Zigadenus Michaux, Fl. Bor.-Am. 1: 213. pl. 22. 1803.
(Including Amianthium A. Gray)
Death Camas or death camass, star-lily, zygadene
Perennial herbs, with raphides, various Veratrum-alkaloids, saponins, tannins, and chelidonic acid; with tunicate bulbs (coat membranaceous or fibrous) or rarely rhizomes (in Z. glaberrimus). Roots contractile; vessels (with scalariform perforation plates) restricted to roots. Stem single, erect, glabrous. Leaves mostly basal and progressively reduced upwards on stem (plants often appearing scapose), spirally arranged, simple, linear to linear-lanceolate, lorate, often keeled and sometimes conduplicate, occasionally falcate, lower leaves at least somewhat sheathing at base, obtuse to acute at apex, entire, usually glabrous but somewhat scabrous along margins and keel; venation parallel with midrib; stomata anomocytic, on both sides of leaf or sometimes rare on adaxial surface. Inflorescence racemose, corymbose, to branched and paniculate, polytelic, terminal. Flowers 3-merous, actinomorphic, perfect or occasionally terminal flowers on inflorescence branches staminate (plants then andromonoecious), perigynous, hypogynous to partly epigynous, pedicellate, ascending, spreading, or nodding, bracteate, protandrous. Tepals 6, distinct, biseriate, usually subequal with outer whorl usually ± shorter than the inner, narrowly lanceolate to ovate or sagittate, acute to obtuse at apex, gradually narrowed at base to sometimes distinctly clawed, glabrous or papillate adaxially, entire, ascending to spreading (often becoming erect in fruit), petaloid, white or cream-colored (then sometimes becoming green or pink to purplish with age), yellow, greenish yellow, green, yellow with white margins, or white streaked with green, sometimes tinged with brown, pink, or purple, usually bearing 1 (connate) to 2 (± distinct) variously shaped, yellowish or brownish basal nectariferous gland(s) (absent in Z. muscitoxicus; absent to obscure and/or disappearing in dried specimens in Z. densus), imbricate or valvate, persistent. Stamens 6 in 2 whorls; filaments distinct, basally expanded; anthers basifixed or sometimes dorsifixed, confluently 1 locular, reniform to cordate, with valvate dehiscence (opening into a peltate disc), extrorse or rarely introrse (Z. glaberrimus); pollen grains ellipsoid, 1 sulcate, sculpturing reticulate. Gynoecium 3 carpellate, ± syncarpous (carpels commonly appressed) to partly apocarpous; ovary ± superior to half-inferior, 3 locular, 3 lobed, placentation axile to parietal; ovules 2 to numerous per carpel, anatropous or campylotropous, bitegmic; the megagametophyte of the Polygonum type; styles 3, distinct, spreading to recurved, persistent; stigmas 3, obscure, terminal. Fruit a septicidal (ventricidal) capsule. Seeds few to numerous, fusiform to oblong, angled, brown or occasionally with reddish or purplish, somewhat fleshy testa (Z. muscitoxicus); endosperm development helobial; embryo small; endosperm copious.
Base chromosome numbers 8, 11, 26(?). (Including Amianthium A. Gray, Amiantanthus Kunth, Anticlea Kunth, Chitonia Salisb., Chrosperma Raf., Cyanotris Raf., Gomphostylis Raf., Monadenus Salisb., Oceanoros Small, Toxicoscordion Rydb., Tracyanthus Small). Type species: Zigadenus glaberrimus Michx.; the only species in the protologue. (Name from Greek zygos, yoke, and aden, gland, referring to the basal tepal glands occurring in most species.)