Al Schneider's Rocky Mountains Plant Descriptions

Mountain Tansymustard
Descurainia incana
Mustard family (Brassicaceae)

This is a variable species, broken by some botanists into varieties which other botanists consider species. The flowers of this Mustard are quite small but they are in relatively large, clusters. The plant is slender, tall, and has bright green, finely cut leaves. Descurainia incana is found in and higher altitudes in Colorado, New Mexico, and Utah. Characteristics that help separate various Descurainia (and various Mustards in general) are: how flattened are the seed pods; how long, short, or round are the pods; and how do the pods extend from the flower, i.e., horizontally, vertically, curved, etc. D. incana was first described and named (probably Descurainia richardsonii) by Bernhardi and then was renamed Descurainia incana by Dorn. "Incan" means "hoary" or "quite gray."


© Mary Ellen (Mel) Harte, Bugwood.org

Description

to . Stems from 1-4' tall, simple or more commonly profusely branching from upper leaf axils, minutely hairy and minutely to almost lower on stem, or above. and , 2/3 to 3" long, , the upper reduced in size. from 1/8 to 1/3" long, spreading to erect, or . spreading, yellow or green, or hairy. Petals to about 1/8" long, yellow. from 1/3 to over 1/2" long, very narrow, , curving upward or strictly upward, often .

Field Marks

Tall, airy mustard with finely cut leaves and clusters of tiny flowers that give rise to numerous seed pods that usually are vertical pressing against the stem.

© Al Schneider

cauline -- Leaves that are on the stem. Not basal.

linear -- Long and very narrow like a blade of grass.

pedicel -- The stem of a single flower.

pubescent -- downy; covered with short, soft, erect hairs.

An annual plant is a plant that completes its life cycle, from germination to the production of seed, within one year, and then dies.

Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom.

terminal -- Located at the end (the tip or the apex).

Glands are plant structures that secrete liquids, salts or other substances. Glands often appear as hairs with a drop of liquid at the end.

fruit -- any seed-bearing structure in flowering plants. It is formed from the ovary after flowering.

pinnate -- A compound leaf with two rows of leaflets.

biennial -- a plant which lives for two years, producing a basal rosette of leaves the first year and a full plant, flower, and seed the second year followed by the death of the entire plant at the end of the second year.

montane -- inhabiting mountainous country but below timberline.

appressed -- pressed close or flat against another surface as in hairs appressed against a stem.

basal leaves -- a leaf that grows lowest on the stem of a plant.

glabrous -- smooth, glossy, having no bristles or hair-like structures. Bald.