3. Froelichia Moench (cottonweed, snake-cotton)
Plants annual
(perennial herbs elsewhere), but with the taproot sometimes appearing somewhat
woody. Aerial stems erect or strongly ascending, somewhat angled, densely pubescent
with unbranched, usually woolly hairs, especially the nodes often appearing
cobwebby, the hairs becoming shorter near the tip, occasionally also somewhat
sticky. Leaves opposite, positioned mostly below the stem midpoint, sessile or
nearly so. Leaf blades 5–14 cm long, somewhat thickened or leathery, linear to
narrowly oblong-lanceolate or narrowly oblanceolate, narrowed or tapered at the
base, narrowed or tapered to a sharply or bluntly pointed tip, the margins
entire, the upper surface densely pubescent with silky or woolly hairs but
frequently becoming nearly glabrous at maturity, the undersurface densely
persistently pubescent with woolly hairs. Inflorescences terminal, narrow
panicles with pairs of dense spikes ascending from the nodes of the main axis,
these sometimes reduced to short, dense clusters and the inflorescence then
appearing as an interrupted spike, the lateral branches often terminating in
simple spikes. Bracts similar in texture but much shorter than the sepals,
broadly ovate, papery or scalelike, glabrous. Flowers perfect. Sepals 5, fused
most of their length into a persistent, conical to flask-shaped, papery tube,
this becoming somewhat hardened and developing winglike longitudinal ridges or
rows of spines and also basal tubercles after flowering, white to yellowish
white, densely pubescent with woolly hairs, the lobes 1–2 mm long, oblong to
lanceolate, bluntly to sharply pointed, greenish white, sometimes
pinkish-tinged, more or less glabrous. Stamens 5, the filaments fused nearly
their entire length, persistent, the anthers appearing sessile in the sinuses
between 5 short, strap-shaped lobes. Ovary ovoid. Ovule 1. Style well
developed, persistent, the stigma 1, capitate. Fruits shorter than and hidden
within the persistent calyx and anther tubes, with membranous walls, ovoid,
glabrous, indehiscent, 1-seeded. Seeds somewhat flattened, circular or nearly
so in outline, the surface shiny. Twelve to 20 species, U.S. and adjacent
Canada to South America, Caribbean Islands.
To observe the
crests and tubercles on the fruiting calyx, it is necessary to first remove the
thick woolly covering of hair.