CHICKWEED FAMILY 271 



17. A. calycantha (Bong.) Rj-db. Stems numerous, decumbent, more or 

 less pubescent; leaves ovate-lanceolate, ciliolate at least at the base, 5-15 mm. 

 long; sepals lanceolate, acute, about equalling the rounded-ovoid or subspheric, 

 obtuse capsule. S. calycantha Bong. Wet places in the mountains: Mont.— 

 Colo. — Calif. — -Alaska. Mont. — -^4/^. Jl-S. 



18. A. washingtoniana (B. L. Robins.) Heller. DeUcate annual (?); stems 

 decumbent, quite simple, more or less pubescent; leaf -blades ovate, acute, short- 

 petioled, thin, 8-10 mm. long, finelj' cHiate near the base; peduncles spreading; 

 sepals four, ovate, acute, 2-3 mm. long, slightly scarious-margined; petals none; 

 capsule ovoid. S.washingtoniana B.h.Jiohins. Woods and dr}' ground : Wash. 

 — Ida. SubmoTit. — Mont. Jl-Au. 



19. A. Palmeri Rydb. Stems spreading, 5 cm. high or less, glabrous; leaves 

 ovate or ovate-lanceolate, 2-5 mm. long, fleshy, acute; cjTiie 3-5-flowered ; 

 sepals lanceolate, 2.5-3 mm. long, acute; petals about equalling the sepals. 

 Valleys: s Utah. Son. 



20. A. polygonoides Greene. Stem diffuse, 3-10 cm. long; leaves thick, 

 ovate, 6-12 mm. long; cjones several-flowered, with short branches and pedicels; 

 sepals narrowly lanceolate, slightly scarious-margined, 4 mm. long, acute, nearly 

 twice as long as the petals. High mountains: Colo.- — ^Utah. Subalp. Jl-Au. 



21. A. Curtisii Rydb. Stem sharply 4-angled, erect, branched, 2-6 dm. 

 high, glabrous, except in the inflorescence; leaves rounded and half clasping at 

 the base, 3-6 cm. long; sepals about 3 mm. long, thick, ovate-oblong, obtuse or 

 acutish, with a narrow white margin; petals about 7 mm. long. Open woods: 

 Wyo. — Colo. — Ariz. — Xev. Subtnont. — Mont. Je-Au. 



22. A. Jamesiana (Torr.) Heller. Stem strongh' angled, 2-5 dm. high, 

 viscid above; leaves elongate-lanceolate, 5-12 cm. long, broadest near the base; 

 inflorescence leaf}'; sepals oblong or elliptic, thin, 4-5 mm. long; petals 7-8 

 mm. long. S. Jamesiana Torr. Moist woodlands: Wj'o. — -Tex. — Calif. — Ida. 

 Submont. — -Mont. My-Au. 



23. A. americana (Porter) Rydb. Stems branched, very leaf}^, 1-2 dm. 

 high, viscid-puberulent; leaves sessile, ovate, obtusish, 1-3 cm. long; cj-mes 

 very leafy; pedicels short; sepals ovate, obtuse, 3-4 mm. long; petals about 6 

 mm. long. S. dichotoma americana Porter. Rock slides: Mont. Subalp. Je- 

 Au. 



2. CERASTIUM L. Mouse-ear Chickweed. 



Annual or perennial herbs, with pubescent, often viscid fohage. Leaves 

 opposite. Flowers cj-mose. Sepals 5, rarely 4. Petals as many, white, 2-cleft. 

 Stamens usually 10. Ovarj' one-celled; stjdes as many as the sepals and opposite 

 them, rarely fewer. Capsule cylindric, often curved, opening by 10, rarely 

 8, tooth-like valves. 



Annuals: pod 2-3 times as long as the calyx. 



Pedicels in fniit 1-3 times as long as the caly.x, straight or nearly so. 



1. C. brachypodum. 

 Pedicels in fruit 5 times as long as the calyx or longer; strongly curved above. 



2. C. nutans. 

 Perennials or rarely annuals; pods 1-2 times as long as the calyx. 



Leaves oblong, oval, or ovate, mostly obtuse, or barely acutish. 

 Petals 1 cm. long or more, fully twice as long as the sepals. 



Sepals, at least the outer ones, oval, obtuse, scarious-margined at the tip as 



well as on the sides. 3. P. pulchellum. 



Sepals lanceolate, acute, scarious mostly on the margins only. 

 Leaves and stem distinctly, although not copiously -s-lllous. 



4. C. alpinum. 

 Leaves and stem finely pilose. 5. C. Earlei. 



Petals less than 1 cm. long. 



Petals much exceeding the sepals. 



Leaves thick with a prominent midrib. 



Plant tall, 4-.5 dm. high; leaves linear-oblong. 12. C. Leibergii. 



Plant low, depressed, less than 1 dm. high; leaves ovate-lanceolat«. 



18. C. thermale. 

 Leaves thin; midrib not prominent. 



Sepals tinged with purple; stem depressed, 1-3-flowered. 



6. C. Beeringianum. 



