716 EUPHOKBIACEAE 



b. Involucres 6-10 mm. across the appendages. 9. T. zinniiflora. 



B. Inflorescence aggregated into terminal cymes or cymose clusters. 



Leaf-blades manifestly petioled, the petioles over 2 mm. long. 10. T. apocynlfolia. 



Leaf-blades sessile or nearly so, the petioles, if present, less than 1 mm. 



long. 



Involucres 3.5 mm. across the appendages or narrower. 11. T. discoidalis. 



Involucres 4-8 mm. across the appendages. 



Appendages about as long as the involucre. 12. T. olivacea. 



Appendages much longer than the involucre. 



Appendages longer than wide : leaf-blades relatively narrow. 13. T. corollata. 

 Appendages as wide as long or wider : leaf-blades relatively 



broad. 14. T. paniculata. 



1. Tithymalopsis polyphylla (Engelm. ) Small. Perennial, glabrous. Stems tufted 

 or branched at the base, the branches erect or spreading, 0.5-2.5 dm. long, simple or more 

 or less branched : leaves numerous, approximate, linear or linear-spatulate, 5-15 mm. long, 

 straight or slightly curved, sessile : bracts oblong or linear-oblong : involucres turbinate- 

 campanulate, about 1.5 mm. high, abruptly contracted at the base, shorter than the pedun- 

 cles at maturity : glands 0.5-0.6 mm. broad ; appendages white or pinkish, reniform or 

 mere undulate or crenate borders : capsules globular, 4-4.5 mm. in diameter : seeds oval, 

 2.5 mm. long, smooth, white. [Euphorbia polyphylla Engelm.] 



In sand, southern peninsular Florida. 



2. Tithymalopsis Ipecacuanhae (L. ) Small. Perennial by a subterranean stem and 

 root, usually glabrous. Branches several or many, slender, spreading or ascending, 1-3 dm. 

 long, forking : leaves mostly opposite, green or red ; blades wonderfully variable in outline, 

 from linear to orbicular, 1-7 cm. long, entire, the upper sometimes whorled, the lower 

 sometimes alternate, short-petioled ; stipules triangular : involucres axillary, mostly hem- 

 ispheric, about 2 mm. long, slender-peduncled ; bearing 5 transversely elliptic or oblong, 

 green, sessile, narrowly appendaged glands : capsules 3 mm. in diameter, nodding : seeds 

 light gray, oblong-ovoid, about 2.5 mm. long, pitted, obscurely 4-sided. 



In dry sandy soil, Connecticut to Florida, mostly near the coast. Also in southern Indiana. 

 Spring to fall. 



3. Tithymalopsis gracilis (Ell. ) Small. Perennial , glabrous. Branches wiry, tufted, 

 1-3 dm. long, trichotomous or dichotomous : leaves mainly opposite ; blades suborbicular 

 to ovate or linear, or rarely broader than long, 1-5 cm. long, obtuse or retuse, or in the 

 case of narrow ones acute, all entire, sessile or nearly so ; stipules triangular : peduncles as 

 long as the accompanying leaves or longer : involucres campanulate or turbinate-campan- 

 ulate, 2 mm. high : glands transversely oblong, less than 1 mm. broad, undulate and nar- 

 rowly appendaged : capsules exserted, drooping, 2.5 mm. in diameter. 



In sand, South Carolina to Georgia and Florida. Spring to fall. 



4. Tithymalopsis eriogonoides Small. Perennial, deep green, glabrous. Branches 

 several or many together, 1-3 dm. long, diffusely branched into a rounded head 1-3 dm. in 

 diameter, the branches very slender, zigzag, the ultimate divisions nearly filiform : leaves 

 opposite above, the larger ones often reflexed ; blades linear or linear-spatulate, 0.5-1.5 mm. 

 long, obtuse or acutish, entire, barely petioled : peduncles filiform, 3-8 mm. long at 

 maturity : involucres campanulate, about 1 mm. high, erect or ascending : glands reni- 

 form, about 0.5 mm. broad ; appendages somewhat reniform, white or pink, about 1 mm. 

 broad, longer than the gland, some rounded, others emarginate. [Euphorbia eriogonoides 

 Small.] 



In loose sand, eastern Georgia and Florida. Spring and summer. 



5. Tithymalopsis mercurialina (Michx. ) Small. Perennial, bright green, nearly 

 glabrous. Stems erect or decumbent, often several together, glabrous except a few scattered 

 hairs about the nodes, forking above : leaves reduced to scales at the base of the stem : 

 bracts foliaceous, opposite ; blades oval, elliptic or oblong-ovate, 2-5 cm. long, entire, 

 somewhat undulate, obtuse, glabrous, except the ciliate margin, rather abruptly narrowed 

 at the base, short-petioled : peduncles nearly filiform, 1-5 cm. long : involucres campanu- 

 late, 2 mm. high, erect or nearly so : glands transversely oblong, about 1 mm. broad ; 

 appendages white, undulate, narrower than the gland : capsules exserted beyond the 

 involucre. [Euphorbia mercurialina Michx.] 



On hillsides and sandy soil, Tennessee to Alabama and Florida. Spring and summer. 



6. Tithymalopsis Curtisii ( Engelm. ) Small. Perennial, glabrous. Stems slender, 

 solitary or several together, erect or ascending, 1-4 dm. tall, more or less branched : leaves 

 scattered except the whorl subtending the umbel 3-5-rayed ; blades linear, 1.5-4 cm. 

 long, usually acute : involucres campanulate, about 1 mm. high, much shorter than 

 the nearly filiform peduncles : glands green, transversely oblong, about 0.5 mm. broad ; 

 appendages white, petal-like, much larger than the gland, undulate : capsules subglobose, 



