Isocoma coronopifolia

(A. Gray) Greene

Erythea 2: 111. 1894

Common names: Common jimmyweed
Synonyms: Isocoma coronopifolia var. pedicellata (Greene) G. L. NesomIsocoma pedicellata unknown
Basionyms: Linosyris coronopifolia A. Gray
Treatment appears in FNA Volume 20. Treatment on page 444. Mentioned on page 440.
Herbage usually glabrous, leaves never stipitate-glandular, almost always resinous. Leaf blades oblanceolate, 15–30(–50) mm, margins usually pinnatifid (lobes in 1–3 pairs, spreading, linear, apically spinescent), sometimes entire or only proximal leaves pinnatifid. Involucres 5–6(–7) × 2.5–4 mm. Phyllary apices green to greenish yellow or yellowish (markedly thickened), not aristate, slightly or not gland-dotted, without resin pockets. Florets 12–15; corollas 4.5–6 mm. Cypsela ribs not forming hornlike extensions. 2n = 12.

Phenology: Flowering (May–)Jun–Oct.
Habitat: Alkaline sandy flats, matorral, shrublands
Elevation: 200–500 m

Distribution

V20-1021-distribution-map.gif

Tex., Mexico (Coahuila, Nuevo León, Tamaulipas).

Discussion

Populations with at least the distal leaves entire have been called Isocoma pedicellata, and these apparently segregate geographically, at least to some extent (G. L. Nesom 1991c). Some plants have both entire and pinnatifid leaves; the distinction does not appear to warrant formal recognition.

References

None.

Lower Taxa

No lower taxa listed.