EUPHORBIACE^. (SPDKGE FAMILY.) 433 



§ 2. PETAL6MA. Uppermost or floral leaves with conspicuous white petal-like 

 margins, whorled or opposite, the others scattered : erect annuals, with the leaves 

 equal at the base and entire, and with lanceolate deciduous stipules : involucres 

 mostly 5-lobed, collected in an umbel-like inflorescence : no caruncle to the seed. 



9. E. maeginAta, Pursh. Stem stout (2° -3° high), erect, hairy; leaves 

 sessile, ovate or oblong, acute ; umbel with 3 dichotomous rays ; glands of the 

 involucre with broad white appendages. — Prequently cultivated in gardens for 

 its showy broadly white-margined floral leaves : native of the plains of Kansas 

 and Nebraska. 



§3. TITHYMALOPSIS. Only the uppermost or floral leaves whorled or opposite: 

 erect perennials, with entire leaves equal at the base: stipules none: involucres 

 mostly 5-lobed, in thefl>rks of the branches and terminal, in an umbellifltrm inflo- 

 rescence : seeds without caruncle. 



10. E. coroll^ta, L. Glabrous or sometimes sparingly hairy (20-3° high) ; 

 leaves ovate, lanceolate, or linear, entire, obtuse ; umbel 5- (3 - 7-) forked, and 

 the forks again 2-3- (or rarely 5-) forked; involucres long-peduncled ; pod 

 slender-pedicelled, smooth ; seeds thick ( 1 " long or more), ash-colored, the surface 

 slightly uneven. — Rich or sandy soil, New York to Wisconsin and southward. 

 July - Oct. — Conspicuous for the showy false lobes of the involucre, which ap- 

 pear like five white petals, the true lobes minute and incurved. 



B. EXAPPENDICULAT^. Glands of the involucre without petaloid appendages. 



§ 4. POINSETTIA. Involucres in terminal clusters, 4 - 5-lobed, with few {or 

 oflen solitary) cup-shaped glands: seed without a caruncle: ours erect annuals, 

 with variable, entire, dentate, or sinuate leaves, all of them or only the upper ones 

 opposite ; the uppermost often colored, especially at the base : stipules small and 

 glandular. 



11. E. dentita, Michx. Erectorascending, hairy (1° high) ; leaves ovate, 

 lanceolate, or linear, petioled, coarsely toothed (l'-2' long), only the lowest ones 

 alternate, all others opposite, upper ones often paler at base ; involucres almost 

 sessile, with 5 oblong dentate lobes, and one or sometimes more short-stalked 

 glands ; seeds ovate-globular, slightly tubercled. — Rich soil, Ohio to Dlinois and 

 southward. July - Sept. 



12. E. heteroph^Ua, L. Erect (l°-3° high), glabrous; leaves alternate, 

 petioled, ovate-fiddle-shaped and sinuate-toothed, or lanceolate or linear and en- 

 tiro, often only those of the branches linear ; the upper ones usually with a red 

 base ; involucres about the length of the peduncle, with 5 ovate incised lobes 

 and a single or few and almost sessile glands; seeds nearly globular, tubercled. 

 (E. cyatbophora, Joey.) — Slopes and rocky soil, W. Dlinois and southwai'd. 

 July -Sept. 



§ 5. TITHYMALUS. Involucres in a terminal dichotomous or commonly umbelli- 

 form inflorescence, 5- or usually i-lobed, with as many flat or convex entire or 

 crescent-shaped glands: seeds mostly carunadate: ours ascending or erect, and 

 glabrous {except No. \5) annuals or perennials; with entire or serrulate leaves, 

 and no stipules. 



« Perennials with entire leaves, all or only the upper ones opposite : involitcres long- 

 28 



