Veratrum Linnaeus, Sp. Pl. 2: 1044. 1753; Gen. Pl. 1013. 1754.
(Including Melanthium L.)
Perennial herbs with raphides, various Veratrum-alkaloids, phenolic substances (resveratrol), flavonoids (luteolin), saponins, and chelidonic acid. Rhizomes thick and elongate to very reduced, terminating in a fibrous, tunicate bulb. Roots fleshy, contractile, adventitious; vessels (with scalariform perforation plates) restricted to roots. Stem single, erect, pubescent (at least on inflorescence axis and then floccose), with some secondary growth (V. viride). Leaves mostly basal and progressively or abruptly reduced upwards on stem (plants sometimes appearing ± scapose), alternate, spiral, simple, linear, linear-lanceolate, oblanceolate, broadly ovate, elliptic to broadly elliptic, obovate, sessile to distinctly petiolate, with closed tubular sheath (these sometimes overlapping, forming a hollow pseudostem), with obtuse to long-attenuate apex, entire, sometimes longitudinally plicate, pubescent or glabrous; venation parallel, consisting of several prominent primary veins (in plicate leaves) or a midrib and less conspicuous primary veins (in non-plicate leaves); stomata anomocytic, on abaxial surface and absent/rare on adaxial surface. Inflorescence a compound raceme or panicle, pubescent (hairs floccose), polytelic, terminal. Flowers 3-merous, actinomorphic, perfect and often imperfect (those on lowermost inflorescence branches mostly staminate, and plants then andromonoecious), perigynous, hypogynous to semi-epigynous, pedicellate, erect to spreading, bracteate, protandrous, frequently progressively smaller distally on the inflorescence. Tepals 6, distinct to slightly connate basally, free to adnate to ovary base, often smaller in staminate flowers, biseriate, often subequal (then outer whorl broader, shorter and more pubescent than the inner), lanceolate to broadly elliptic, oblong-obovate to rhombic, obtuse to acute at apex, gradually to abruptly narrowed at base into a claw (then blade auriculate or hastate), plane or sometimes strongly undulate or crisped, with entire or erose to denticulate [deeply fimbriate] margins, erect to reflexed, glabrous or abaxially pubescent and then often adaxially papillose, petaloid, white to greenish white (then sometimes becoming green or maroon with age), yellow-green, yellow, green, brownish to maroon (or tinged with brownish or maroon), maroon adaxially and green abaxially, yellow, or white with green base, nectariferous at base with 2 distinct succulent glands or a variously shaped, marginal or intramarginal, thickened glandular area (then very reduced, and appearing as faint spots just below mid-tepal in V. parviflorum), persistent. Stamens typically 6 in 2 whorls, erect, spreading, or incurved, persistent; filaments distinct, ± free to variously epitepalous, filiform or sometimes basally expanded; fugaceous or persistent; anthers basifixed, confluently 1 locular, reniform to cordate becoming peltate after dehiscence, with valvate/apical dehiscence (opening into a peltate disc), extrorse; pollen grains ellipsoid, 1 sulcate, sculpturing reticulate. Gynoecium 3 carpellate, weakly syncarpous (carpels incompletely fused, weakly appressed, or coherent); ovary superior to partly (one-third) inferior, 3 locular, deeply lobed, apex acute or truncate, walls moderately thick and opaque or thin and translucent, placentation axile to parietal; ovules few to numerous, anatropous or campylotropous, bitegmic; the megagametophyte of the Polygonum type and sometimes also of the Allium type in different ovules in the same ovary; styles 3, distinct, erect to divergent, sometimes slightly gynobasic, blunt and stigmatic adaxially at apex (i.e., stigmas indistinct), persistent; rudimentary ovary present in staminate flowers. Fruit a septicidal (ventricidal) capsule subtended by persistent perianth. Seeds ellipsoid-fusiform or clavate, compressed, brownish to yellowish, bright yellow, or green, broadly winged or wings reduced to basal ridges; endosperm development helobial; embryo small; endosperm copious.
Base chromosome number 8. (Including Acelidanthus Bentham & Hooker, Evonyxis Raf., Leimanthium Willd., Melanthium L.). Lectotype species: Veratrum album L.; see Britton & Brown, Illustr. Flora No. U.S. & Canada, ed. 2. 3: 94. 1913. (Name Latin for hellebore, either Helleborus L. [Ranunculaceae] or perhaps Veratrum album.)