RUSH FAMILY 157 



(rarely more) heads; the lower on slender curved peduncles; heads small, 3-5 

 mm. thick; sepals and petals elongated-lanceolate, about 2.5 mm. long, dark 

 brown; capsule 3-gonous, globose, mucronate, shorter than the perianth. Arc- 

 tic-alpine regions: Greenl. Canadian Rockies B.C. Alaska; Eurasia. Alp 

 Jl-Au. 



Family 20. ALLIACEAE. ONION FAMILY. 



Perennial scapose herbs, with bulbs or corms and narrow basal leaves. 

 Flowers in terminal umbels subtended by or enveloped in a scarious in- 

 volucre. Sepals and petals each 3, very similar, corolla-like, usually mem- 

 branous. Stamens 6. Pistil of 3 united carpels; ovary superior, 3-celled; 

 styles united. Fruit a loculicidal, 3-celled capsule. 



Perianth-segments distinct or nearly so; style articulate to the 3-lobed capsule ; bracts 



broad, spathaceous. 1. ALLIUM. 



Perianth-segments united into a tube, with adnate filaments; style not articulate to the 



capsule; bracts not spathaceous, distinct. 



Filaments not united into a tube; pedicels articulate; capsule ovate or oblong. 

 Filaments apparently in one series. 



Filaments opposite to the petals wing-appendaged at the base; anthers basi- 



fixed; flowers subcapitate. 2. DIPTEROSTEMON. 



Filaments all deltoid; anthers versatile; flowers umbellate. 



3. HESPEROSCORDION. 

 Filaments hi two series; the inner adnate to the free part of the petals; anthers 



versatile. 4. TRITILEIA. 



Filaments united into a tube; pedicels not articulate; capsule triquetrous, subglobose. 



5. ANDROSTEPHIUM. 



1. ALLIUM (Tourn.) L. ONION, GARLIC, LEEK, CHIVES. 



Perennial bulbous plants, with a characteristic alliaceous smell. Bracts 

 scarious, more or less connate. Petals and sepals free or slightly united at the 

 base. Stamens adnate to the bases of the petals and sepals; anthers introrse. 

 Ovary sessile, 3-celled; style filiform, usually deciduous; stigmas minute; ovules 

 1-6 in each cell. 

 Bulb crowning a persistent rootstock; outer coat more or less fibrous. 



Leaves terete and hollow; umbels dense, subcapitate. 1. A. sibiricum. 



Leaves flat or channeled, not hollow. 



Umbels rarely nodding; petals and sepals long-acuminate ; capsule not crested. 

 Stamens and styles exserted. 2. A. validum. 



Stamens and styles included, half as long as the petals. 3. A. brevistylum.L-^' 

 Umbels nodding; petals and sepals obtuse or acute; capsule 6-crested; stamens 



and style exserted. 

 Leaves rounded-convex on the back, not keeled, lunate in cross-section. 



4. A. recurvatum t 



Leaves almost flat or keeled, somewhat broadly V-shaped in cross-section. 

 Umbels many-flowered; leaves 3-5 mm. wide. 5. A.cernuum. 



Umbels few-flowered; leaves less than 3 mm. wide. 6. A. neo-mexicanum. 

 Bulbs without a rootstock. 

 Outer bulb-coat fibrous. 



Umbels bulblet- bearing ; flowers few or sometimes none. 



Capsule with 6 rounded crests. 7. A. fibrosum. 



Capsule not crested. 



Petals and sepals ovate. 8. A. rubrum. 



Petals and sepals oblong-lanceolate. 9. A. canadense. 



Umbels not bulblet-bearing. 



Capsule not crested; involucre usually 3-leaved. 



Petals and sepals with a thick rounded keel. 10. A. aridum. 



Petals and sepals not thickened on the back. 11. A. Nuttallii. 



Capsule crested. 



Petals and sepals more than 1 cm. long; peduncles often 2 or 3; sheaths 

 loose; bracts 3. 12. A. macropetalum. 



Petals and sepals less than 1 cm. long; peduncles solitary; sheaths close. 

 Bracts broadly ovate, usually 2, in flowers not reflexed; flowers white 



or light rose; several layers of the bulb-coat fibrous. 

 Plant 1-3 dm. high; pedicels 8-12 mm. long; petals and sepals 



about 5 mm. long. 13. A. textile. 



Plant 2-6 dm. high; pedicels 12-25 mm. long; petals and sepals 



6-8 mm. long. 14. A. Geyen. 



Bracts lanceolate, usually 3, soon reflexed; only outer bulb-coat fibrous; 



flowers red-purple. 15. A. Pikeanum. 



Outer bulb-coat not fibrous, but often more or less reticulate. 

 Petals more or less serrulate or denticulate on the margins. 



Petals and sepals acuminate, the former serrulate near the apex. 



Petals and sepals long-acuminate, one-half longer than the stamens. 



16. A. acuminatum. 



