Paspalum setaceum var. rigidifolium (Nash) D. Banks (redirected from: Paspalum rigidifolium)
Family: Poaceae
[Paspalum rigidifolium Nash]
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Plants erect to spreading. Leaves mostly cauline; blades to 30 cm long, 2.4-6.1 mm wide, conspicuously rigid, stiff, pubescent adaxially, glabrous or sparsely pubescent abaxially, margins sometimes ciliate. Panicle branches 4.8-11.3 cm; branch axes 0.7-1.1 mm wide. Spikelets 2-2.6 mm long, 1.6-1.8 mm wide, obovate to ovate, pubescent, sometimes sparsely so; lower lemmas with or without an evident midvein; upper florets 2-2.4 mm.

Paspalum setaceum var. rigidifolium grows on hammocks, sand barrens, high pinelands, and flatwoods of Georgia, Florida, and Cuba.

Perennial herb with short rhizomes or forming tufts 25 cm - 1 m tall

Leaves: mostly consisting of stem leaves, alternate, two-ranked. Sheaths open, sometimes hairy. Ligules to 0.5 mm long, membranous. Blades rigid, to 30 cm long, 2.5 - 6 mm wide, lance-shaped, flat, parallel-veined, hairy above, sometimes sparsely hairy beneath, sometimes fringed with hairs.

Inflorescence: a branched arrangement of spikelets (panicle), terminal and axillary, bearing one to six spike-like branches. Axillary panicles completely or partially enclosed by a subtending leaf sheath. Branches ascending to spreading, often bowed, 5 - 11 cm long, with spikelets mostly arranged in two rows along one side of the branch. Branch axes 0.5 - 1 mm wide, sometimes rough.

Fruit: a caryopsis, indehiscent, enclosed within the persistent lemma and palea, white, elliptic to nearly orbicular.

Culm: upright or spreading, 25 cm - 1 m long, round in cross-section, hollow. Nodes sometimes hairy.

Spikelets: paired, overlapping, arranged along one side of the inflorescence branch, appressed to the branch axis, bearing two florets, straw-colored or brown, 2 - 2.5 mm long, 1.5 - 2 mm wide, plano-convex (one side flat, the other convex), egg-shaped to reverse egg-shaped, and hairy.

Glumes:: Lower glumes absent. Upper glumes nearly equal to lower lemmas, rounded at the apex, three-veined, sometimes shortly glandular-hairy, membranous.

Lemmas:: Lower lemmas nearly equal to upper glumes, rounded at the apex, sometimes shortly glandular-hairy, membranous, three-veined, with or without an evident midvein. Upper lemmas clasping the paleas, straw-colored to brown, convex, smooth to slightly wrinkled, with rolled-up margins on the upper surface.

Paleas:: Lower paleas rudimentary or absent. Upper paleas straw-colored to brown, smooth to slightly wrinkled.

Florets:: Lower florets sterile. Upper florets bisexual, straw-colored, 2 - 2.5 mm long. Anthers three. Stigmas red.

Similar species: No information at this time.

Flowering: June to September

Habitat and ecology: Sandy areas.

Occurence in the Chicago region: native

Etymology: Paspalum comes from the Greek word paspalos, a type of millet. Setaceum means bristle-like. Rigidifolium means "having rigid leaves."

Author: The Morton Arboretum