Draba incerta
| Draba incerta | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Draba incerta |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Draba incerta | ||||||||||||
| Payson |
Draba incerta (English common name : Yellowstone Draba ) is a species of rock flower within the cruciferous family(Brassicaceae). Two varieties are known: Draba incerta var. Incerta and Draba incerta var. Peasei . The latter is probably extinct .
description
Draba incerta var. Incerta
Draba incerta var. Incerta is a perennial herbaceous plant that forms fairly loose mats. It reaches heights of growth of 3 to 12 centimeters and grows up to 20 centimeters in width. The relatively few stems covered with forked or branched trichomes are leafless or sometimes have a simple bract. The tufted, erect, full-margined, linearly inverted lanceolate basal leaves are 7 to 13 mm long and hairy on the underside with short-stemmed, branched or comb-shaped trichomes.
The flowering period extends from June to July. The inflorescences contain 3 to 15 flowers. The hermaphrodite flowers are fourfold. The color of the petals is yellow, which turns into a whitish shade. The hairy or bald fruit stalks are up to 18 mm long. The flattened 6 to 10 mm long and 4 mm wide pods are oval-lanceolate to elliptical and hairy with simple or forked trichomes. The styles are 0.4 to 1 mm and the seeds are 1.2 to 1.5 mm long.
Draba incerta var. Peasei
The variety Draba incerta var. Peasei (Fernald) Rollins reaches heights of growth of about 4 centimeters. The oval pods are covered with multi-branched trichomes . The flowering time is in June. The holotype was collected in 1928 by Arthur Stanley Pease , a Harvard professor of botany , on a scree slope of Mont Saint-Alban near Cap-des-Rosiers on the Gaspésie peninsula . Merritt Lyndon Fernald described the herbarium material in 1934 under the name Draba peasei . In 1991 the taxon was classified by Reed Clark Rollins as a variety of Draba incerta .
Occurrence and endangerment
Draba incerta var. Incerta occurs in Yellowstone National Park in Wyoming , in Alaska , Colorado , Montana , Washington , Oregon , Nevada , Idaho , Utah and in the Canadian provinces of Alberta , British Columbia , Quebec and Yukon . The distribution area of Draba incerta var. Peasei was limited to the Gaspésie peninsula .
The habitats are limestone cliffs and scree slopes, rubble slopes, peaks and slopes of alpine regions, crevices, weathered slate heaps, gravel beds, open slopes and the alpine tundra .
status
Draba incerta var. Incerta is common in most of the range. It is rare in Colorado, Idaho and Utah. Draba incerta var. Peasei, however, was last detected in July 1936 by the Canadian botanist Frère Louis Rolland-Germain . In the 1970s and 1990s, the botanist Pierre Morisset from the University of Laval undertook research expeditions for this plant species, but they were unsuccessful.
literature
- Reed Clark Rollins: The Cruciferae of continental North America. Systematics of the mustard family from the Arctic to Panama. Stanford University Press, Stanford CA 1993, ISBN 0-8047-2064-9 .
