L. D. Gottlieb in Flora of North America (vol. 19, 20 and 21)
, 5-30 cm; taprooted.
1-3, erect or ascending, branched from bases; distal stems, branches, and involucres conspicuously dotted with short, stipitate, flat-topped glands that resemble tacks.
basal and cauline; alternate; sessile; basal blades pinnately lobed (lobes narrow, linear, often delicate, spreading, margins entire, smooth); distal reduced to linear, entire bracts.
borne singly or in open, cymiform arrays.
(1-3 cm) not inflated, not bracteate.
of 8-16, reflexed, unequal bractlets (lengths to
campanulate, 5-12+ mm diam.
12-20 in 1 series, linear-lanceolate, equal, margins scarious, apices acute
flat, smooth, bristly, epaleate (each floret subtended by 1 fine, capillary bristle).
ca. 25; corollas white or yellow (showy).
tan to brown, fusiform, beaked, ribs 5, separated by longitudinal grooves, faces glabrous or scabridulous;
(borne on denticulate cups at beak tips) falling (together), of 50-60+, white, basally connate, smooth bristles 5-8(-9) mm in 1 series.
Species within checklist:
Tres Rios and the Phoenix Four Rivers