familyAsteraceae
genusXanthocephalum
Xanthocephalum gymnospermoides
Gen. Pl. 2: 249. 1873.
Common names: San Pedro matchweed
Illustrated
Basionym: Gutierrezia gymnospermoides A. Gray Smithsonian Contr. Knowl. 5(6): 79. 1853
Synonyms: Grindelia gymnospermoides (A. Gray) Ruffin
Treatment appears in FNA Volume 20. Treatment on page 437.
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
Distribution
Ariz., Tex., Mexico (Chihuahua, Durango, Jalisco, Sonora, Zacatecas).
Discussion
Selected References
None.
Lower Taxa
None.