SPURGE FAMILY 151 



Leaves alternate or scattered, at least below the inflorescence; annuals or bien- 



eniais; bracts petal-like. 6. Lepadenia. 



Glands of the involucres without petal-like appendages, entirely naked, sometimes 



with crescent-shaped horns. 

 .Stem topped by an umbel; stipules none; involucres in open cymes, each with 4 



glands and entire or toothed lobes. 7. Tithyaialus. 



Stem not topped by an umbel; stipules gland-like; involucres in conglomerate 



cymes, each with a single gland, or rarely 4 glands and flmbriate lobes. 



8. POINSETTIA. 



1. CROTON L. Croton. 



Annual; leaf-blades linear, lanceolate, or oblong, 3-5 times as long as the petioles. 



1. C. texensis. 

 Perennial; leaf-blades elliptic or oval, only a little longer than the petioles. 



2. C. longipes. 



2. DITAXIS Vahl. l. D. humilis. 



3. TRAGIA fPlum.) L. l. T. nimosa. 



4. CHAMAESYCE S. F. Gray. Spurge, Carpet-weed. 

 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. 

 Leaf-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 nun. long. 3. C. revoluta. 



Capsule about 2 nam. long or more. 



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



Appendages inconspicuous, greenish white, or obsolete. 



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

 late, obscm-ely angled. 5. C. Parryi. 

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



6. C. flagclliformis. 

 Perennials. 



Leaves glabrous. 



Appendages fan-shaped, wliite, petaloid; stipules triangular, flmbriate. 



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; armuals. 

 Capsules glabrous. 



Seeds strongly transversely wrinkled. 11. C. glyplosperma. 



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. serpylli folia. 

 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. 



5. ZYGOPHYLLIDIUM Small. Spurge. 



Leaves entire; appendages of the glands triangular-ovate. 1. Z. hexagonum. 



Leaves serrate; appendages of the glands semi-orbicular. 2. Z. exslipulatum. 



6. LEPADENIA Raf. Snow-on-the-mountain. l. L. marginala. 



7. TITHYMALUS (Tourn.) Adans. Spurge. 



Leaves entire; glands of the involucres with processes, except in the flrst species. 

 Perennials with a woody base; processes short and blunt, or none. 



Stem-leaves linear; capsule rough; seeds smooth. 1. T. Cyparissias. 



Stem-leaves from oblong or oblanceolate to orbicular; capsule smooth or slightly 

 wrinkled; seeds pitted. 

 Glands crenulate, obscurely horned; leaves small, ascending. 



2. T. luridus. 

 Glands distinctly horned; horns larger than the teeth (if any) between them; 

 leaves large, spreading. 

 Bracts rhombic-ovate, cuspidate; stem rather slender. 3. T. philorus. 

 Bracts rhonibic-reniform, mucronate; stem stout. 4. T. robustus. 



