Heterotheca grandiflora
Heterotheca zionensis
silk-grass goldenaster, telegraph weed
Zion false goldenaster, Zion goldenaster
1–5+, ascending to erect (strict, 0.9–1.7 cm diam., only distal lateral branches developing in larger plants), moderately to densely hispido-strigose, more so proximally, moderately to densely stipitate-glandular, more so distally.
1–20+, ascending to erect (sometimes ± brittle, green to light-green proximally, greenish to whisith distally), moderately to densely hispid and short-strigose, abundantly long-hispid, sometimes becoming moderately hairy and densely stipitate-glandular distally.
basal and proximal cauline petiolate (petioles 3–7 cm, bases auriculate-clasping), blades ovate or elliptic to oblong, 50–80 × 20–30 mm, margins flat or somewhat undulate, coarsely serrate to serrulate or entire, proximally long-ciliate, apices acute, faces moderately to densely long-hispido-strigose;
distal sessile, blades oblong-lanceolate to lanceolate, 20–40 × 20–30 mm, reduced distally, margins often undulate, coarsely serrate.
proximal cauline petiolate to subsessile, blades (whitish when fresh, drying grayish to whitish green) narrowly to broadly oblanceolate, 15–45 × 5–8 mm, bases attenuate, margins flat, entire, strigoso-ciliate, proximally long-hispido-strigose, apices acute, faces densely hispido-strigose, sparsely to moderately stipitate-glandular;
distal sessile, blades narrowly to broadly ovate or lanceolate to oblong, 10–20(–30) × 2.5–7.3 mm, reduced distally, densely to very densely hispido-strigose, moderately to densely stipitate-glandular beneath hairs.
10–65 mm, sparsely to densely hispido-strigose, densely stipitate-glandular;
bracts 0–3, linear-lanceolate to linear, reduced distally.
9–41 mm, moderately to densely hispido-strigose, moderately to densely stipitate-glandular;
bracts 0–5, proximal lanceolate, much reduced distally;
linear to oblanceolate, leaflilke bracts sometimes subtending heads.
campanulo-hemispheric, 6–9 mm.
cylindro-turbinate to narrowly campanulate, (4.3–)5–7.5(–8) mm.
20–40;
laminae 5–8 × 1–2 mm.
8–18(–23);
laminae 6.5–13 × 1–1.7 mm.
30–75;
corollas 4–6 mm, lobes 0.5–0.8 mm.
(11–)16–44(–62);
corollas ± ampliate, (3.5–)4.5–7 mm, lobes 0.4–0.7 mm, sparsely pilose (hairs on lobes 0.1–0.3 mm).
in 4–6 series, linear-lanceolate, unequal, margins scarious, faces strigose, densely stipitate-glandular.
in 5–6 series, lanceolate, unequal (outer lengths 1/5–1/4 inner), margins scarious, faces either sparsely hispido-strigose and densely stipitate-glandular or moderately hispido-strigose and sparsely to moderately stipitate-glandular.
10–110+, in corymbiform arrays, becoming paniculiform with age, branches ascending, usually relatively short compared to plant height.
7–27(–46) in corymbiform arrays, branches ascending.
dimorphic, (ray) 2–5 mm, faces glabrous or slightly strigose on angles, (disc) 4–6 mm, faces moderately to densely strigose;
pappi 0 (ray) or (disc) stramineous to rusty brown, outer bristles 0.4–0.7 mm, inner 6–9 mm, longest weakly clavate.
monomorphic, obconic, compressed, 1.5–3(–4) mm, ribs ca. 10, faces moderately strigose;
pappi off-white, outer of linear scales 0.25–0.5 mm, inner of 25–40 weakly clavate bristles 4–7 mm.
= 18.
= 18, 36.
Heterotheca grandiflora
Heterotheca zionensis
Heterotheca grandiflora is common in California, rare and probably introduced in Arizona, Nevada, and Utah, and introduced in Hawaii. Rosette plants can bloom in the spring.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Of conservation concern.
Heterotheca zionensis grows in eastern Arizona and Utah; it is introduced and established in the vicinity of Las Cruces, New Mexico; chance introductions (likely emphemeral) have been found in Moffat County, Colorado, and Franklin County, Idaho. Whitish-appearing stems and leaves readily distinguish H. zionensis from H. villosa var. scabra, which frequently occurs sympatrically in southern Utah and northern Arizona. The species could be confused also with H. villosa var. pedunculata which has more hairs/mm2 on its leaves and few or no glands on its phyllaries. It could also be confused with narrow, smaller-leaved forms of H. fulcrata var. amplifolia, which has a few petiolate-ovate bracts subtending the heads.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
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iNaturalist
USDA Plants Database
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