Manyray Gumweed

Annuals, 50–150(–200) cm. Stems erect, stramineous, glabrous. Cauline leaf blades oblanceolate or lanceolate to linear, 25–40(–60) mm (distal smaller, ± appressed), lengths mostly 4–6 times widths, bases ± clasping, margins ± crenate (teeth mostly 9–15 per cm, rounded to obtuse or blunt, resin-tipped), apices acute to acuminate, faces glabrous, little, if at all, gland-dotted. Heads borne singly or in open, corymbiform arrays. Involucres broadly urceolate, 8–14 × 10–20+ mm. Phyllaries in 5–6 series, slightly spreading to appressed, linear to lance-attenuate or lanceolate, apices incurved to straight, filiform to subulate, slightly resinous. Ray florets 17–26; laminae 10–12 mm. Cypselae stramineous to reddish brown, 2–3+ mm, apices coronate to knobby, faces striate or furrowed; pappi of 2–4 straight, barbellulate or smooth (apices slightly dilated), setiform awns 3–4.5 mm, shorter than to nearly equaling disc corollas. 2n = 12.

Grindelia grandiflora, the manyray gumweed, is a North American species of flowering plants in the family Asteraceae. It is native to the south-central United States and north-central Mexico, in the states of Texas and Coahuila.

Grindelia grandiflora grows in grasslands, scrublands, ditches, and roadsides, and along streambanks. It is an annual herb sometimes as much as 200 cm (80 inches or almost 7 feet) tall. The plant usually produces numerous flower heads in open, branching arrays. Each head has 17-26 ray flowers, surrounding a large number of tiny disc flowers.