, base cordate. Flowers solitary in leaf axils, bright yellow to orange. Mericarps 5, woody, pubescent, reticulate, stellate. Seeds brown, obovate, and stellate. Rare in the study area, it grows on scrubby cliffs and rocky slopes at 1301 m above sea level.

(3): P. procumbens (Wight & Arn.) Walp. in Repert. Bot. Syst. 1: 301 (1842)

Homotypic Synonym

Lebretonia procumbens Wight & Arn. in Prodr. Fl. Ind. Orient. 1: 47 (1834)

Heterotypic Synonyms

Pavonia ctenophora Ulbr. in Bot. Jahrb. Syst. 57: 122 (1920)

Pavonia ukambanica Ulbr. in Bot. Jahrb. Syst. 57: 132 (1920)

Perennial herb. Leaves broadly ovate, cordate at the base, acute at the apex, with coarsely dentate margins. Flowers are solitary in leaf axils, yellow to orange, with red bases. Mericarps 5, puberulous, dorsal keel with a single or double row of spines, lateral ridges with long spines in the upper part. Seeds hairy stellate. It grows on field agricultural, shady places at altitudes between 701 and 981 m above sea level.

7.: Senra Cav. in Diss. 2: 83 (1786); TYPE: Senra incana Cav.
(1): S. incana Cav. in Diss. 2: 83 (1786)

Homotypic Synonym

Serraea incana (Cav.) Spreng. in Syst. Veg., ed. 16. 3: 78 (1826)

Heterotypic Synonyms

Senra arabica Webb in Fragm. Fl. Aethiop.-Aegypt.: 48 (1854)

Senra incana subsp. migiurtinorum Chiov. in Fl. Somala 1: 97 (1929)

Senra incana var. scassellatii (Mattei) Senni in Bibl. Agr. Col. 13: 58 (1935)

Senra nubica Webb in Fragm. Fl. Aethiop.-Aegypt.: 49 (1854)

Senra nubica var. microphylla Mattei in Boll. Reale Orto Bot. Palermo, n.s., 2: 67 (1917)

Senra nubica var. scassellatii Mattei in Boll. Reale Orto Bot. Palermo, n.s., 2: 67 (1917)

Serraea nubica (Webb) Mattei in Boll. Reale Orto Bot. Palermo, n.s., 2: 66 (1917)

Subshrubs. Leaves palmately, lobed, palmatifid, dentate, base cordate. Flowers are solitary, axillary, and yellow with a maroon base. The capsule is ovoid and entirely enclosed by the bracts, 5-valved. Seeds brown, and velutinous. Grow on edge wadis, fields, stony ground, and sandy soils on altitudes between 299 and 704 m above sea level (Figure 3L).

8.: Sida L. in Sp. Pl.: 683 (1753); LECTOTYPE: Sida alnifolia L., designated by Britton & Brown (1913).

Two species are widely distributed in the study area. The next dichotomous key distinguishes between them (Figure 3M,N):

1a. number of stigmas 5; fruit schizocarp indehiscent to 5 mericarps ……..……. 1. S. alba
1b. Number of stigmas 7–9; fruit schizocarp indehiscent to 7–9 mericarps ..…. 2. S. ovata

(1): S. alba L. in Sp. Pl., ed. 2.: 960 (1763)

Homotypic Synonym

Malvinda alba (L.) Medik. in Malvenfam.: 24 (1787)

Heterotypic Synonym

Sida spinosa var. sennaarensis Vis. in Pl. Aegypti: 27 (1836)

Perennial herb. Leaves ovate or elliptic, base rounded, acute to rounded at the apex, with dentate margins. Flowers solitary or in few-flowered axillary racemes, white. Mericarps 5, puberulous awns. Seeds smooth, brown to black, sub-obovate. It is a typical weed on the escarpment, clay plains, alluvial soils, derelict fields, tracksides, and stony agricultural land on altitudes between 684 and 783 m above sea level.

(2): S. ovata Forssk. in Fl. Aegypt.-Arab.: 124 (1775)

Heterotypic Synonyms

Sida abyssinica Hochst. ex D.Dietr. in Syn. Plant. 4: 859 (1846)

Sida grewioides Guill. & Perr. in Fl. Seneg. Tent.: 71 (1831)

Sida subrotunda Hochst. ex Lanza & Mattei in Boll. Reale Orto Bot. Palermo 8: 84 (1909)

Perennial herb. Leaves ovate, base rounded, subacute at the apex, with serrate-crenate margins. Flowers axillary, solitary or paired, yellow or orange. Mericarps 7–9, unawned. Seeds smooth, brown to black, obovate. It is a typical plant of the escarpment, silt plain, field borders, open stony slopes, and roadsides on altitudes between 691 and 841 m above sea level.

3.4.4. Subfamily: Sterculioideae Burnett in Outlines of Botany 821: 1119 (1835)

Trees with lobed leaves. Inflorescences are axillary, paniculate, epicalyx absent. Flowers usually gamosepalous, apetalous, and unisexual; androgynophore present (reduced in female flowers); stamens c. 10, filaments short or anthers (sub-)sessile; thecae distinct, often forming a whorl or head; staminodes absent; carpels 3–5, free. Fruits dehiscent follicles.

One genus, with one species, was recorded in the study area.

1.: Sterculia L. in Sp. Pl.: 1007 (1753); LECTOTYPE: Sterculia foetida L., designated by M. L. Green, Prop. Brit. Bot. 190 (1929)
(1): S. africana (Lour.) Fiori in Agric. Colon. 5 (Suppl.): 37 (1911 publ. 1912)

Homotypic Synonyms

Clompanus africana (Lour.) Kuntze in Revis. Gen. Pl. 1: 77 (1891)

Triphaca africana Lour. in Fl. Cochinch.: 577 (1790)

Heterotypic Synonyms

Clompanus arabica (T.Anderson) Kuntze in Revis. Gen. Pl. 1: 78 (1891)

Sterculia abyssinica R.Br. in Pterocymbium: 227 (1844)

Sterculia arabica T.Anderson in J. Proc. Linn. Soc., Bot. 5 (Suppl. 1): 9 (1860)

Tree. Leaves cordate, orbicular, or 3–5 lobed with acuminate apex. Flowers in small axillary panicles with the calyx reddish inside. Follicles 3–5, oblong-ovoid, thick-walled. Seeds dull black. Grows on exposed scrubby hillsides and rocky slopes 665–888 m above sea level (Figure 3O).

4. Discussion

The richness and phytogeographical distribution of the Malvaceae s.l. family in Yemen remains largely unexplored. The study area covers about 1881 km² and showed a marked richness in genera and species of the mallow family. This diversity represents approximately 48% and 27.68% of the total documented genera and species in the flora of Yemen [7,8]. The substantial diversity of genera and species within the mallow family can be attributed to the mosaic environment in the study area, which creates a variety of habitats characterized by distinct topographic variations, soil compositions, and water resources alongside influences from human and animal activities [23].

Malvoideae is the predominant subfamily, with eight genera and 17 species, while the Grewioideae subfamily includes two genera and 11 species (Table 1). This study documented a comparison of genera and species alongside previous investigations undertaken in several regions of Yemen (Table 2) [24,25,26].

The most species-rich genera are Grewia (7 species), Hibiscus (4 species), Abutilon (4 species), and Pavonia (3 species) (Table 1). The findings corresponded with research on the vegetation of southern Yemen [24,25,26]. The prominence of these genera may stem from their remarkable seed dispersal capability and extensive ecological adaptability.

The study indicated that the species’ life span was categorized as perennials, comprising 24 species (80%), whereas annuals accounted for 6 species (20%) of the total recorded species. The prevalence of perennial species can be explained by the insufficient rainfall, which fails to support a significant number of annuals. Perennials are adapted to the extreme habitats of the region, resulting in a distinctive physiognomy of the plant cover [23,28,29].

The Mallow family of the Toor Al-Baha district exhibits a great diversity of life forms. Plant life forms were categorized as Chamaephytes (50%), Phanerophytes (30%), and Therophytes (20%) (Table 1). Chamaephytes dominated the study area. These results agreed with prior research conducted in several regions of Yemen [26,30]. Moreover, similar results were observed in the adjacent countries, specifically Saudi Arabia [23,31,32]. The prevalence of Chamaephytes can be ascribed to the arid climate, topographical diversity, and biotic factors. Chamaephytes can endure waterlogging, elevated salinity, and a spectrum of temperature fluctuations [32,33,34].

A chorological analysis of the 30 mallow species surveyed in the study area revealed that 25 species (83.34% of the recorded taxa) have Sudano-Zambezian affinities. Most Sudano-Zambezian species were bi-regional (10 species = 33.33% of the recorded taxa) of two main chorotypes: the Saharo-Sindian/Sudano-Zambezian elements together have the highest share of species (8 species), representing 26.68% of the total mallow species surveyed, followed by the Sino-Japanese/Sudano-Zambezian elements, represented by 2 species (6.67%), followed by the pluriregional elements (10 species = 33.33% of the recorded taxa) of different affinities (Figure 2, Table 1). Meanwhile, five species had monoregional distribution (pure Sudano-Zambezian), representing 16.68% of the total taxa. Similar results were obtained in different studies of the flora of Yemen and neighboring countries [8,23,30].

The prevalence of Sudano-Zambezian features in the research area is anticipated, given that the southern and southwestern Arabian Peninsula is among the most affluent regions of the Sudanian (Sudano-Zambezian) lands [6,35]. The South Arabian subregion extends the Sudano-Zambezian region, encompassing portions of southern Saudi Arabia and Yemen next to the Red Sea and the Gulf of Aden [36].

5. Conclusions

This study comprehensively revised the family Malvaceae sensu lato in the flora of Toor Al-Baha District, Lahij Governorate, southern Yemen. A total of 30 species, representing 12 genera across four subfamilies (Dombeyoideae, Grewioideae, Malvoideae, and Sterculioideae), were documented. Updated plant names and newly developed identification keys were introduced to enhance the accuracy of species identification within the mallow family in Yemen. The morphological characteristics of both vegetative and reproductive structures showed considerable taxonomic value, successfully differentiating between species at various levels. These findings contribute to a deeper understanding of the Malvaceae family in the region and offer valuable resources for upcoming floristic and taxonomic investigations.

Author Contributions

Conceptualization, O.S.S.A.-H. and M.O.B.; methodology M.O.B.; software A.K.O.; validation, O.S.S.A.-H., A.K.O. and A.M.A.; formal analysis, A.M.A.; investigation, M.O.B.; resources, A.M.A.; data curation, O.S.S.A.-H.; writing—original draft preparation O.S.S.A.-H., A.K.O. and M.O.B.; writing—review and editing, A.M.A. and R.N.A.; visualization, O.S.S.A.-H.; supervision, A.K.O.; project administration O.S.S.A.-H.; funding acquisition, A.M.A. and R.N.A. All authors have read and agreed to the published version of the manuscript.

Funding

The authors extend their appreciation to the Deanship of Research and Graduate Studies at King Khalid University for funding this work through a Large Group Project under grant number (RGP. 2/466/45).

Institutional Review Board Statement

Not applicable.

Data Availability Statement

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.

Acknowledgments

The authors gratefully acknowledge the financial support provided by the Deanship of Research and Graduate Studies at King Khalid University, and we deeply appreciate their dedication to advancing scientific research.

Conflicts of Interest

The authors declare no conflicts of interest.

Abbreviations

The following abbreviations are used in this manuscript:

Spp.	Species (plural)
subsp.	Subspecies
var.	Variety

References

POWO Plants of the World Online. Facilitated by the Royal Botanic Gardens, Kew. Available online: http://powo.science.kew.org/ (accessed on 2 January 2025).
Utteridge, T.; Bramley, G. The Kew Tropical Plant Families Identification Handbook, 2nd ed.; Kew Publishing Royal Botanic Garden: Kew, UK, 2016; ISBN 1842463810. [Google Scholar]
EPA. Assessing Progress Towards the 2010 Target—The 4th National CBD Report; EPA: New York, NY, USA, 2009.
Akhani, H. Diversity, Biogeography, and Photosynthetic Pathways of Argusia and Heliotropium (Boraginaceae) in Southwest Asia with an Analysis of Phytogeographical Units. Bot. J. Linn. Soc. 2007, 155, 401–425. [Google Scholar] [CrossRef]
Gabali, S.A. Plant Life in Yemen. A General Survey and Preliminary Checklist of the Flowering Plant Species; Aden University Press: Aden, Yemen, 1995. [Google Scholar]
Zohary, M. Geobotanical Foundations of the Middle East. Vol. 1–2; Gustav Fischer Verlag Press, Stuttgart, Swets & Zeitlinger: Amsterdam, The Netherlands, 1973. [Google Scholar]
Al-Khulaidi, A.A. Flora of Yemen. In Sustainable Natural Resource Management Project (SNRMP) II, Sana’a, Yemen; Yemen Biodiversity: Socotra, Yemen, 2013; p. 266. [Google Scholar]
Al-Hawshabi, O.; Al-Meisari, M.; El-Naggar, S. Floristic Composition, Life-Forms and Biological Spectrum of Toor Al-Baha District, Lahej Governorate, Yemen. Curr. Life Sci. 2017, 3, 72–91. [Google Scholar]
Alharbi, S.A.; Al-Hawshabi, O.S.S.S.; Badry, M.O. Flora and Phytochorolgy of Lahij Governorate of Yemen: 2-Taxonomic Revision of Corchorus L. (Grewioideae-Malvaceae Sensu Lato) in Toor Al-Baha District. Egypt. J. Bot. 2024, 64, 375–385. [Google Scholar] [CrossRef]
Wood, J.R.I. A Handbook of the Yemen Flora; Royal Botanic Gardens: Kew, UK, 1997; Volume 40, p. 434. [Google Scholar]
Kilian, N.; Hein, P.; Hubaishan, M.A. New and Noteworthy Records for the Flora of Yemen, Chiefly of Hadhramout and Al-Mahra. Willdenowia 2002, 32, 239–269. [Google Scholar] [CrossRef]
The Angiosperm Phylogeny Group. An Update of the Angiosperm Phylogeny Group Classification for the Orders and Families of Flowering Plants: APG III. Bot. J. Linn. Soc. 2009, 161, 105–121. [Google Scholar]
The Angiosperm Phylogeny Group. An Update of the Angiosperm Phylogeny Group Classification for the Orders and Families of Flowering Plants. Bot. J. Linn. Soc. 2016, 181, 1–20. [Google Scholar] [CrossRef]
Boulos, L. Flora of Egypt, Volume 2: Geraniaceae—Boraginaceae; Al Hadara Publishing: Cairo, Egypt, 2000; p. 352. [Google Scholar]
Chaudhary, S.A. Flora of the Kingdom of Saudi Arabia, Illustrated, Volume 1; National Herbarium, National Agriculture and Water Research Center, Ministry of Agriculture & Water: Riyadh, Saudi Arabia, 1999. [Google Scholar]
Ghazanfar, S.A. Flora of the Sultanate of Oman. Vol. 1: Piperaceae–Primulaceae (Text + Photo CD-ROM); National Botanic Garden of Belgium: Meise, Belgium, 2003; Volume 25, p. 220. [Google Scholar]
Hedberg, I.; Hedberg, O.; Edwards, S. Flora of Ethiopia and Eritrea. Vol. 2. Part 2, Canellaceae to Euphorbiaceae; National Herbarium, Addis Ababa University: Addis Ababa, Ethiopia, 1995. [Google Scholar]
Thulin, M. Flora of Somalia. Vol. 2; Royal Botanic Gardens: Kew, UK, 1999. [Google Scholar]
Hassib, M. Distribution of Plant Communities in Egypt. Bull. Fac. Sci. Univ. Fouad 1 1951, 29, 59–261. [Google Scholar]
Raunkiaer, C. The Life Forms of Plants and Statistical Plant Geography; Clarendon Press: Oxford, UK, 1934. [Google Scholar]
White, F.; Leonard, J.; Léonard, J. Phytogeographical Links between Africa and Southwest Asia. Flora Veg. Mundi 1991, IX, 229–246. [Google Scholar]
Bayer, C.; Kubitzki, K. Malvaceae. In Flowering Plants-Dicotyledons: Malvales, Capparales and Non-betalain Caryophyllales; Kubitzki, K., Bayer, C., Eds.; Springer Berlin Heidelberg: Berlin/Heidelberg, Germany, 2003; pp. 225–311. [Google Scholar]
Abbas, A.M.; Al-Kahtani, M.A.; Alfaifi, M.Y.; Elbehairi, S.E.I.; Badry, M.O. Floristic Diversity and Phytogeography of JABAL Fayfa: A Subtropical Dry Zone, Southwest Saudi Arabia. Diversity 2020, 12, 345. [Google Scholar] [CrossRef]
Boulos, L. A Contribution to the Flora of South Yemen (PDRY). Candollea 1988, 43, 549–585. [Google Scholar]
Gabali, S.A.; Al-Gifri, A. Flora of South Yemen—Angiospermae A Provisional Checklist. Feddes Repert. 1990, 101, 373–383. [Google Scholar]
Saif, A.A.-M.A.; Al-Mosanif Ghaleb, I.M.; Al-Hawshabi, O.S.S. Flora of Erf Jabal, Al-Maqaterah District, Lahej Governorate, Yemen. Electron. J. Univ. Aden Basic Appl. Sci. 2024, 5, 186–200. [Google Scholar]
Atif, M.A.A.S.; Al-Super, A.M.M.; Al-Hawshabi, O.S.S. Floristic Composition, Life-Forms and Chorotypes of Plants for Extended Area from Aqan to Al-Erais, Lahej Governorate, Yemen. J. Appl. Nat. Sci. 2024, 8, 40–63. [Google Scholar]
El-Amier, Y.A.A. Vegetation Structure and Soil Characteristics of Five Common Geophytes in Desert of Egypt. Egypt. J. Basic Appl. Sci. 2016, 3, 172–186. [Google Scholar] [CrossRef]
Shaltout, K.H.; Sheded, M.G.; Salem, A.I. Vegetation Spatial Heterogeneity in a Hyper Arid Biosphere Reserve Area in North Africa. Acta Bot. Croat. 2010, 69, 31–46. [Google Scholar]
Al-Hawshabi, O.S.S. Floristic Composition, Life-forms and Chorotypes of Al-Asabah Region, Ash Shamayatayn District, Taiz Governorate, Yemen. Feddes Repert. 2017, 128, 42–54. [Google Scholar] [CrossRef]
Al-Robai, S.A.; Mohamed, H.A.; Howladar, S.M.; Ahmed, A.A. Vegetation Structure and Species Diversity of Wadi Turbah Zahran, Albaha Area, Southwestern Saudi Arabia. Ann. Agric. Sci. 2017, 62, 61–69. [Google Scholar] [CrossRef]
Shalabi, L.F.; Masrahi, Y.S. Floristic Composition, Life Forms and Phytogeography of Al-Hashr Mountain, Jazan Region, SW Saudi Arabia. Egypt. J. Exp. Biol. 2019, 15, 73–85. [Google Scholar]
Alshammari, A.S. Soil Classification, Water Quality and Chemical Pollution of Some Crops and Soils at Farms in Wadi Al-Aderaa–Hail. Ph.D. Thesis, Faculty of Meteorology, Environment and Arid Land Agriculture—King Abdu Aziz University, Jeddah, Saudi Arabia, 2013. [Google Scholar]
Hegazy, A.K.; Kabiel, H.F.; Al-Rowaily, S.L.; Lovett-Doust, L.; Al Borki, A.E.N.S. Plant Communities and Reproductive Phenology in Mountainous Regions of Northern Libya. J. For. Res. 2017, 28, 741–761. [Google Scholar] [CrossRef]
Takhtajan, A. Floristic Regions of the World; Crovello, T.J., Translator; University of California Press: Los Angeles, CA, USA, 1986. [Google Scholar]
Wickens, G.E. Some of the Phytogeographical Problems Associated with Egypt. Publ. Cairo Univ. Herb. 1977, 7–8, 223–230. [Google Scholar]

Figure 1. Map of Yemen administrative divisions showing the study area of Toor Al-Baha district at Lahij Governorate. Adapted from Kilian et al. [11].

Figure 2. Chorological analysis of wild mallows in Toor Al-Baha district, Lahij Governorate, Yemen. For abbreviations, see Table 1.

Figure 3. Wild mallow species in the study area. (A) Melhania muricata; (B) Cienfuegosia welshii; (C) Gossypium arboreum; (D) Hibiscus deflersii; (E) H. palmatus; (F) H. trionum; (G) H. vitifolius; (H) Pavonia arabica; (I) Pavonia burchellii; (J) Pavonia procumbens; (K) Malvastrum coromandelianum; (L) Senra incana; (M) Sida alba; (N) Sida ovata; (O) Sterculia africana.

Figure 4. Corchorus L. species in the study area. 1. Vegetative part of the plant with flowering and fruiting buds. 2. Close-up view of an open flower and/or fruit. (A) C. depressus; (B) C. olitorius; (C) C. tridens; (D) C. trilocularis [9].

Figure 5. Grewia L. species in the study area. 1. Vegetative part of the plant with flowering buds. 2. Fruits. (A) G. arborea; (B) G. erythraea; (C) G. schweinfurthii; (D) G. tembensis var. ellenbeckii; (E) G. tenax; (F) G. tristis; (G) G. velutina.

Figure 6. Abutilon Mill. species in the study area. 1. Vegetative part of the plant with flowering buds. 2. Fruits. (A) A. bidentatum; (B) A. fruticosum; (C) A. hirtum; (D) A. pannosum var. figarianum.

Table 1. List of species Malvaceae s.l. recorded in Toor Al-Baha District, Lahij Governorate, Yemen, along with their subfamilies, growth forms, life span, life form, chorotypes, location, and ordinates.

No.	Taxa	Growth Forms	Life Span	Life Form	Chorotype	Location	Latitude (N)	Longitude (E)
Subfamily: Dombeyoideae (1)
1	Melhania muricata Balf. f.	Herb	Perennial	Ch.	SS + SZ	Above wadi Almalhein	13°03′533″	44°21′231″
Subfamily: Grewioideae (11)
2	Corchorus depressus (L.) Peterm.	Herb	Perennial	Ch.	IT + SS + SZ	Almaamia village	13°12′328″	44°19′463″
3	Corchorus olitorius L.	Herb	Annual	Th.	PAL	Alawja village	13°12′694″	44°18′193″
4	Corchorus tridens L.	Herb	Annual	Th.	TR	Zarit	13°11′911″	44°17′319″
5	Corchorus trilocularis L.	Herb	Annual	Th.	CA + IT + SS + SZ	Shaib Eibed	13°13′355″	44°20′266″
6	Grewia arborea (Forssk.) Lam.	Shrub	Perennial	Ph.	SJ + SZ	Jabal Khulaqah	13°12′073″	44°27′533″
7	Grewia erythraea Schweinf.	Shrub	Perennial	Ph.	IT + SS + SZ	Jabal Althumah	13°02′736″	44°16′078″
8	Grewia schweinfurthii Burret	Shrub	Perennial	Ph.	SZ	Zarit	13°11′911″	44°17′319″
9	Grewia tembensis var. ellenbeckii Burret	Shrub	Perennial	Ph.	SZ	Jabal Althumah	13°02′736″	44°16′078″
10	Grewia tenax (Forssk.) Fiori	Shrub	Perennial	Ph.	ME + IT + SS + SZ	Above Wadi Almalhein	13°03′533″	44°21′231″
11	Grewia tristis K. Schum	Shrub	Perennial	Ph.	SZ	Shaib Eibed	13°12′977″	44°20′177″
12	Grewia velutina (Forssk.) Lam.	Shrub	Perennial	Ph.	SS + SZ	Shaib Eibed	13°13′355″	44°20′266″
Subfamily: Malvoideae (17)
13	Abutilon bidentatum (Hochst) A.Rich.	Shrub	Perennial	Ch.	SJ + SS + SZ	Alawja village	13°12′569″	44°18′101″
14	Abutilon fruticosum Guill. & Perr.	Shrub	Perennial	Ch.	PAN	Albaudha village	13°11′989″	44°17′735″
15	Abutilon hirtum (Lam.) Sweet var. hirtum	Shrub	Perennial	Ch.	IT + SJ + SS + SZ	Albaudha village	13°11′989″	44°17′735″
16	Abutilon pannosum var. figarianum (Webb) Verdc.	Shrub	Perennial	Ch.	SS + SZ	Shaib Al-Awsat	13°12′328″	44°19′463″
17	Cienfuegosia welshii (T.Anderson) Garcke	Subshrub	Perennial	Ch.	SS + SZ	Above wadi Almalhein	13°03′533″	44°21′231″
18	Gossypium arboreum L.	Shrub	Perennial	Ph.	SZ	Habiel Alsabat	13°10′616″	44°18′243″
19	Hibiscus deflersii Schweinf. ex Cufod.	Subshrub	Perennial	Ch.	SS + SZ	Shaib Eibed	13°13′024″	44°20′367″
20	Hibiscus palmatus Forssk.	Herb	Annual	Th.	IT + SS + SZ	Alawja village	13°12′569″	44°18′101″
21	Hibiscus trionum L.	Herb	Annual	Th.	ES + IT + ME + SS + SZ	Alawja village	13°12′694″	44°18′193″
22	Hibiscus vitifolius L.	Subshrub	Perennial	Ch.	PAN	Zarit	13°12′044″	44°17′436″
23	Malvastrum coromandelianum (L.) Garcke	Herb	Annual	Th.	NEO	Zarit	13°11′841″	44°17′652″
24	Pavonia arabica Hochst. & Steud. ex Boiss.	Herb	Perennial	Ch.	SS + SZ	Zarit	13°11′878″	44°17′408″
25	Pavonia burchellii (DC.) R.A.Dyer	Subshrub	Perennial	Ch.	CA + SS + SZ	Jabal Khulaqah	13°12′073″	44°27′533″
26	Pavonia procumbens (Wight & Arn.) Walp.	Subshrub	Perennial	Ch.	SJ + SZ	Alawja village	13°12′569″	44°18′101″
27	Senra incana Cav.	Subshrub	Perennial	Ch.	SS + SZ	Wadi Almalhein	13°03′533″	44°21′231″
28	Sida alba L.	Subshrub	Perennial	Ch.	SS + SZ	Alawja village	13°12′569″	44°18′101″
29	Sida ovata Forssk.	Herb	Perennial	Ch.	IT + SS + SZ	Alawja village	13°12′569″	44°18′101″
Subfamily: Sterculioideae (1)
30	Sterculia africana (Lour.) Fiori	Tree	Perennial	Ph.	SZ	Haijet Maafa	13°12′096″	44°17′717″

Life form abbreviations: Ch.: Chamaephyte; Ph.: Phanerophyte; Th.: Therophyte. Chorotype abbreviations: CA: Cape Verde; ES: Euro-Siberian; ME: Mediterranean; NEO: Neotropical; PAL: Palaeotropical; PAN: Pantropical; IT: Irano-Turanian; SJ: Sino-Japanese; SS: Saharo-Sindian; SZ: Sudano-Zambezian. TR: Tropical.

Table 2. The number of genera and species of the family Malvaceae s.l. was reported by different authors who were concerned with the flora of Yemen.

	Study
Category	Boulos [24]	Gabali and Al-Gifri [25]	Al-Khulaidi [7]	Abbas et al. [23]	Saif et al. [26]	Atif et al. [27]	Current Study
No. genera	11	13	25	8	8	7	12
No. species	18	18	112	13	18	10	30

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Al-Hawshabi, O.S.S.; Osman, A.K.; Abbas, A.M.; AlQthanin, R.N.; Badry, M.O. Flora and Phytochorology of Lahij Governorate of Yemen: 3-Systematic Revision of Malvaceae s.l. in Toor Al-Baha District. Diversity 2025, 17, 242. https://doi.org/10.3390/d17040242

AMA Style

Al-Hawshabi OSS, Osman AK, Abbas AM, AlQthanin RN, Badry MO. Flora and Phytochorology of Lahij Governorate of Yemen: 3-Systematic Revision of Malvaceae s.l. in Toor Al-Baha District. Diversity. 2025; 17(4):242. https://doi.org/10.3390/d17040242

Chicago/Turabian Style

Al-Hawshabi, Othman S. S., Ahmed K. Osman, Ahmed M. Abbas, Rahmah N. AlQthanin, and Mohamed O. Badry. 2025. "Flora and Phytochorology of Lahij Governorate of Yemen: 3-Systematic Revision of Malvaceae s.l. in Toor Al-Baha District" Diversity 17, no. 4: 242. https://doi.org/10.3390/d17040242

APA Style

Al-Hawshabi, O. S. S., Osman, A. K., Abbas, A. M., AlQthanin, R. N., & Badry, M. O. (2025). Flora and Phytochorology of Lahij Governorate of Yemen: 3-Systematic Revision of Malvaceae s.l. in Toor Al-Baha District. Diversity, 17(4), 242. https://doi.org/10.3390/d17040242

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Flora and Phytochorology of Lahij Governorate of Yemen: 3-Systematic Revision of Malvaceae s.l. in Toor Al-Baha District

Abstract

1. Introduction

2. Materials and Methods

3. Results

3.1. Floristic Composition

3.2. Life Form Spectra

3.3. Chorological Affinities

3.4. Artificial Dichotomous Key for Identifying Subfamilies of the Malvaceae s.l. Family Recorded in Toor Al-Baha District, Lahij Governorate

3.4.1. Subfamily: Dombeyoideae Beilschm. in Flora 16 (2): 86, 106 (1833)

3.4.2. Subfamily: Grewioideae Dippel in Handbuch der Laubholzkunde 3: 56–57 (1893)

3.4.3. Subfamily: Malvoideae Burnett in Outlines of Botany 816: 1094-1118 (1835)

3.4.4. Subfamily: Sterculioideae Burnett in Outlines of Botany 821: 1119 (1835)

4. Discussion

5. Conclusions

Author Contributions

Funding

Institutional Review Board Statement

Data Availability Statement

Acknowledgments

Conflicts of Interest

Abbreviations

References

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