ID Characteristics
This plant is in the Asteraceae - the aster family.
Spiny goldenweed ranges from the Canadian prairies south to Arizona, New Mexico, and California. As might be expected of a plant that can grow in such divergent conditions, it is highly variable, varying in size (to 3 feet in some varieties) and hairiness. The text below describes plants found in the Rincon Valley around Academy Village. Those interested in technical details should consult the Flora of North America discussion. Our plants are variety spinulosus.
Spiny goldenweed is a small perennial, sometimes woody at the base, that typically grows to 8-12 inches with a similar spread. It has a symmetrically rounded form with flowers appearing at the ends of the stems.
The alternate leaves are slender, up to an inch long but not more than 1/4 inch wide. There are several short lobes along the length of the leaf, each ending in a small white bristle (the spines of "spiny" goldenweed). The leaves often turn upward toward the stem and are often covered with woolly hairs. At flowering, the lower leaves may wither and brown.
Leaves of spiny goldenweed are often smaller near the top of the plant and usually without lobes. They still have several white bristles on each side.
The flower head has both yellow ray and yellow disc flowers. Each ray petal is about 3/8 inch long with the whole flower head just under an inch wide. The petals appear pointed on the end, though each ends in 3 small lobes.
The underside of the flower head is made of phyllaries of several different lengths, each ending in a white bristle (more "spines").
Each flower head matures into a small, rounded seed head only half an inch wide.The seeds end in many bristles of different lengths, usually longer than the seed. Several seeds are visible to the left of the photo. Please click to enlarge.
Once the seeds drop off, the phyllaries - and their spine-like white bristles - remain, now bent backward. The center of the head is the receptacle that once held the individual flowers. One seed remains, showing that the white bristles are much longer than the seed.