EUPHORBIACEAE. 



217 



1. Tithymalus Peplus (L.) Hill. 

 Petty Spurge. (Fig, 242.) Annual, 

 bright green, glabrous. Stem erect or 

 assurgent. 4-12' tall, simple or branched 

 from the base or above and topped by a 

 3-5-rayed umbel; leaves alternate, ob- 

 long or obovate, V-IV long, obtuse or 

 retuse, entire, more or less crisped, nar- 

 rowed into slender petioles; bracts of 

 the rays opposite, ovate or triangular- 

 ovate, minutely apiculate, sessile; in- 

 volucres campanulate, almost sessile in 

 the axils of the bracts, about i" high, 

 bearing 4 crescent-shaped glands pro- 

 duced into subulate horns; capsules glo- 

 bose-ovoid, 1"-!^" in diameter, smooth, 

 the 3 lobes 2-keeled on the back; seeds 

 f" long, whitish, marked with 1-4 series 

 of pits. [Euphorbia Peplus L.] 



Common in waste and cultivated 

 ground. Naturalized. Native of Europe. 

 Naturalized in North America. Flowers 

 from spring to autumn. 



10. POINSETTIA Graham. 

 Annual or perennial herbs or shrubby plants, with green or partially 

 highly colored foliage. Stems simple or branched. Leaves alternate below, 

 opposite above, similar throughout or very various, the stipules gland-like. 

 Involucres in axillary or terminal cymes or solitary, their lobes fimbriate. 

 Glands fleshy, solitary, or rarely 3 or 4, sessile or short-stalked, without ap- 

 pendages, the missing ones represented by narrow lobes. Capsule exserted, the 

 lobes rounded. Seed narrowed upward, tuberculate. [In honor of Joel Roberts 

 Poinsette of South Carolina.] About 12 species mostly of tropical America. 

 Type species: Poinsettia pulcherrima (Willd.) Graham. 



Perennial : native. 

 Annual weed. 



1. P. Jirterophylla. 



2. r. ci/(itli()iilwni. 



1. Poinsettia heteroph^lla (L.) 

 Kl. &■ Garcke. Various-le.wed Spurge. 

 Joseph's Coat. (Fig. 243.) Peren- 

 nial, bright green. Stem l°-4° tall, 

 slender, nearly solid, the branches as- 

 cending, or the lower spreading, leafy 

 at the ends; leaves alternate, very vari- 

 able, linear to nearly orbicular, entire, 

 undulate, sinuate or dentate, the upper- 

 most often fiddle-shaped and blotched 

 with red and white ; involucres clus- 

 tered at the ends of branches, IV' long; 

 lobes 5, ovate or oblong, laciniate. the 

 sinuses bearing 1 or several sessile 

 glands; capsule glabrous or minutely 

 pubescent, 3" in diameter; seeds trans- 

 versely wrinkled and tuberculate. [Eu- 

 phorbia heterophifUa L.] 



Frequent on rocky hanks, cliffs and 

 hillsides, sometimes invading cultivated 

 grounds. Native. Southern I'nited Stiues. 

 West Indies and tropical continental 

 America. Flowers nearly throughout the 

 year. 



