Al Schneider's Rocky Mountains Plant Descriptions

Arrowleaf Groundsel
Senecio triangularis
Aster family (Asteraceae)

Groundsels have a rich folk lore including fairies using the plants to travel from place to place. Arrowleaf Groundsel is distinguished by its large triangular leaves. It occurs at higher elevations and moister soils than Tall Western Groundsel (S. integerrimus). Senecio serra is very similar to Senecio triangularis: they both grow in wet habitats, have the same growth habits, the flowers are very similar, etc. But they can easily be told apart by their leaf shape; S. serra leaves are not triangular.

Thomas Drummond collected this plant, probably on his second trip to the United States in the early 1830s. The plant was named by William Hooker, Drummond's mentor.


©2009 Keir Morse

Description

, 2-5' tall, often growing in large clusters in damp to wet areas. Leafy to of plant, or sparingly hairy near . Leaves , 2-8" long, about 1/4 as wide, , triangular, and sharply on margin. Several yellow flowerheads in a flattened cluster, each with 6-12 yellow (about 1/2" long ) surrounding yellow flowers. is an .

Field Marks

Tall plant with yellow flat-topped flowerheads and arrow-shaped leaves.

© Al Schneider

node -- The point at which there is attached growth, as in the place where each leaf is attached.

A perennial plant lives and blooms for many years.

The apex is the tip or the furthest point from the attachment.

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.

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

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

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

disc flowers are those in the center of a sunflower or daisy. Not a ray flower.

alternate -- leaves alternate along the main stem and are attached singly.

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