**1. Introduction**

Founded in 2015, the Global Genome Initiative for Gardens (GGI-Gardens, [1]) is an international partnership of botanic gardens and arboreta that aims to preserve and understand Earth's genomic diversity of plants. GGI-Gardens supports the collection of both herbarium and genomic voucher material from the living collections in these partner gardens following best practices for herbarium and genomics research [2]. Collections made through this program are stored in Global Genome Biodiversity Network (GGBN)- partnered DNA banks [3], meaning that they can be utilized for applications ranging from whole genome sequencing [4] to DNA barcoding [5], as well as other genomic research.

Since their conception in 2003 [6], DNA barcode sequences have been used as powerful tools that enable the large-scale and rapid taxonomic identification of species for myriad purposes, including conservation [7], forensics [8], and the quantification of species diversity [9], among others. Emerging techniques, such as metabarcoding [10,11], leverage high-throughput sequencing technology and are capable of sequencing a mixed or pooled sample of species and identify them from their barcode sequence.

An important limiting factor for these and other studies that utilize DNA barcode sequences, however, is the representation of species diversity in reference databases [12]. DNA barcode reference databases are growing in both their taxonomic and geographic scope thanks to a number of large initiatives, which often focus on a particular branch of the tree of life or geographic area. For example, since 2005, the African Centre for DNA Barcoding has been contributing DNA barcode reference sequences from Africa to facilitate improved DNA barcoding applications from this continent [13]. The basic concept of DNA

**Citation:** Gostel, M.R.; Carlsen, M.M.; Devine, A.; Barker, K.B.; Coddington, J.A.; Steier, J. Data Release: DNA Barcodes of Plant Species Collected for the Global Genome Initiative for Gardens (GGI-Gardens) II. *Diversity* **2022**, *14*, 234. https://doi.org/ 10.3390/d14040234

Academic Editor: Mario A. Pagnotta

Received: 11 February 2022 Accepted: 18 March 2022 Published: 23 March 2022

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barcoding has also expanded during recent years, thanks to high-throughput sequencing (HTS) technology and methods to "extend" the traditional barcode concept include the use of so-called "genome-skim" data [14] or whole organelle genome sequences as "super-" [15] or "ultra-barcodes" [16]. Clade-based approaches are contributing large-scale DNA barcode reference sequences for entire groups of organisms that are often regionally focused [17] or even hyper locally focused (e.g., sequencing living collections from botanic gardens, [18]), and in this paper we provide a large contribution from collections made by the GGI-Gardens program.

Facilitated by the Global Genome Initiative based at Smithsonian Institution (https: //naturalhistory.si.edu/research/global-genome-initiative, accessed on 30 January 2022), new families and genera collected by GGI-Gardens partners to date have been extracted and sequenced using four plant DNA barcode loci (*rbcL*, *matK*, ITS2, and *psbA-trnH*). Past collections made through the GGI-Gardens program have been published as part of large DNA barcode "data releases", the first of which included the publication of nearly 2000 barcode sequences [5]. This manuscript represents the second data release for samples collected through the GGI-Gardens program and will serve as a significant contribution to available plant DNA barcode sequences in public repositories. These barcode sequences will facilitate future plant biodiversity research by improving the ability of researchers to use DNA barcode sequences to accurately identify species from DNA barcode reference databases through general plant inventories, ecological studies, and metabarcoding studies.
