How to know the Texas Arabideae (Genera Draba, Abdra, and Tomostima)
Species of the Tribe Arabideae are among the first flowers to bloom (January--March or early April). Being small and inconspicuous, they are often overlooked (especially Draba reptans). Observations of Texas Arabideae are here. These species have been lumped and split, taxonomically; recently, all were in the genus Draba. The following characteristics vary, so documenting multiple characteristics will confirm the ID. Features to capture include:
- side view of mature fruits (pods)
- side view of flowering stem (pedicel) from top to bottom (with hairs in focus)
- view of leaves
Also, young plants may be challenging or impossible to identify.
- 1. The hairs on leaves and stems lie flat (appressed); mature fruit <5 mm long: Abdra brachycarpa (formerly Draba) [resource]
- 1. The hairs on leaves and stems are upright (perpendicular to surface); mature fruit 5-15 mm long
- 2. Pedicels (flowering stem) smooth (glabrous); leaves always entire (not notched): Tomostima (Draba) reptans [resource]
- 2. Pedicels pubescent; at least some leaves usually with 1+ pair of teeth
- 3. Leaves crowded near base; fruit elongate, blade-like; hairs along the stem branched: Tomostima (Draba) cuneifolia [resource]
- 3. Leaves extending up stem: fruit oval, football-shaped; many hairs along the stem unbranched: Tomostima (Draba) platycarpa [resource]
*There is also a yellow-flowered species in Jeff Davis county (Trans-Pecos): Draba standleyi
