Vicia L.
(Hermann, 1960; Gunn, 1979)
Plants annual,
biennial, or perennial herbs, with taproots or rhizomes. Stems erect to more
commonly spreading or climbing, sometimes mat-forming, angled or ridged but not
winged, unbranched or more commonly branched,
unarmed, glabrous or pubescent with nonglandular
hairs. Leaves alternate, even-pinnately compound with
2 to numerous leaflets, the petiole short or absent, unwinged,
the rachis extended into a conspicuous, unbranched or
branched tendril (this absent or poorly developed and bristlelike
elsewhere). Stipules more or less leaflike, in some
species with a basal outgrowth or lobe of tissue on 1 side, this rounded or
more commonly triangular, descending or clasping the stem, the margins
otherwise entire or toothed, the venation mostly inconspicuous, persistent; stipels absent. Leaflets variously shaped (sometimes even
on the same plant), the margins entire, the surfaces glabrous or hairy, pinnately veined or only the midvein
visible. Inflorescences axillary, spikelike racemes
or clusters, sometimes reduced to solitary flowers, the bracts 1–3 mm long,
shed early, bractlets absent. Calyces 5-lobed, the
tube cylindric to bell-shaped, often at least
slightly oblique, sometimes somewhat pouched on 1 side at the base, more or
less 2-lipped, the lobes subequal or the 3 lower
lobes longer than the upper 2, variously shaped, sharply pointed at their tips,
glabrous or hairy. Corollas papilionaceous, blue,
purple, red, yellow, or white, sometimes with darker nerves or appearing bicolorous), lacking conspicuous, contrasting markings near
the base of the banner, the banner with a short, broad, stalklike
base overlapping the wings, the expanded portion obovate
to nearly circular, slightly to deeply notched at the tip, curved or bent
upward or backward, the wings oblong to obovate,
shorter than to slightly longer than the banner, usually curved over or around
and fused to the keel below the midpoint, the keel shorter than the wings,
boat-shaped, slightly to strongly curved upward, rounded or tapered to a
bluntly or sharply pointed tip. Stamens 10, 9 of the filaments fused and 1 free
nearly to the base, all similar in length, the free portions of the filaments
slender, not broadened toward their tips the anthers small, attached at the
base, all similar in size, yellow or occasionally orange. Ovary sessile or
short-stalked, glabrous, the style abruptly curved or bent upward toward the
base, not flattened, usually hairy toward the tip, the hairs encircling the
style or in a tuft on the outer side, more or less persistent at fruiting, the
stigma terminal, short. Fruits legumes, mostly oblong
to elliptic, tapered asymmetrically to a sharply pointed or more commonly
beaked tip (rounded elsewhere), flattened, slightly constricted between the
seeds or not, straight or slightly curved upward, 2- to numerous-seeded,
dehiscing by 2 valves, these green to brown at maturity, usually twisting
spirally after dehiscence. Seeds oblong to oblong-elliptic, broadly ovate, or
circular in outline, flattened or not, the surface smooth, reddish brown to
dark brown, sometimes mottled, often dull. About 160 species, North America to
South America, Europe, Asia, Africa, Pacific Islands, most diverse in temperate
regions.
Vicia is a member of the tribe Fabeae, which is one of the most economically important
groups in the family and also includes the related genera Lathyrus L. (sweet pea, vetchling), Lens
Mill. (lentil), and Pisum L. (garden pea). Vicia is very
similar to Lathyrus,
but differs in having unwinged stems, generally
smaller leaflets and flowers, filament tubes ending obliquely, and unflattened styles with hairs usually encircling the tip.
Preliminary findings from molecular phylogenetic
studies by Wojciechowski et al. (2004) suggest that,
as currently circumscribed, the genus Vicia may not be natural, comprising two or more groups,
some of which may be more closely related to other genera in the tribe than to
the rest of Vicia.
Determinations of taxa within Vicia can be a bit confusing, requiring multiple characters
to separate species (Gunn, 1968, 1979; Isely, 1998).
Leaf characters are generally relatively similar, with only minor variation in
leaflet number, size, pubescence, and tendril branching. Self-pollinating
species are particularly variable in plant size, number of leaflets,
pubescence, flower color, and seed size and color. Seed characters are
sometimes useful, but are overlapping (Lassetter,
1978). Some Old World species that were introduced long ago for cover crops
have been collected a few times as escapes in Missouri, and might still persist
in waste areas.
Vicia is widely cultivated as a cover crop
and green manure for soil improvement and erosion control. The leaves of all
species are palatable and nourishing to livestock, with few toxicity problems.
However, the seeds of V. sativa and V. villosa are
associated with neurotoxicity and skin problems when eaten by livestock
(Burrows and Tyrl, 2001). Seeds of V. faba L.
(fava bean, broad bean) are commonly eaten by people in Europe, the Mediterranean
region, and China; however, unless cooked thoroughly they cause a kind of haemolytic anemia known as favism,
particularly among a genetically predisposed segment of the population (Sokolov, 1984).