Al Schneider's Rocky Mountains Plant Descriptions

Eaton's Thistle
Cirsium eatonii
Aster family (Asteraceae)

Eaton's Thistle is a very prickly native thistle with a number of local varieties. The variety shown usually has a very erect posture with narrow, hairless, shiny leaves and tight clusters of very attractive lavender flowers. The name, "Cirsium," is Greek for "dilated vein" from the bygone belief that a Thistle distillate opens clogged veins. The species name honors Daniel Eaton, Yale Botany Professor, fern specialist, and plant collector, who was the first to collect this plant for science.


©2006 Stan Shebs

Description

Long-lived, prickly , 2-5' tall, spreading from roots. and stem leaves are 3-12" long, shiny, narrowly , and sharply with spiny tips. Stem . Pink-purple-lavender flowerheads in tight clusters, comprised of flowers only. are with feathery white-brown .

Field Marks

Erect plant with tight cluster of pink flowers and very prickly leaves.

© Al Schneider

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

A perennial plant lives and blooms for many years.

pinnatifid -- A leaf shape that is pinnately lobed but not cut all the way to the axis.

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.

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.

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.

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

leaves alternate along the main stem and are attached singly.