familyAsteraceae
genusXanthocephalum
Xanthocephalum gymnospermoides
Gen. Pl. 2: 249. 1873.
Common names: San Pedro matchweed
Basionym: Gutierrezia gymnospermoides A. Gray
Synonyms: Grindelia gymnospermoides (A. Gray) Ruffin
Treatment appears in FNA Volume 20. Treatment on page 437.
Revision as of 01:26, 27 July 2019 by FNA>Volume Importer
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.