1. Laportea canadensis (L.) Gaudich. (wood nettle)
Pl. 571 f, g;
Map 2671
Plants perennial
(but often flowering the first year), armed with sparse to dense, long,
stinging hairs, also with sparse to dense, shorter, finer, nonstinging hairs,
with rhizomes, the roots fibrous, sometimes somewhat tuberous. Stems 35–150 cm
long, erect or strongly ascending, usually unbranched, often slightly zigzag.
Leaves alternate, long-petiolate, stipulate. Leaf blades 6–20(–30) cm long,
ovate to broadly ovate, elliptic, or broadly elliptic, broadly angled to
rounded or shallowly cordate at the base, short-tapered at the tip, the margins
coarsely toothed, the venation pinnate or the 2 basalmost lateral veins slightly
more developed than the others; cystoliths rounded. Inflorescences axillary
(but sometimes also appearing terminal), small clusters arranged in panicles,
the staminate panicles usually shorter-stalked then the subtending petiole and
positioned at nodes below the pistillate ones, which usually are longer than
the subtending petiole. Bractlets absent. Staminate flowers with 5 sepals,
these 0.8–1.1 mm long, cupped around the stamens. Stamens 5. Pistillate flowers
with 4 free sepals, the calyx consisting of 2 smaller sepals, these 0.2–0.3 mm
long (occasionally totally absent), spreading, alternating with 2 larger
sepals, these 0.8–1.1 mm long, loosely cupped around but not fused to the ovary
and fruit. Style elongate (persistent at fruiting and sometimes hooked), the
stigmatic region linear. Fruits 2–3 mm long, obliquely attached at the tip of a
short, winged stalk, strongly flattened, the body more or less circular in
outline, greenish brown to dark brown, glabrous. 2n=26. May–August.
Scattered to
common throughout the state (eastern U.S. west to North Dakota and Oklahoma;
Canada). Bottomland forests, swamps, margins of sloughs and oxbows, and banks
of streams and rivers; also roadsides.
Steyermark
(1963) noted that this species is one of the greatest nuisances to those hiking
in bottomlands in Missouri, especially because it tends to occur in dense,
large stands. In deference to his adventures in the neotropics, he was quick to
point out that the burning sensation imparted by Laportea cannot compare
to the severity of the stinging hairs of some tropical genera.