Weed
diffuse knapweed, white knapweed
AcheneAchene:
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.
ObovateObovate:
Inverted egg shaped with apical end the broadest.
Brown to green-black with yellow longitudinal stripes
Smooth
Scar is lateral but near the base. Short pappusPappus:
Modified calyx in Asteraceae, composed of hairs, bristles, awns, or scales. The pappus-like structure attached to milkweed seeds is termed a coma. 
(disc flowers) or none (ray flowers).
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. from this species are somewhat dimorphic, evident in the presence or absence of a minute pappusPappus:
Modified calyx in Asteraceae, composed of hairs, bristles, awns, or scales. The pappus-like structure attached to milkweed seeds is termed a coma. . 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. oblong to obovateObovate:
Inverted egg shaped with apical end the broadest., compressed; smooth lustrous, sparsely pubescentPubescent:
Having hairs.
, brown to blackish-green with light colored longitudinal lines, area around scar light. ApicalApical:
The distal end of the fruit or seed away from the point of attachment or attachment scar.
rim brown, horizontal. Scar in lateral hook-shaped depression.
State Noxious Weed: Arizona, California, Colorado, Idaho, Montana, Nebraska, Nevada, North Dakota, Oregon, Utah, Washington, Wyoming
Not included
For more information, see ISMA fact sheet.
Asteraceae
Centaurea diffusa Lam.
Acosta diffusa (Lam.) Soják
