Al Schneider's Rocky Mountains Plant Descriptions

Heartleaf Arnica
Arnica cordifolia
Aster family (Asteraceae)

All western species of Arnica have paired leaves on the stems. Arnica latifolia is similar to Arnica cordifolia in many of its features but it has a number of differences: the of its lower stem leaves are shorter than the leaves (versus longer in A. cordifolia); its do not have the tuft of hairs at their tips that those of A. cordifolia usually do; and its leaves are not .

The word "Arnica" means "lamb's skin," and probably refers to the downy soft leaves. "Cordifolia" means "heart-leaf," but, although the heart-shape is often evident, Arnica cordifolia leaf shape is highly variable.


©2010 Keir Morse

Description

, 5-24" tall, with solitary stems supporting 2-4 pairs of , often heart-shaped leaves. Lowermost leaves are largest and long-, becoming smaller and usually higher on the stem. Leaves typically with coarsely margins. Flowerhead (almost always single, sometimes 2 or 3) with 9-15 rays with shallow on their ends and numerous disk flowers in central button. are with long spreading hairs and somewhat rounded to pointed.

Field Marks

Solitary yellow composite flower with opposite heart-shaped leaves.

© Al Schneider

A perennial plant lives and blooms for many years.

phyllaries -- Leaflike bracts covering the flowers before opening and remaining under the flower after it opens. Also called "bracts". Only used with the sunflower family (Asteraceae).

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

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.

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

Like the teeth on a saw, leaves and other surfaces can have toothed edges.

In an opposite leaf arrangement the leaves come in pairs with one leaf on each side of a stem.

sessile -- attached without a stalk. For example, a leaf that clasps the stalk. A petiolate leaf has a stalk.

petiole -- the stalk of a leaf.

stalk -- The supporting structure of an organ. Examples of stalks are stem, peduncle, petiole, ...

cordate -- heart-shaped.
subcordate -- somewhat heart-shaped.