136 FOUNDATIONS OF BOTANY 



I. EUPHORBIA, L. 



Herbs or shrubs, with milky juice, often poisonous. 

 Flowers monoecious, enclosed in a 4-5-lobed involucre, which 

 is often showy and resembles a calyx or corolla, usually bear- 

 ing large glands at its notches. Sterile flowers many, borne 

 inside the involucre at its base (Fig. 16, J), each consisting only 

 of a single stamen attached by a joint to a pedicel which 

 looks like a filament. Fertile flower standing alone at the 

 center of the involucre (Fig.l6, C) (soon pushed out by the 

 growth of its pedicel), consisting only of a 3-lobed and 

 3-celled ovar}^, 3 2-cleft styles, and 6 stigmas. Pod 3-celled 

 and 3-seeded. 



A. Cultivated shrubs. 



1. E. splendens, Bojer. Crown of Thorns. An extremely 

 prickly shrub, with many erect, few-leaved branches. Leaves 

 obovate or obovate-spatulate, mucronate, entire, each with two very 

 sharp prickles (longer than the petiole) as stipules. Peduncles long, 

 sticky, each bearing 2-4 objects, which appear to be showy scarlet 

 flowers, but which are actually 2-bracted involucres containing the 

 true flowers. Involucral scales somewhat kidney-shaped, mucronate. 

 Flowering all the year round. Cultivated in greenhouses. From 

 Mauritius. 



B. Herbs with leather showy ichite jiower-clusters. 



2. E. coroUata, L. rLOWp:RiNG Spurge. Perennial. Stem 

 erect, umbellately branched above, smooth or downy, 1-3 ft. high. 

 Leaves of the stem alternate, those of the branches usually opposite 

 or whorled, rather thick, oval to narrowly oblong, pale beneath, 

 usually slightly downy. Flowering branches repeatedly forked ; 

 involucres terminal and in the forks of the branches, peduncled ; 

 glands 4-5, oblong, green ; appendages white and petal-like, showy. 

 Capsule erect, seed smooth or faintly pitted. Common in dry, open 

 woods. 



C. Herbs: No. 3 a native species, No. ^ cultivated from Europe or 

 escaping from c/ai'dens. Flower-clusters in umbels not white. Involucre 

 Jf, or 5 lobed, each lobe ivith a gland. 



3. E. dictyosperma, Fischer and Mayer. Annual. Stem slender, 

 8-18 in. high, erect. Stem-leaves oblong-spatulate to obovate, ser- 

 rate ; floral ones roundish-ovate, somewhat heart-shaped. Flower- 

 cluster a compound umbel, the rays once or twice 3-forked, then 

 2-forked. Seeds covered with a network. Prairies and roadsides. 



