Plants perennial (rarely annual); cespitose. Culms 0.5-8 m, weakly lignified, erect, arching, climbing, or decumbent, rooting at the nodes. Sheaths open; ligules membranous, sometimes ciliate; pseudopetioles sometimes present; blades linear to ovate, bases slightly to strongly asymmetric. Inflorescences open or contracted panicles, rachises usually visible, even distally, spikelets attached obliquely to the pedicels; disarticulation below the glumes. Spikelets subglobose to globose, with 2 florets. Glumes membranous, apices lanate pubescent, abruptly apiculate; lower glumes 1/3-2/3 as long as the spikelets, 5-13-veined, bases saccate, margins overlapping; upper glumes about as long as the upper florets, not saccate, 7-15-veined; lower florets sterile or staminate; lower lemmas membranous, apices lanate pubescent, abruptly apiculate; lower paleas present, sometimes reduced; upper florets stipitate, bisexual, appearing to be mucronate or acuminate; upper lemmas indurate, usually broadly elliptic to obovate, margins enclosing the edges of the paleas, apices obtuse, somewhat woolly pubescent, usually dark brown at maturity; upper paleas similar to the lemmas, but saccate below and gibbous above. Caryopses plano-convex, ovoid, or nearly orbicular; embryo about 1/2 as long as the caryopses; hila oblong to nearly round. x = 9. Name from the Greek lasios, woolly, and akis, point, referring to the tuft of wool at the apex of the spikelets.

Lasiacis is a neotropical genus of 16 species that extends from southern Florida to Peru and Argentina. Two species are native to the Flora region. The shiny black color of its mature florets and the oil-filled cells of the inner epidermes of the glumes and sterile lemmas distinguish Lasiacis from all other grasses. Birds are a common dispersal agent.

In Lasiacis the upper florets appear to be mucronate or acuminate. The mucro or acuminate apex is formed by the tuft of hairs at the apex of the upper floret.

1.   Lasiacis divaricata (L.) Hitchc.

Plants perennial; cespitose. Culms (0.5)1-5(7) m long, arching, clambering over brush or bending to the ground if unsupported. Sheaths mostly glabrous, margins and throats ciliate; ligules 0.8-13 mm, glabrous or ciliate; blades (3)5-12(16) cm long, 3-20(30) mm wide, linear-lanceolate to narrowly lanceolate, lower blades often deciduous. Panicles 2-12(20) cm; branches to 12 cm, with widely-spaced spikelets; lower branches usually reflexed; upper branches widely spreading. Spikelets 3.5-4.5 mm, obovate. Lower glumes 1.2-2.5 mm; lower florets sterile; upper florets 3.4-4 mm long, 1.9-2.4 mm wide, whitish to brown at maturity; anthers about 2 mm, white; stigmas purple. Caryopses whitish. 2n = 36.

Lasiacis divaricata is a Caribbean species. Its range extends from Florida through the West Indies to Mexico, Panama, and northern Venezuela. In Florida, it usually grows in hammocks, but occasionally in pinelands. The whitish to brown upper florets are unusual in the genus.

Plants in the Flora region belong to Lasiacis divaricata var. divaricata, which differs from the other two varieties in having panicles with fewer spikelets and panicle branches that are usually reflexed.

2.   Lasiacis ruscifolia (Kunth) Hitchc.

Plants perennial; cespitose. Culms 1-8 m long, 5-12 mm thick, hollow, arching or clambering. Sheaths glabrous, puberulent, or hispid with papillose-based hairs, margins ciliate; ligules 0.2-1 mm, glabrous or ciliate; blades 2-16 cm long, 8-56mm wide, ovate to ovate-lanceolate. Panicles 2-22 cm; lower branches to 9 cm, divergent. Spikelets 2.6-4 mm, globose; lower glumes 1.2-2.2 mm, 9-13-veined; lower florets sterile; upper glumes 11-13-veined; upper florets 2.8-3.6 mm long, 2-2.9 mm wide, dark brown to grayish-black at maturity; upper lemmas usually with a distinct shelf at the base, from which a sterile projection often arises; upper paleas usually deeply concave; anthers 1.4-2.3 mm, white; stigmas white. Caryopses 2-2.5 mm. 2n = 36.

The range of Lasiacis ruscifolia extends from southern Florida to Peru. Plants in the Flora region belong to Lasiacis ruscifolia (Kunth) Hitchc. var. ruscifolia, which differs from L. ruscifolia var. velutina (Swallen) Davidse in being scabrous or puberulent, rather than velutinous, on the panicle branches.