Telegraphweed

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.

Annuals, biennials, or short-lived perennials, 10–250 cm (atypical, spring-blooming, dwarf dune plants have short stems; perennating from proximal stem nodes in south; aromatic); taprooted. Stems 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. Leaves: 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. Heads 10–110+, in corymbiform arrays, becoming paniculiform with age, branches ascending, usually relatively short compared to plant height. Peduncles 10–65 mm, sparsely to densely hispido-strigose, densely stipitate-glandular; bracts 0–3, linear-lanceolate to linear, reduced distally. Involucres campanulo-hemispheric, 6–9 mm. Phyllaries in 4–6 series, linear-lanceolate, unequal, margins scarious, faces strigose, densely stipitate-glandular. Ray florets 20–40; laminae 5–8 × 1–2 mm. Disc florets 30–75; corollas 4–6 mm, lobes 0.5–0.8 mm. Cypselae 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. 2n = 18.

Heterotheca floribunda Bentham

Heterotheca grandiflora is a species of flowering plant in the family Asteraceae known by the common name silk-grass goldenaster or telegraphweed. It is native to the southwestern United States (California, Nevada, Utah, Arizona) and northwestern Mexico (Baja California), but it can be found in other areas as an introduced species, such as Hawaii. It is often a roadside weed even where it is native.

Heterotheca grandiflora is a tall, bristly, glandular plant exceeding a meter (40 inches) in height and densely foliated in hairy to spiny toothed or lobed leaves. Leaves are smaller and more widely spaced toward the top of the stem, which is occupied by an inflorescence of bright yellow daisy-like flower heads. The disc and ray florets drop away to leave a spherical head of achenes, each with a long white pappus.

Heterotheca grandiflora

Closeup of flower

Closeup of flower gone to seed

Field of Heterotheca grandiflora