Wednesday, February 22, 2012

Botany A to Z: Draba

By Karin Decker

is for Draba

Drabas belong to the Mustard family (Brassicaceae), and in fact, Draba is the largest genus in the family, both worldwide and in North America.  There are currently 121 recognized Draba species in the Flora of North America, with the greatest concentration of species in the western United States. Most species of Draba are found at high elevations or high latitudes, and endemism in local mountain ranges is frequent in the genus.
High elevation habitat beloved by Draba crassa and D. streptobrachia.

 Draba graminea in tough habitat - small but durable!
The original Greek name was applied to a type of cress. The common name of whitlow-grass apparently got attached to Draba verna because it was a plant believed to cure whitlows (look it up - eew!).

Are Drabas drab? Not when they are flowering - look at Draba borealis!

Oh, well, Draba fladnazensis is a little shy and retiring.

As a genus, Draba hasn't really settled on a single reproductive method – different species may reproduce via apomixis (various forms of asexual reproduction), autogamy (self-pollination), or outcrossing (exchanging pollen with other individuals). All of this can make taxonomic classification of the various species difficult to work out, since the plants don’t easily fit into the biological species concept, where the units of classification are interbreeding populations.
There are more than 2 dozen species of Draba reported from Colorado, and seven of them are endemic to the state. CNHP tracks 16 species:
Documented locations of rare Draba species in Colorado. Endemic species are colored and labeled, non-endemic are gray.

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