Plants annual. Culms (5)13-150 cm, usually erect, compressed, branching;
internodes hollow. Sheaths sparsely or densely hairy, particularly
distally, hairs papillose-based; ligules 0.6-3.2 mm, membranous, truncate,
erose; blades 6-25 cm long, 2-21 mm wide, glabrous or sparsely pilose on
both surfaces. Panicles 8-30 cm, with 3-100 racemose branches; branches
1-19 cm, ascending to reflexed. Spikelets 2-4 mm, distant to imbricate,
green, magenta, or maroon, with 2-5(6) florets. Glumes sometimes exceeding
the florets, linear to narrowly elliptic, acute, attenuate, or aristate; lower
glumes 1.6-4 mm, linear to lanceolate; upper glumes 1.6-3.6 mm, lanceolate;
lemmas 0.9-1.7 mm, glabrous or somewhat sericeous, acute to obtuse; paleas
glabrous or sericeous; anthers 3, 0.2-0.3 mm. Caryopses 0.8-1.2
mm long, 0.5-0.6 mm wide, nearly round in cross section, with or without a ventral
groove, apices acute to broadly obtuse.
Leptochloa panicea is a cosmopolitan species that somewhat resembles L.
chinensis, an aggressive weed that has not yet been found in the Flora
region. It differs in its sparsely to densely hairy, rather than glabrous or almost
glabrous, sheaths and blades. Two of its three subspecies grow in the Flora
region.
FNA 2003, Gould 1980
Common Name: mucronate sprangletop Duration: Annual Nativity: Native Lifeform: Graminoid General: Cespitose annual grass with erect, compressed stems, 13-150 cm long. Vegetative: Sheaths sparsely or densely hairy, particularly distally, with papillose-based hairs; ligule a ciliate membrane 0.6-3 mm long; blades elongate, 3-25 cm long, 1-7 mm wide, glabrous or sparsely pilose on both sides, apex attenuate. Inflorescence: Numerous racemose branches borne along a central axis; the axis straight, unilateral, 8-30 cm long; branches 1-19 cm long, ascending to reflexed, with 2 rows of spikelets; spikelets 2-4 mm with 2-5 florets, green, magenta, or maroon; glumes sometimes exceeding florets, linear to narrowly elliptic, acute, attenuate, or aristate; lemmas 1-2 mm, glabrous or sericeous; paleas glabrous or sericeous; caryopsis ellipsoid, 0.5 mm long, dark brown. Ecology: Found in moist habitats of wetlands, swamps, and open lowland soils; also an agricultural weed; from 1,000-5,000 ft (305-1524 m); flowers May-September. Distribution: Cosmopolitan; In much of the southern half of the US from s CA east to MD; south through the Caribbean, MEX, to South America; naturalized in Africa and Australia. Notes: An erect annual grass, the sheathes and blades have sparse to dense long hairs with enlarged (papillose) bases; an inflorescence composed of a single axis with many ascending to spreading narrow branches, each branch with 2 rows of appressed multi-flowered spikelets. Subspecies mucronata is told apart by its linear to narrowly lanceolate glumes which are longer than the florets and caryopses without a ventral groove. Subspecies brachiata has shorter glumes and caryopses with a ventral groove. This species is distinguished from Leptochloa fusca (Dinebra fusca), another Sonoran Desert annual, by its small spikelets, 2-4 mm long (5-12 mm in L. fusca) and often reddish panicle. Leptochloa viscida (Dinebra viscida) is another annual with reddish spikelets, but that species has a small, dense panicle, 3-8 cm long. Ethnobotany: Unknown Etymology: Leptochloa is from Greek leptos, slender and chloe or chloa, grass, while panicea is of uncertain orgins. Synonyms: Leptochloa attenuata, Dinebra panicea, Leptochloa filiformis, many others, see Tropicos Editor: SBuckley 2010, FSCoburn 2014, AHazelton 2015