Al Schneider's Rocky Mountains Plant Descriptions

Richardson's Bitterweed
Hymenoxys richardsonii
Aster family (Asteraceae)

Warm, dry, open areas can have a golden glow from numerous clusters of Colorado Rubber weed. Each plant has numerous stems and each stem produces a number of flowerheads. These plants probably are called "rubberweed" because the Amerindians of New Mexico made chewing gum from the bark and roots. The name, Hymenoxys, is from the Greek for "membrane" and "sharp," apparently alluding in some way to the structure of the . John Richardson was a surgeon and naturalist who served on two Arctic and Canadian expeditions in the 1800s.


© Mary Ellen (Mel) Harte, Bugwood.org

Description

Bushy, with dense bed of dead leaf bases. Leaves form a tuft around each stem. Few to numerous stems to 18" tall, below, branched above. and along stem, to 6" long, broken into three segments, or some , hairy to . Outer joined at their base, hairy. 9-14, yellow, to nearly an inch long. Central disc to 1/2" across. a hairy .

Field Marks

Finely cut leaves, bushy growth of numerous stems topped by many golden flowerheads.

© Al Schneider

An entire leaf has smooth edges. Not toothed or lobed.

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

achene -- a type of simple dry fruit produced by many species of flowering plants. For example, a rose hip holds a few achenes.

A herb is a plant whose stems die back to the ground in the winter.

ray flowers -- The outer petals of a sunflower or daisy are ray flowers.

caespitose -- Grass (or plants) growing in small dense clumps or tufts.

Bracts are modified leaves associated with a flower.

Involucre is the name given to the circle or spiral collection of bracts around a flower-cluster.

pappus -- Small scales, bristles or hairs at the top of the seed in Asteraceae. For example, dandelion parachutes. Plural: pappi.

basal -- at the base, situated or attached at the base.

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

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

genus -- A subdivision of a botanical Family in which all members have a significant number of similar characteristics.

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

A simple leaf blade is one that is not divided into separate leaflets.