5. Corispermum L. (bugseed)
Plants annual,
the taproot not tuberous-thickened, the aboveground portions sparsely to
densely pubescent with small, stellate hairs, sometimes becoming nearly
glabrous at maturity. Stems erect or ascending, rarely spreading, not
succulent, not appearing jointed, few- to much-branched. Leaves alternate, well
developed, not succulent, sessile or nearly so. Leaf blades linear to narrowly
lanceolate, flattened in cross-section, not clasping the stem, narrowed to a
sharply pointed tip, narrowed at the base, the margins entire. Inflorescences
terminal on the branches, slender to somewhat club-shaped spikes, the flowers
solitary, not sunken into the axis. Flowers all or nearly all perfect (a few pistillate
flowers occasionally present). Bract 1 per flower, somewhat leaflike, cupping
the fruit, lanceolate to ovate, tapered to a sharply pointed tip. Calyx of 1
sepal (absent or 3 elsewhere), this tiny (0.5–1.0 mm long), scalelike,
irregularly oblong-ovate, rounded at the tip, persistent at fruiting, not
concealing the fruit, rounded on the back, not winged. Stamens 1–3(–5). Ovary
superior. Style absent or 1 and very short, the stigmas 2, linear. Fruits
unequally elliptic in cross-section (the inner surface flattened to slightly
concave), elliptic to obovate or nearly circular in outline, flattened
vertically, indehiscent, the wall papery to somewhat leathery or hardened,
usually with reddish brown spots and occasionally a few small, whitish, warty outgrowths.
Seed adhering more or less tightly to the fruit wall, positioned vertically,
1.5–4.0 mm long, elliptic to oval in outline, flattened, the surface smooth,
dark brown to nearly black, shiny, the embryo appearing more or less
ring-shaped. About 60 species, North America, Europe, Asia.
Species of Corispermum
are very difficult to distinguish, especially if mature fruits are not present.
Perhaps because of this, the taxonomy of the genus in North America is
controversial. Some authors (Maihle and Blackwell, 1978; Brooks, 1986) have
contended that the three or four species present in North American are
introduced from the Old World. However, Mosyakin (1995) accepted eleven species
as occurring in the region, with at least eight of these said to be native.
Paleobotanical evidence (Betancourt et al., 1984) documents the presence of one
or more members of the genus in western North America (at least some of these
similar in fruit morphology to modern C. villosum) over a period between
more than 38,000 and less than 1,500 years ago, so perhaps the modern materials
should correctly be considered all or in part indigenous to the New World.
However, Mosyakin’s (1995) narrow taxonomic circumscriptions (which he states
to be preliminary pending more detailed research) have been challenged by some
recent authors (Judd and Ferguson, 1999). The bulk of the morphological
variation that has given rise to this controversy occurs in plants to the west
and/or north of Missouri. Because Mosyakin (1995 and pers. comm.) accepted the
same number of taxa for Missouri as did earlier authors (Steyermark, 1963;
Maihle and Blackwell, 1978), the present treatment tentatively accepts his
newer nomenclature.
In regions to
the west of Missouri where Corispermum is more abundant, the genus is
considered a good forage for livestock.