Herbs, perennial, from bulbs. Bulbs solitary or clustered, tunicate, ovoid to globose; tunic black or brown. Leaves basal, appearing whorled; blade linear, keeled. Inflorescences appearing terminal, racemose, bracteate; bracts sterile or subtending flowers, narrowly lanceolate. Flowers actinomorphic or zygomorphic; tepals 6, persistent, ± equal in 2 whorls of 3, distinct, violet, blue, or white, each 3–9-veined, lanceolate, ± twisted in drying; stamens 6; filaments inserted on receptacles at base of tepals, slender; anthers versatile, dehiscence introrse; ovary 3-locular, septal nectaries present, ovules 6–36; style filiform; stigma 3-lobed; pedicel spreading to incurving-erect in fruit. Fruits capsular, ovoid to ellipsoid or subglobose, dehiscence loculicidal. Seeds 6–36, lustrous black, obpyriform to ovoid-ellipsoid, 2–4 mm. x = 15.
Species 6 (6 in the flora).
Cmassia has been associated with other western North American genera of Liliaceae such as Schoenolirion, Hastingsia, and especially Chlorogalum (F. Speta 1998; M. Pfosser and F. Speta 1999), but recent molecular evidence (D. J. Bogler and B. B. Simpson 1996; M. F. Fay and M. W. Chase 1996) suggests that it may be related instead to the Agavaceae. Furthermore, the bimodal, 2n = 30 karyology of Camassia (A. Fernandez and J. R. Davina 1991) is similar to that of Agavaceae (D. Satô 1935) and not that of Chlorogalum.
Camassia bulbs have been an important food staple for native Americans, especially in the Pacific Northwest (G. R. Downing and L. S. Furniss 1968; N. J. Turner and H. V. Kuhnlein 1983), where bulbs were dug and traded on large encampment meadows. Similarity to the poisonous bulbs of Zigadenus (“death camas”) is a concern where ranges of the two genera overlap. Several Camassia species are cultivated and represent a major horticultural contribution from the native flora.
Variation and intergradation of C. angusta and C. scilloides have been reviewed by T. A. Ranker and A. F. Schnabel (1986), as well as J. A. Steyermark (1961), R. O. Erickson (1941), and F. W. Gould (1942).
|1||Tepals connivent over capsules after anthesis and deciduous as capsules develop, or withering separately.||> 2|
|1||Tepals mostly withering separately at base of capsules after anthesis, sometimes connivent over capsules, not deciduous.||> 4|
|2||Fruiting pedicels usually incurving-erect (often with capsules closely appressed to raceme axes); flowers actinomorphic or zygomorphic [5 tepals curving upward, the 6th downward; usually (4–)10–35(–58) blooming simultaneously, except on few-flowered individuals]; tepals long-persistent on fruiting racemes.||Camassia quamash|
|2||Fruiting pedicels usually spreading-erect (capsules not appressed to raceme axes); flowers actinomorphic (usually 1–3 blooming simultaneously); tepals connivent over capsules after anthesis, deciduous as capsules develop.||> 3|
|3||Capsules dull green, ovoid to ellipsoid, 10–25 mm; seeds 6–12 per locule; s British Columbia to c California.||Camassia leichtlinii|
|3||Capsules shiny green, subglobose, 5–10 mm; seeds 2–5 per locule; sw Oregon.||Camassia howellii|
|4||Capsules subglobose or ovoid-ellipsoid; e Great Plains to Appalachians and Great Lakes to s United States.||> 5|
|4||Capsules ovoid or ellipsoid; s British Columbia, s Alberta, nw United States.||> 6|
|5||Inflorescences 19–47 cm, with 0–5 sterile bracts; fruiting pedicels mostly spreading-erect; capsules subglobose; flowering earlier than sympatric populations of Camassia angusta.||Camassia scilloides|
|5||Inflorescences 27–87 cm, with 3–28 sterile bracts; fruiting pedicels mostly incurving-erect; capsules ovoid-ellipsoid; flowering later than sympatric populations of Camassia scilloides.||Camassia angusta|
|6||Bulbs usually clustered, ellipsoid, 2–7 cm diam.; leaves rarely fewer than 10, 2–5 cm wide; ne Oregon and adjacent Idaho.||Camassia cusickii|
|6||Bulbs seldom clustered, globose, 1–5 cm diam.; leaves usually fewer than 10, 4–20 mm wide; widespread in Pacific Northwest.||Camassia quamash|