Grindelia arizonica
Grindelia adenodonta
Arizona gumweed, cutleaf gumweed, New Mexican gumweed
lonestar gumweed
erect, stramineous to reddish, glabrous.
erect, stramineous to purple, proximally sparsely hirtellous to glabrate, distally ± hirtellous to villosulous.
blades oblong, spatulate, or oblanceolate to linear, 15–45(–85) mm, lengths mostly 3–8 times widths, bases ± cuneate, margins serrate (teeth from bases to apices or mostly toward apices, apiculate to setose), entire, or (proximal leaves) pinnately lobed to coarsely toothed, apices acute, faces glabrous (or scabridulous near margins), sparsely, or not at all, gland-dotted.
blades ovate or ± triangular to oblong or obovate, 15–60(–90) mm, lengths 1.5–3(–4+) times widths, bases ± clasping, margins ± crenate (teeth 8–14 per cm, blunt, resin-tipped), apices obtuse to acute, faces usually hirtellous to scabridulous and glandular (glands usually in pits, sometimes sessile, seldom stipitate), sometimes glabrate.
usually campanulate to obconic, sometimes hemispheric, 4–11 × 8–17 mm.
± urceolate to hemispheric, 8–12 × 10–20 mm (usually subtended by leaflike bracts).
0 or 8–26;
laminae (5–)7–10 mm.
20–27;
laminae 8–12 mm.
in 4–6 series, linear to ± lanceolate, usually appressed, sometimes weakly reflexed or spreading, apices slightly recurved to straight, subulate or acuminate to deltate, slightly to strongly resinous.
in 4–6 series, spreading to appressed, lanceolate to linear, apices subulate, hooked to ± recurved or nearly straight, moderately resinous.
usually in corymbiform to paniculiform arrays, rarely borne singly.
in open, corymbiform to paniculiform arrays or borne singly.
stramineous to brown, 2.5–4 mm, apices coronate or knobby, faces striate to furrowed;
pappi of 2–4 straight or weakly contorted, smooth setiform awns or subulate scales 2–5 mm, shorter than disc corollas.
stramineous or brownish, 3–4.5 mm, apices ± coronate to knobby, faces (outer) rugose (not transversely fissured; angles ± ribbed) or (inner) striate;
pappi of 2 straight or weakly contorted, smooth (apices dilated), bristles or setiform awns 5–6 mm, equaling or surpassing disc corollas.
= 12.
= 12.
Grindelia arizonica
Grindelia adenodonta
Plants of Grindelia arizonica with ± hemispheric involucres and apices of phyllaries ± subulate (versus lance-acuminate to deltate) have been called var. neomexicana (or G. neomexicana). Plants known as var. stenophylla differ from typical G. arizonica in having leaf margins toothed mostly toward apices (versus toothed from bases to apices). Plants of G. arizonica (from northern Arizona, southwestern Colorado, and southeastern Utah) with leaf margins pinnately lobed to ± laciniate or coarsely dentate have been called G. laciniata. Some herbarium specimens that have been identified as G. aphanactis (see 4. G. squarrosa) appear to be discoid plants of G. arizonica. Hybrids between G. arizonica and G. squarrosa have been recorded from Colorado and Utah.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
SW CO Wildflowers
WildflowerSearch
iNaturalist
USDA Plants Database
