Xanthocephalum gymnospermoides

(A. Gray) Bentham & Hooker f.

Gen. Pl. 2: 249. 1873

Common names: San Pedro matchweed
Synonyms: Grindelia gymnospermoides (A. Gray) Ruffin
Basionyms: Gutierrezia gymnospermoides A. Gray
Treatment appears in FNA Volume 20. Treatment on page 437.
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Plants 30–150 cm, herbage glabrous. Stems usually 1, erect. Leaf blades 40–100 mm, bases narrowly decurrent, margins entire to spinulose-toothed, faces resinous. Heads usually in tight to loose, corymbiform arrays, rarely borne singly. Peduncles: ultimate 1–40 mm, minutely stipitate-glandular. Phyllaries minutely stipitate-glandular. Ray corollas 4–11 mm. Pappi (ray) 0, outer disc 0 or minute crowns, inner nearly 0 or minute crowns, sometimes lacerate or with awnlike scales 0.2–0.8 mm, rarely with ring of persistent, 15–20, antrorsely ciliolate bristles ca. 1.4 mm. 2n = 12.

Phenology: Flowering (Jul–)Aug–Oct.
Habitat: Meadows, stream bottoms, ditches, grasslands, areas of oak-pine or pine woodlands, usually in habitats at least intermittently wet
Elevation: 1100–2700 m



Ariz., Tex., Mexico (Chihuahua, Durango, Jalisco, Sonora, Zacatecas).




Lower Taxa

No lower taxa listed.