3. Acalypha monococca (Engelm. ex A. Gray) Lill. W. Mill. & Ghandi (one-seeded mercury)

A. gracilens var. monococca Engelm. ex A. Gray

A. gracilens A. Gray ssp. monococca (Engelm. ex A. Gray) G.L. Webster

Map 1651, Pl. 376 g

Stems 10–45 cm long, sparsely to densely pubescent with short, strongly curved hairs. Leaves short-petiolate, the petiole 1/16–1/4 as long as the blade, shorter than to occasionally about as long as the inflorescence bracts. Leaf blades 1–7 cm long, linear to lanceolate, angled or somewhat tapered at the base, angled or tapered to a usually sharply pointed tip, the margins entire or with relatively few (mostly 3–5 on each side) broadly spaced, blunt, minute teeth, sometimes appearing minutely scalloped, relatively thin-textured to somewhat thicker and stiffer, the surfaces sparsely to moderately pubescent with short, straight to curved, loosely appressed hairs. Inflorescences entirely axillary spikes, 1–3 per node, each with 1(–3) basal pistillate node(s) (each with a separate folded bract) below few to several nodes of staminate flower clusters, the tip of the spike usually extending well beyond the bracts. Inflorescence bracts 1 per pistillate node, 4–16 mm long, appearing more or less folded longitudinally around the inflorescence, with (9–)10–17 mostly lanceolate to triangular-ovate lobes, the margins sparsely to moderately bristly-hairy, at least some of the hairs usually gland-tipped, the outer surface sparsely to densely hairy, usually at least some of the hairs gland-tipped, also with sparse to moderate minute, reddish, sessile glands. Fruits 1.8–2.6 mm long, 1-locular, 1-seeded, the surface moderately hairy and occasionally also with sparse, minute, sessile glands, lacking tubercles or slender projections at maturity. Seeds 1.6–2.4 mm long. 2n=40. May–October.

Scattered nearly throughout Missouri but uncommon or absent from most of the northwestern quarter of the state (Illinois to Iowa and Kansas south to Kentucky, Arkansas, and Texas). Glades, upland prairies, sand prairies, ledges and tops of bluffs, savannas, and openings of mesic to dry upland forest; also pastures, railroads, and roadsides.

For a discussion of the taxonomic problems involving this species and A. gracilens, see the treatment of that species.