1. Acalypha deamii (Weath.) H.E. Ahles (two-seeded mercury, large-seeded
A. virginica L. var. deamii Weath.
A. rhomboidea Raf. var. deamii (Weath.) Weath.
Map 1649, Pl.
376 i, j
20–60 cm long, glabrous or moderately to densely pubescent (sometimes
in vertical lines) with short, strongly curved hairs. Leaves long-petiolate,
the petiole slightly shorter than to slightly longer than the blade, much longer
than the inflorescence bracts. Leaf blades 1–12 cm long, ovate to
broadly rhombic, mostly broadly angled at the base, tapered to a sharply
pointed tip, the margins with several (mostly 10–15 on each side)
relatively closely spaced, usually blunt teeth, relatively thin-textured, the
surfaces sparsely to moderately pubescent with relatively straight, more or
less appressed hairs. Inflorescences entirely axillary spikes, 1–3 per
node, each with 1–3 basal pistillate flowers below few to several nodes
of staminate flower clusters, the tip of the spike not or only slightly
extending beyond the bract. Inflorescence bracts 8–25 mm long,
appearing more or less folded longitudinally around the inflorescence, with
(5–)7–9 linear to lanceolate lobes, the margins sparsely to
moderately hairy, the outer surface glabrous or sparsely hairy, sometimes some
of the hairs gland-tipped, lacking minute, sessile, reddish glands. Fruits
2.5–3.4 mm long, 2-locular, 2-seeded, the surface moderately to densely
hairy, lacking tubercles or slender projections at maturity. Seeds
2.2–3.2 mm long. 2n=40. July–October.
sporadic (Iowa, Kansas, and Arkansas east to Pennsylvania and Tennessee). Edges
and openings of bottomland forests and banks of streams and rivers.
This taxon was
not treated by Steyermark (1963), who merely mentioned its existence (as A.
rhomboidea var. deamii) in adjacent states. Miller (1964) mapped the
species from three Missouri counties but provided no specimen citations to
document her finds. Turner and Yatskievych (1992) first cited specimens from St. Louis and Pulaski Counties. The species remains relatively poorly known and may be
overlooked in the field due to its vegetative similarity with A. rhomboidea
(Becus, 2003). At present it appears to be rare throughout its range.
Cooperrider (1984) suggested that there were problems in distinguishing A.
deamii from A. virginica and treated it as a variety of that
species. However, the consistently 2-seeded fruits with seeds more than 2 mm
long are diagnostic for the species (Levin, 1999a). Gleason and Cronquist
(1991) and some other authors have emphasized the abruptly drooping leaf blades
as a unique feature of A. deamii, but this appears to be under seasonal
or environmental influence (Becus, 2003). Plants observed during the present
research in Pike County had spreading leaves similar to those of A.
rhomboidea plants at nearby locations.