SPURGE FAMILY 543 



naked or usually with an appendage; one sinus of each involucre usually gland- 

 less. Capsule 3-lobed, smooth, with sharp or rounded angles. Seeds angled, 



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the faces smooth or transversely wrinkled. 



Leaf-blades entire. 



Annuals or biennials. 



Plants prostrate; leaves oblong to orbicular. 



Leaf-blades manifestly longer than broad, usually more than twice as long. 



1. C. Geyeri. 



Leal-blades as broad as long or nearly so. 2 C serpens 



Plants more or less ascending or erect ; leaf-blades linear or linear-lanceolate 

 Capsule less than 1.5 mm. long. 3. c revoluta 



Capsule about 2 mm. long or more. 



Appendages of the glands conspicuous, white. 4. C. petaloidea 



Appendages inconspicuous, greenish white, or obsolete. 



Stems low and erect; stipules subulate-setaceous; seeds flnely granu- 

 late, obscurely angled. 5. C. Parryi. 

 Stems long and ascending; stipules triangular; seeds smooth, 3-angled 



Perennials. 



Leaves glabrous. 



Appendages fan-shaped, white, petaloid; stipules triangular, fimbriate. 



7. C. albomarginata. 

 Appendages crescent-shaped or semi-orbicular, greenish, pinkish, or yellowish ; 



stipules subulate-setaceous. 



Appendages crescent-shaped, much narrower than the gland; leaves broadly 

 deltoid-ovate; seeds transversely ridged; plant prostrate. 



8. C. Greenei. 

 Appendages conspicuous, semi-orbicular, fully as broad as the glands; 



leaves ovate or ovate-lanceolate; seeds irregularly pitted; plant erect. 



9. C. Fendleri. 

 Leaves pubescent. 10. C. lata. 



Leaves toothed, but sometimes only at the apex; stems and branches prostrate; annuals. 

 Capsules glabrous. 



Seeds strongly transversely wrinkled. 11. C. glyptosperma. 



Seeds pitted or irregularly and faintly wrinkled. 



Seeds deeply and irregularly pitted. 12. C. rugulosa. 



Seeds faintly pitted or wrinkled. 



Leaves oblong; seeds usually with a white bloom. 13. C. serpyllifolia. 

 Leaves linear; seeds brownish, usually without a bloom. 



14. C. albicaulis. 

 Capsule pubescent. 



Leaf-blades and involucres glabrous or sparingly pubescent. 15. C. maculata. 

 Leaf-blades and involucres copiously hirsute. 16. C. stictospora. 



1. C. Geyeri (Engelm.) Small. Plant green; stem branched at the base; 

 branches 0.5-4 dm. long; leaf-blades oblong to ovate, 4-12 mm. long, obtuse, 

 usually mucronulate, truncate or subcordate at the base; involucres turbinate, 

 1.5 mm. high; glands 0.3 mm. broad; appendages inconspicuous, white or red; 

 seeds narrowly ovoid, 1.5 mm. long, nearly terete, ash-colored. Euphorbia 

 Geyeri Engelm. On plains and prairies: 111. - - Mo. - - Tex. - - Neb. - - Minn. 

 Plain. Je-S. 



2. C. serpens (H.B.K.) Small. Plant pale green; stems branched at the 

 base, 5-30 cm. long; leaf-blades orbicular to oval, 2-6 mm. long, obtuse or emargin- 

 ate, rounded or subcordate at the base; involucres nearly 1 mm. high; appendages 

 minute, irregular, crenate; capsules nodding, depressed-globose, 2 mm. broml: 

 seeds 1 mm. long, smooth, obtusely 4-angled, light gray. E. serpens H.B.K. 

 On prairies and plains: Ont. Fla. Ariz. S.D.; Mex. Plain Son. Je-O. 



3. C. revoluta (Engelm.) Small. Plant delicate; stem very slender, 8-20 

 cm. high; leaves few; blades narrowly linear, 1-3 cm. long, usually about 1 mm. 

 broad, acute; involucres 1 mm. long; glands minute, broader than long, purple: 

 appendages white or reddish, oblong or ovate, obtuse, entire; capsules about 1 

 mm. long, rather sharply 3-angled; seeds oblong, less than 1 mm. long, sharply 

 4-angled, the faces irregularly wrinkled. E. revoluta Engelm. Hillsides: Ti-x. 

 Colo. N.M.; n Mex. Son. Jl-Au. 



4. C. petaloidea (Engelm.) Small. Plant pale green; stem 1-6 dm. high: 

 leaf-blades linear, oblong or linear-lanceolate, 1-2.5 cm. long, obtuse; involucres 

 oblong-campanulate, 2 mm. long; glands about as long as the lobes; appendage 

 white, reniform, ovate or suborbicular, entire or undulate; capsules globose- 

 reniform, fully 2 mm. long; seeds oblong-ovoid, nearly 2 mm. long, ash-colored, 



