Simsia

Annuals, perennials, or subshrubs [shrubs], 20–400 cm. Stems erect or ascending [decumbent], sparingly to freely branched. Leaves cauline; opposite (proximal) or alternate [whorled]; petiolate (petioles often ± winged, often with expanded bases, those bases sometimes fused to form nodal “discs”) [sessile]; blades 3-nerved from bases, mostly deltate to ovate [linear], sometimes 3- [5-]lobed[pinnatifid], bases cordate to cuneate, ultimate margins entire or toothed, faces hirsute, hispid, pilose, puberulent, scabrous, or scabro-hispid [sericeous], often gland-dotted or ± stipitate-glandular to glandular-puberulent. Heads radiate [discoid], borne singly or in 2s or 3s, or in tight to loose, corymbiform [paniculiform] arrays. Involucres campanulate [ovoid-campanulate to urceolate], 5–16[–22] mm diam. Phyllaries persistent, [11–]13–43[–66] in 2–4 series (tightly appressed to broadly reflexed, unequal to subequal). Receptacles low-convex, paleate (paleae conduplicate, ± enclosing cypselae). Ray florets [0–]5–21[–45], styliferous and sterile; corollas orange-yellow [lemon-yellow, pink, purple, or white]. Disc florets [12–]13–154[–172], bisexual, fertile; corollas concolorous with rays (usually turning purple apically), tubes (often glandular-hairy) shorter than throats, lobes 5, ± triangular (anthers black, yellow, or yellow proximally and bronze or purple distally; style branches relatively slender, apices sometimes attenuate). Cypselae flattened, thin-margined [thickened, biconvex] (shoulders minute to conspicuous, faces glabrous or hairy); pappi 0, or fragile or readily falling, of 2 ± subulate scales [plus 4–12 shorter scales]. x = 17.

Distribution

sw United States, Mexico, West Indies (Jamaica), Central America, South America.

Discussion

Species 20 (2 in the flora).

Selected References

Spooner, D. M. 1990. Systematics of Simsia (Compositae–Heliantheae). Syst. Bot. Monogr. 30: 1–90.

Lower Taxa

Simsia calva, Simsia lagasceiformis

Key

1	Perennials or subshrubs (roots fusiform-thickened); ray florets 8–21, corollas light orange-yellow (abaxial faces often brown- or purple-lined, or wholly brown or purple); disc florets (26–)90–154; anthers usually yellow, rarely black	Simsia calva
1	Annuals (rarely persisting, taprooted or fibrous rooted); ray florets 5–10, corollas orange-yellow; disc florets 13–27; anthers yellow proximally, usually purple to bronze distally	Simsia lagasceiformis