658 GENTIANACEAE 



Corolla without a crown; leaves not white-margined. 



9. Frasera. 



Corolla with a decurrent crown contiguous with the gland; leaves 

 white-margined. 10. Leucocraspedum. 



Each division of the corolla with a pair of oblong glands and a separate 

 crown below; capsule flattened contrary to the valves. 



11. Tessaranthium. 

 Corolla spurred. 12. Tetragonanthus. 



1. CENTAUREUM Hill. Centaury, 



Annual, biennial, or rarely perennial caulescent herbs. Leaves opposite, 

 entire, sessile or clasping. Flowers in terminal cj^mes, pedicelled. Calyx with 

 4 or 5 keeled lobes. Corolla salver-shaped, rose-colored, pink, white, or yellow; 

 lobes 4 or 5, convolute. Stamens 4 or 5, partially adnate to the corolla-tube; 

 filaments short; anthers at last twisted. Ovary 1-celled; placentae 2, sometimes 

 intruding. Capsule oblong or fusiform, 2-valved. Seeds many, reticulate. 

 [Erythraea Neck.] 



Corolla-lobes 4-6 mm. long, about half as long as the tube; annuals. 



CoroUa-lobes oblong, obtuse. 1. C. exaltaium. 



Corolla-lobes ovate or lanceolate, acute. 2. C. Nuttallii. 



Corolla-lobes 7-10 nun. long, about three-fourths as long as the tube; pereiuiials. 



3. C. arizonicum. 



1. C. exaltatum (Griseb.) M. F. Wight. Stem 1-3 dm. high, slender, gla- 

 brous, with erect or strongly ascending branches; leaves sessile, oblong to linear, 

 1.5-4 cm. long; corolla-tube yellow, 8-10 mm. long; lobes rose-colored, 4-5 mm. 

 long. Erythraea Douglasii A. Gray. E. exaltata (Griseb.) Coville. Wet meadows 

 and river bars: Wash. — Calif.— Utah — Neb. Plain — SubmonL My-Jl. 



2. C. Nuttallii (S. Wats.) Heller. Stem 1.5-4 dm. high, with strongly 

 ascending branches; leaves oblong, acute; corolla-tube yellowish, about 10 mm. 

 long; lobes 5-6 mm. long. Erythraea Nuttallii S. Wats. Valleys: Utah-^Nev. 

 — Ida. Submont. Jl-S. 



3. C. arizonicum (A. Gray) Heller. Stem angled, 2-4 dm. high; basal 

 leaves spatula te; stem-leaves oblong to linear, usually acute, 2-5 cm. long; 

 corolla-tube about 12 mm. long, yellow; lobes elliptic or oblong, acute, 9-12 mm. 

 long. Erythraea calycosa arizonica A. Gray, River bottoms: Ariz. — s Utah. 

 Son. Je~Au. 



2. EUSTOMA Salisb. 



Annual caulescent herbs, or perennials by means of rosettes. Leaves oppo- 

 site, sessile or clasping, glaucous. Flowers in terminal cymose panicles, or soli- 

 tary. Calyx with 4 or 5 narrow keeled lobes. Corolla deeply campanulate, 

 blue, purple, or white; lobes 5 or 6, convolute in bud, erose-denticulate. Sta- 

 mens 5 or 6, adnate to the corolla-tube; filaments filiform; anthers versatile. 

 Ovary 1-celled; stigmas 2. Seeds numerous, pitted. 



1. E. Russelianum (L.) Griseb. Annual, or perennial with rosettes, with 

 a taproot; stem 3-6 dm. high; leaves ovate to lanceolate or oblong, 3-ribbed, 

 2-4 cm. long; calyx 15-20 mm. long; lobes subulate; corolla deep purple, rarely 

 white, 3-4 cm. long; lobes obovate. E. Andrewsii A. Nels. Meadows: Neb. — 

 Tex. — N.M. — Colo. Plain — Submont. Je-Au. 



3. ANTHOP6gON Necker. Fringed Gentian. 



Annual, biennial, or perennial "caulescent herbs. Leaves opposite, entire, 

 sessile. Flowers sohtary at the end of the stem or its branches, perfect, 4-merous. 

 Calyx large; lobes keeled, the inner distinctly wider than the outer, scarious- or 

 hyaline-margined. Corolla showy, funnelform; lobes erose or fimbriate, without 

 plaits in the sinuses, convolute. Stamens with glands at the base of the fila- 

 ments. Ovary 1-celIed; ovules numerous. Capsule stipitate. 



Annuals or biennials; flowers on naked long peduncles terminating the branches, not 



bract eate. 

 CoroUa enclosed in the ventricose wing-angled calyx. 1. A. ventricosus. 



Corolla much longer than the merely angled calyx. 



Inner calj^c-lobes ovate, fully twice as broad as the outer linear-lanceolate ones; 



stem-leaves linear. 



