Florida Chinchweed

Reports of Pectis linearifolia from Jamaica were based on misidentifications of diminutive, short-peduncled individuals of P. glaucescens (D. J. Keil 1986). In Florida, P. linearifolia and P. glaucescens are largely allopatric; they occasionally occur in mixed populations. No hybrids are known.

Annuals, 4–40 cm; herbage lemon-scented. Stems decumbent to erect (very leafy), glabrous or puberulent (in decurrent lines). Leaves linear, 10–50 × 1–3 mm, margins with 2–6 pairs of setae, faces glabrous (abaxial dotted submarginally with round oil-glands 0.2–0.5 mm). Heads borne singly or in congested, (leafy) cymiform arrays. Peduncles 0–1 mm. Involucres narrowly campanulate to cylindric. Phyllaries distinct, linear or linear-oblanceolate, 5–6 × 1–1.5 mm (dotted with scattered, elliptic oil-glands 0.4–0.5 mm). Ray florets 5; corollas 4.5–5.5 mm. Disc florets 4–10; corollas 2.5–3 mm (2-lipped). Cypselae 2.25–3.25 mm, puberulent; pappi (ray and disc similar) of 2–5 antrorsely barbed bristles or awns 1.5–2.5 mm plus shorter, barbellate scales. 2n = 48.

Pectis linearifolia Urban, vSymb. Ant. 5: 276. 1907
PectisUnifoliaGriseh.Fl.Bnt.Vf.Ind.37S. 1861. Not P. linifolia U 1759. Pectis ciliaris Fernald, Proc. Am. Acad. 33: 66. 1897. Not P. ciliaris L. 1759.
A leaf Jannual; stem erect or ascending, 1-4 dm. high, with ascending or spreading branches, puberulent along two decurrent lines; leaves narrowly linear, 1.5-3 cm. long, 1-2 mm. wide, with more or less revolute margins, scarcely cormate, with 3-6 pairs of bristles towards the base; glands in a single row along each margin; heads 1-5, clustered at the ends of the branches, subsessile or on peduncles less than 4 mm. long; involucre 4.5-5 mm. high, 2-3 mm. broad; bracts lance-linear, acute or obtuse; ray-flowers 5; ligules 2 mm. long; diskflowers 6 or 7; corollas about 2.5 mm. long; achenes 2.8-3 mm. long; squamellae of the diskflowers 5, of the ray-flowers 2, narrowly lanceolate, aristate-attenuate, as long as the diskcorollas.
Type locality: Tampa, Florida. Distribution: Florida and Jamaica.

Pectis linearifolia, the Florida cinchweed, is a summer blooming annual plant in the genus Pectis. Although the plant exhibits the ecology of an introduced non-native plant, it is known with certainty only from south Florida, and must be regarded as native in view of current distribution data. It has also reputedly been found in Jamaica, but the Jamaican reports are evidently somewhat doubtful.