Al Schneider's Rocky Mountains Plant Descriptions

Pineappleweed
Matricaria discoidea
Aster family (Asteraceae)

This plant is found through all the cooler states, along roadsides and in waste places, often on moist or sandy ground. Pineapple Weed (Matricaria discoidea) has been used as a medicinal and aromatic plant by Native American tribes, but it is also considered a weed by ranchers and others. It is a northwestern North American native that has spread to eastern and northern North America. Several respected botanical groups erroneously indicate that M. discoidea is an introduced species. It actually is a North American native which is now an invasive species in Europe.


©2003 Krzysztof Ziarnek

Description

or hairy plants with stems 4-16" tall, branched from the base or not. Leaves 2-3 times with short , very narrow ultimate divisions. Flowerheads distinctively cone-shaped, several to numerous, in clusters. are saucer-shaped, wider than high with about equal in height and somewhat over-lapping. Disk flowers are 4-. absent. with 4 on one face, smooth on the other.

Field Marks

Flowerheads cone-shaped with minute petals and very finely cut leaves.

© Al Schneider

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

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

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.

ribbed -- having prominent, narrow parallel protrusions that extend over most of its length or circumference.

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

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.

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

lobe -- Being divided by clefts.