CHICKWEED FA:MILY 269 



None of the bracts scarious. 



Leaves linear to lanceolate, more than four times as long as broad; plants 

 perennial, with running rootstocks. 

 Petals equalling or exceeding the sepals. 



Plant low. less than 1 dm. high, bluish green. 8. A. laeta. 

 Plant slender, light green, more than 1 dm. high. 



11. A. crassifolia. 

 Petals much shorter than the sepals, or none. 



Sepals with narrow scarious margins, acute; leaves oblong-lanceolate, 

 narrowed at the base; midrib not unusually strong: petals usually 

 lacking. 12. A. borealis. 



Sepals with broad scarious margins, acuminate : leaves linear-lanceolate, 

 with a strong midrib; petals usually present. 

 Leaves 2-8 mm. wide, broadest near the base. 



13. A. brachypetala. 

 Leaves 8-15 mm. wide, broadest near the middle. 



14. A. oxyphylla. 

 Leaves ovate-lanceolate, ovate or oval, less than four times as long as broad; 



cespitose perennials, except No. 18. 

 Leaves thin. 



Stem glabrous or nearly so. 



Sepals acute or acuminate. 15. A. crispa. 



Sepals obtuse. 16. A. obtusa. 



Stem distinctly pubescent. 



Leaves sessile; flowers more or less cymose. 17. A. calycantha. 

 Leaves short-petioled ; flowers solitary in the axils. 



18. A. washingtoniana. 

 Leaves thick. 



Petals equalling or exceeding the sepals; branches simple, ascending. 

 Leaves ovate, bluish green, with strong midrib; petals longer than 



the obtusish sepals. 9. A. Edwardsii. 



Leaves oval, bright green; midrib not strong; petals equalling the 

 acute sepals. 19. A. Palmeri. 



Petals shorter than the sepals; branches divaricately branched, spread- 

 ing. 20. A. polygonoides. 

 Plant more or less viscid, especially the upper portion; perennials with rootstocks. 

 Plant tall, 1-3 dm. laigh, erect; leaves linear to lanceolate. 



Leaves linear or Unear-lanceolate, 2-5 mm. wide. 21. A. Curtisii. 



Leaves lanceolate, 5-10 mm. wide. 22. A. Jamesiana. 



Plant low, diffuselj' cespitose; leaves ovate. 23. A. americana. 



1. A. media L. Stem diffusely branched, prostrate or ascending, 1-4 dm. 

 long, glabrous except the pubescent lines; leaf-blades 0.5-3.5 cm. long; sepals 

 oblong, glandular-pubescent, about equalling the capsule; petals shorter than the 

 sepals. *S. media Cvrill. Chickweed. Waste places, cultivated grounds, etc.: 

 Greenl.— Fla.— CaUf.— B.C.; W. Ind.; nat. from Eu. Ja-D. 



2. A. nitens (Nutt.) Greene. Stem branched near the base, glabrous or 

 somewhat pubescent below, erect, 1-2 dm. high; basal leaf -blades ovate, acute, 

 4r-5 mm. long; stem-leaves 6-10 mm. long; sepals lanceolate, acute, 3-4 mm. 

 long, 3-nerved at the base; petals about half as long as the sepals, or sometimes 

 wanting. S. nitens Nutt. <S'. praecox A. Nels. Wet places: w Mont. — Utah 

 —Calif.— B.C. Son.—Submont. Mr-Je. 



3. A. baicalensis Coville. Stem weak, ascending, or decumbent at the 

 base, 3-30 cm. high; leaves 6-20 mm. long; bracts lanceolate; sepals 2-2.5 mm. 

 long, glabrous, scarious-margined. S. nmheUata Turcz. Around springs and 

 brooks: Mont. — N.M. — Calif. — Ore.; Siberia. Submont. — Alp. Jl-Au. 



4. A. alpestris (Fries) Rydb. Stem 2-4 dm. high, angled; leaves sessile, 

 linear, 2-4 cm. long, 2-4 mm. wide; bracts lanceolate, the lower foHaceous; 

 sepals lanceolate, about 3 mm. long, very acute; petals about half as long or less, 

 or lacking. S. alpestris Fries. Wet places: Ont. — -Sask. — Colo. — Utah — Alta.; 

 n Eu. Submont. — Mont. Je-Au. 



5. A. longifolia (Muhl.) Britton. Stem sharply 4-angled, 2-5 dm. high; 

 leaves sessile, lance-linear, often ciliate towards the base, 2-6 cm. long, 2-6 mm. 

 wide; bracts lanceolate; branches of the cjTne and pedicels spreading; sepals 

 lanceolate, acute, 3-nervcd, about 3 mm. long, shorter than the petals. S. longi- 

 folia Mulil. Low meadows and swamps: Lab.- — -Xewf. — Md. — N.M. — Alaska; 

 Eurasia. Plain — Subalp. My-Au. 



6. A. strictiflora Rydb. Stem 2-5 dm. high, angled; leaves linear-lance- 

 olate, 2-4 cm. long, 2-4 mm. wide, spreading; pedicels strongly ascending or 



