Schoenocaulon

Herbs, perennial, scapose, from tunicate bulb-rhizomes. Leaves narrow, grasslike, emerging conduplicate from neck of fibrous tunic. Inflorescences racemose, simple; racemes spikelike, flowers subtended by a persistent, membranous bract; distalmost bracts empty or concealing rudimentary flowers. Flowers: proximalmost bisexual, distalmost functionally staminate; tepals withering-persistent, 6, distinct, equal, leathery to slightly petaloid, yellowish green, green, or greenish purple, not clawed, linear-lanceolate to ovate, margins entire to crenulate or minutely denticulate; hyaline basal auricle sometimes present; perigonal nectaries not well developed; stamens 6, distinct; filaments withering-persistent, subulate or rarely distally dilated, 1.5–2.5 times tepal length; anthers basifixed, narrowly sagittate before dehiscence, explanate after, extrose; ovary superior, 3-locular, locules barely cohesive to connate; styles persistent, 3, distinct. Fruits capsular, 1–3-locular, dehiscence septicidal. Seeds 1–8 per locule, ellipsoid to ovoid or conic, irregularly compressed or angled by mutual pressure. x = 8.

Distribution

Western Hemisphere, especially Mexico.

Discussion

Species 24 (3 in the flora).

Schoenocaulon has rarely been collected in the United States in recent times; all three species are possibly threatened. The genus is a source of cerveratrum alkaloids.

Selected References

Brinker, R. 1942. Monograph of Schoenocaulon. Ann. Missouri Bot. Gard. 29: 287–309.

Frame, D. 1989. Schoenocaulon. In: R. McVaugh and W. R. Anderson. 1974+. Flora Novo-Galiciana: A Descriptive Account of the Vascular Plants of Western Mexico. 8+ volumes. Ann Arbor. Vol. 15, pp. 263–275.

Frame, D., A. Espejo, and A. R. López-Ferrari. 1999. A conspectus of Mexican Melanthiaceae including a description of new taxa of Schoenocaulon and Zigadenus. Acta. Bot. Mex. 48: 27–50.

Frame, D. 2001. Chromosome studies in Schoenocaulon (Liliaceae: Melanthieae) a relict genus. Anales Inst. Biol. Univ. Nac. Auton. Mexico, Bot. 72: 123–129.

Lower Taxa

Schoenocaulon dubium, Schoenocaulon ghiesbreghtii, Schoenocaulon texanum

Key

1	Racemes loose, flowers well separated along axis; Florida.	Schoenocaulon dubium
1	Racemes condensed, flowers closely packed along axis; New Mexico, Texas.	> 2
2	Tepal margins crenulate to minutely denticulate.	Schoenocaulon ghiesbreghtii
2	Tepal margins entire.	Schoenocaulon texanum