84 PAM. 101, 102, 103. 



M. utilissima, Bitter Cassava. Anthers short; capsule wing-angled; — roots 

 contain poisonous juice which is pressed out or rendered harmless by heat- 

 ing; tapioca is made from the rootstarch. 



M. palmata, Sweet Cassava. Anthers elongated; capsule only angular above, 

 not winged; — roots more reddish colored and not poisonous. 

 12. Glands of the involucre with petal-like appendages, which may be 

 much reduced; — stems branched at the base; leaves all opposite, 

 with delicate entire or fringed stipules; involucres solitary in 

 the axils or in axillary cymes; glands 4, one sinus of each invol- 

 ucre being without a gland, - Chamaesyce (Euphorbia) 



C. (E.) maculata. Dark green, pubescent, with prostrate often dark-red branches 

 and oblong leaves, usually blotched; involucres solitary in the axils, the 

 glands with narrow, white or red appendages. Waste places. Spring to 

 Fall. 



12. Glands of the involucres without petal-like appendages, - - - 13 



13. Stem simple or branched, topped by an umbel; leaves below the 



umbel alternate or scattered; no stipules; bracts of the umbel 

 different from the stem-leaves; involucres axillary, in cymes; 

 glands 4, and a thin often ciliate lobe instead of the fifth, 



Tithymalus (Euphorbia) 

 T. inundatus (E. inundata). Stem topped by a 2-3 rayed umbel and simple or 

 branched below it; leaves alternate; glands reniform. In pine-land swamps. 

 Early Summer. 

 13. Stem not topped by an umbel; leaves alternate below, opposite 

 above; stipules gland-like; — herbs or shrubs often with colored 

 foliage, leaves all similar; involucres solitary or in cymes; glands 

 1, rarely 3 or 4, the missing ones represented by narrow lobes, 



Poinsettia (Euphorbia) 



P. heterophylla, Painted leaf, Hypocrit. Stems erect with spreading branches; 



leaves linear, ovate or obovate; leaves and bracts blotched with red. 



Sandy soil. Spring to Fall. 



P. (E.) pulcherrima. A tall tropical plant with large scarlet bracts subtending 



the flowers. Cultivated. Winter and Spring. 

 Other Euphorbias are cultivated in pots, as the twining E. splendens, Crown 

 of thorns; the stem covered with stout spines; leaves few, bright green; flowers in forked 

 cymes, closely subtended by two bright red, ovate bracts. 



Pedilanthus tithymaloides, Bird-cactus. Baby-foot, a shrubby plant with zig- 

 zag fleshy stem and branches; the red involucres, oblique and strongly 2- 

 lipped, in contracted cymes; stamens and style exserted. 



102. Callitrichaceae, Water -Starwort Family, 



Small herbs, mostly aquatic, with opposite, entire 

 leaves; flowers polygamous, axillary, solitary; perianth 

 wanting; 1 stamen, 2 styles, ovary 4-celled with ovules 

 solitary in each cell; fruit a leathery capsule. 



C. peploides. Stems branching, forming wide mats on moist earth. Spring. 

 103. Empetraceae, Crowberry Family. 



Evergeeen shrubby plants with erect or prostrate stems; 

 leaves alternate or whorled, narrow, revolute; flowers 



