*3.4. Morphology by SEM*

SEM photos for the flower's epidermis are illustrated (Figures 9 and 10), in which the photos show pubescent indumentum, consisting of stellate (star-shaped) base cells with uniseriate tapered ending. The trichomes are prominent and appear at high density. The SEM photos for the flowers are illustrated for the first time in the literature.

**Figure 9.** Flower epidermis trichomes of *A javanica* (magnification: 400×).

**Figure 10.** Flowers epidermis trichomes of *A javanica* (magnification: 800×).

The glandular trichomes indicating thero-tolerance by dissipating heat from the surface of the plant, which play a major role in enhancing the water use efficiency through adjusting the osmotic potential, which is a natural adaptation mechanism for desert plants in arid regions. Besides, the glandular trichomes are suspended to produce secondary metabolites, such as EOs, and acting as defense phytochemicals against biotic (e.g., herbivores) and abiotic (e.g., high temperature, low precipitation) stress factors [11,20].

The appearance of all the mentioned morphological features justifies the fact that *A. javanica* is a desert xerophytic plant that can survive high temperatures and high sun exposure rates with minimal water requirements. Furthermore, the existence of glandular trichomes on the epidermis of the flower supports the fact that *A. javanica* is an EO-bearing plant.
