Species category

Weed

Common name

smooth distaff thistle

Diagnostic characters

Identification notes

AchenesAchene:
A dry, hard, one-chambered, one-seeded indehiscent fruit, as in buckwheat (Fagopyrum) or sunflower (Helianthus). The fruit wall is not united with the seed coat.
are dimorphic, both obpyramidal, the four ridges forming sharp points near the apexApical:
The distal end of the fruit or seed away from the point of attachment or attachment scar.
, margins between ridge points dentate; scar lateral, along ridge, rugulose. Outer achenesAchene:
A dry, hard, one-chambered, one-seeded indehiscent fruit, as in buckwheat (Fagopyrum) or sunflower (Helianthus). The fruit wall is not united with the seed coat.
epappose, dark brown, strongly rugoseRugose:
Having veinlets sunken and areas in between raised. Wrinkled.
; scar depressed obovateObovate:
Inverted egg shaped with apical end the broadest.
. Inner achenesAchene:
A dry, hard, one-chambered, one-seeded indehiscent fruit, as in buckwheat (Fagopyrum) or sunflower (Helianthus). The fruit wall is not united with the seed coat.
smooth and light brown near base, rugulose and dark brown towards apexApical:
The distal end of the fruit or seed away from the point of attachment or attachment scar.
; scar obovateObovate:
Inverted egg shaped with apical end the broadest.
; pappusPappus:
Modified calyx in Asteraceae, composed of hairs, bristles, awns, or scales. The pappus-like structure attached to milkweed seeds is termed a coma. 
of several rows of narrow scales, persistent.

Noxious weed seed categories

State Noxious Weed: California 

AOSA examination list

Not included

Nomenclature