Pectis prostrata

Annuals, 1-30 cm (across); herbage not scented. Stems prostrate to ascending (often mat-forming, densely leafy, especially distally), puberulent (in lines or throughout). Leaves linear to narrowly oblanceolate, 10-40 × 1.5-7 mm, margins with 4-12 pairs of setae 1-3 mm, faces glabrous (abaxial densely dotted with round oil-glands 0.1-0.3 mm). Heads borne singly or in congested, (leafy) cymiform arrays. Peduncles 1-2 mm. Involucres campanulate, cylindric, or ellipsoid. Phyllaries coherent (falling together), oblong to obovate, 5-8 × 1-3 mm (often dotted in submarginal rows and sometimes along midribs with elliptic oil-glands 0.1-0.3 mm). Ray florets 5; corollas 2.5-3.5 mm (scarcely surpassing phyllaries). Disc florets 3-17; corollas 1.8-2.5 mm (2-lipped). Cypselae 2.5-4.5 mm, strigillose; pappi of 2 (ray) or 5 (disc) lanceolate scales 1.5-2.5 mm. 2n = 24.

Flowering Jul-Nov. Open sites in deserts, grasslands, oak-pine-juniper woodlands, roadsides; 0-2000 m; Ariz., Fla., La., N.Mex., Tex.; Mexico; West Indies; Central America.

The development of roads and highways has created ideal habitats for Pectis prostrata. Its range appears to be expanding along the coasts of Florida; it was discovered in Louisiana relatively recently. It can be expected to spread along the Gulf Coast and perhaps northward along the Atlantic Coast as well. Autogamy has apparently assisted P. prostrata to spread rapidly as suitable new habitats have become available.

FNA 2006, Wiggins 1964, Kearney and Peebles 1969

Duration: Annual Nativity: Native Lifeform: Forb/Herb General: Diffuse annual branching from base, 1-30 cm across, with prostrate to ascending stems, often mat-forming, densely leafy and puberulent. Leaves: Linear to narrowly oblanceolate, 10-40 mm long by 1.5-7 mm wide, margins with 4-12 pairs of bristles 1-3 mm near base, faces glabrous, dotted below with round oil glands 0.1-0.3 mm. Flowers: Heads borne singly or in congested cymiform arrays on peduncles 1-2 mm, surpassed by subtending leaves; involucres campanulate, cylindric to ellipsoid; phyllaries coherent, oblong to obovate, 5-8 mm long by 1-3 mm wide, dotted in submarginal rows of elliptic oil glands, 0.1-0.3 mm; ray florets 5, yellow, corollas 2.5-3.5 mm, scarcely surpassing phyllaries; disc florets 3-17, about 2 mm long. Fruits: Cypselae 2.5-4.5 m, stiff hairs, with pappus of (2 ray and 5 disc) lanceolate scales, 1.5-2.5 mm long. Ecology: Found in open sites in deserts, grasslands, oak-pine-juniper woodlands, roadsides; sea level to 6,500 ft (0-1981 m); flowers July-November. Distribution: Southern US, from AZ, s NM, TX, to GA and FL; south through MEX to c America. Notes: An ascending or prostrate annual, growing singly, or with few to many plants growing together in bunches, forming patches or sometimes dense groundcover. Distinguished by having opposite, dark-green, linear leaves with hair-like projections from the margins, 5 rays and very short peduncles (stems below heads) and phyllaries joined and close together, falling as a unit. Notably, Pectis species have C4 photosynthetic pathways which accounts for why they inhabit such hot, dry sites. Ethnobotany: Unknown Etymology: Pectis is from the Greek pecteo, to comb, while prostrata means prostrate. Synonyms: Pectis multisetosa, P. prostrata var. urceolata Editor: SBuckley 2010, FSCoburn 2015