Coulter's horseweed is an erect, glandular-pubescent
annual with densely soft-hairy herbage and a simple stem paniculately
branched above growing to some 40" tall. The leaves are narrowly
oblong from 3/4" to 3" long, coarsely toothed or shallowly
spreading-lobed, the lowest leaves petioled and the upper cauline sessile
and ± clasping, villous or hirsute. The numerous small
heads are on peduncles to 3/8" long. The involucres are approximately
1/8" high and slightly more than that in diameter, and have phyllaries
that are linear-attentuate and densely glandular with green mid-veins.
There are as many as 125-250 ray flowers without ligules and 5-15 disk
flowers with soft whitish pappi. Coulter's horseweed occupies generally
disturbed places below 3000', occasionally in most flats in coastal
sage scrub, particularly in the Imperial Valley and Channel Islands,
blooming from May to October.
Click here for Latin name derivations: 1) Laennecia
Pronunciation: lee-NEE-see-a KOLE-ter-eye.
Formerly Conyza coulteri.
Click here for Botanical