Grindelia arizonica
Grindelia havardii
Arizona gumweed, cutleaf gumweed, New Mexican gumweed
Havard's gumweed
erect, stramineous to reddish, glabrous.
erect, stramineous to pinkish, usually villosulous to hirtellous and/or stipitate-glandular, sometimes glabrate.
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 mostly ovate to oblong, (7–)15–30(–55) mm, lengths 2–4 times widths, bases ± clasping, margins crenate (teeth mostly 3–5 per cm, blunt, resin-tipped), apices obtuse to acute, faces usually hirtellous and little, if at all, gland-dotted, sometimes glabrate (then gland-dotted).
usually campanulate to obconic, sometimes hemispheric, 4–11 × 8–17 mm.
broadly urceolate to globose, 8–13 × 12–22 mm (often subtended by leaflike bracts).
0 or 8–26;
laminae (5–)7–10 mm.
18–25;
laminae 8–11 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 5–6 series, reflexed to spreading, linear to lanceolate, apices subulate to terete, ± recurved to straight (terminal setae incurved), moderately to strongly resinous.
usually in corymbiform to paniculiform arrays, rarely borne singly.
borne singly or in open to crowded, corymbiform arrays.
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 to light brown, (2–)3–3.5 mm, apices smooth to minutely coronate, faces smooth or striate (angles ± ribbed);
pappi of 2 ± straight, usually smooth (apices usually dilated), setiform awns 4–7 mm, ± equaling disc corollas.
= 12.
= 12.
Grindelia arizonica
Grindelia havardii
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
