Flower:

Slender, erect, branching cluster ½ to 2 inches long at the top of the stem, often at least partially enclosed by the uppermost leaf sheath, with smaller panicles in the leaf axils usually fully enclosed by their sheaths. Panicle branches are compound and appressed with several spikelets (flower clusters) per branch. Spikelets are slightly flattened, 3 to 6 mm (to ¼ inch) long, often purplish, overlapping along a branch but not tightly crowded, have a single floret, are lance-shaped in outline when immature and more spreading at maturity.

At the base of a spikelet is a pair of bracts (glumes), both thin, hairless, awnless, 1-veined with minute teeth towards the tip end, lance to egg-shaped with a pointed tip, shorter than the spikelet, the lower glume 1.8 to 4.7 mm long, the upper glume about the same or slightly longer but still shorter than the spikelet. Florets are surrounded by a pair of bracts (lemma and palea), both lance-shaped to narrowly triangular and covered in long white hairs; the lemma tapering to a pointed tip, 1-veined and 3 to 5.4 mm long; the palea 2-veined, 2.1 to 6 mm long, often longer than the lemma, the tip extended to an awn-like beak up to 1 mm long.

Leaves and stems:

Leaves are mostly alternate, 1 to 2 mm wide at the base with long taper to thread-like tip, usually rolled in along the edges (involute), the upper surface rough, the lower surface smooth, sometimes with a few long spreading hairs near the base along the edges. Lower leaves are up to 4½ inches long, mid and upper stem leaf blades are shorter, usually shorter than the associated sheath. Sheaths are hairless except for a few long, spreading hairs at the tip. The ligule (membrane where the leaf joins the sheath) is a fringe of very short hairs. Nodes are smooth. Stems are single or multiple from the base, slender, smooth or rough but hairless, erect to ascending or prostrate from the base and rising near the tip (decumbent) or rising from a lower node (geniculate). Plants form loose to dense clumps.

Fruit:

Spikelets turn yellowish or mottled purple/gray at maturity, the mature florets dropping off individually leaving the glumes behind on the stalk. Grains (seeds) are brown to gray, flattened, irregularly oblong-elliptic, 2 to 3 mm long, 3 to 4 times as long as wide, with a large dark brown germ on one side.

Notes:

Poverty Dropseed is a small annual grass that has been collected scattered across Minnesota's praire region. Extremely drought tolerant, it is typically found in sparsely vegetated sand or gravelly soils and rock outcrops. In looking for it, we also discovered it frequently showing up in the gravelly road shoulders along asphalt roadways and urban waste areas. Small and easily overlooked, it is probably distributed more widely than herbarium records indicate.

Without spikelets, it is difficult to distinguish from the related Small Dropseed (Sporobolus neglectus); in fact S. neglectus was once consider a variety of S. vaginiflorus (var. neglectus). Both are small-statured annuals with panicles mostly enclosed in their sheaths, may have sparse hairs at the tip of the sheath and/or leaf edges, and are found in the same kinds of habitats. S. vaginiflorus is a somewhat larger plant (to 16 inches tall vs. 12 inches) with longer spikelets (3 to 6 mm vs. 1.5 to 3 mm), longer grains, and the lemmas and paleas are distinctly hairy where S. neglectus is hairless.

There are 2 recognized varieties of S. vaginiflorus: var. ozarkanus, a more southern species most common in Missouri, has sheaths sparsely hairy at the base, glumes usually longer than the florets and 3-veined lemmas; var. vaginiflorus, common in the eastern half of North America, has hairless sheath bases, glumes usually shorter than the florets and 1-veined lemmas.