72 



Introduction to Botany. 



EUPHORBIACE^. Spurge Family. 



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Herbs, sometimes shrubs or trees, with millcy secretions. Flowers 

 monoecious or dioecious. Flowers mostly apetalous, and sometimes 



much reduced and subtended by an 

 involucre, which resembles a calyx. 

 Stamens few to many, filaments some- 

 times united. Ovary usually 3-celled, 

 with 1-2 ovules in each cavity. Fruit 

 usually a 3-lobed capsule, dehiscing 

 elastically when mature. (Fig. 349.) 



I. EUPHORBIA. Spurge. 



(Named for Euphorbus, physician to King Juba.) 



Flowers without a calyx and clus- 

 tered in a cup-shaped, calyxlike invo- 

 lucre, the cluster easily mistaken by the 

 beginner for a single flower. The 

 flowers of two kinds within the invo- 

 lucre, many staminate flowers consist- 

 ing of a single stamen, and a single 

 pistillate flower consisting of a single 

 3-lobed pistil protruding above the 

 staminate flowers. Styles 3 and stig- 

 mas 6. 



DiHgrams of the inflorescence of a 

 Euphorbia, i, a single inflores- 

 cence with petal-like involucre and 

 protruding pistillate flower. -2., a 

 staminate flower and accompany- 

 ing bract, which is supposed to rep- 

 resent the calyx. 3, longitudinal 

 diagram of an inflorescence, show- 

 ing the pistillate and four stami- 

 nate flowers. 4, cross diagram of 

 an inflorescence, showing the 

 ovary of the single pistillate flower 

 surrounded by staminate flowers. 

 Around all there is the involucre. 



I. Euphorbia serpens, H. B. K. (L., ser- 

 pens, creeping.) ROUND-LEAVED SPREAD- 

 ING Spurge. Annuals, branching from the 

 base, the branches prostrate, slender, 2 to 12 

 inches long. Leaves orbicular, ovate, or oval, 

 often less than \ inch long, less than twice as 

 long as broad. Stipules triangular and mem- 

 branaceous. In open places. 

 ■i. Euphorbia coroUata, L. (L., cora/Za, a little crown.) Flowering SPURGE. 

 Perennials from stout rootstocks, i to 3 fret tall, unibeliately branched above. 

 Leaves ovate, lanceolate, or linear, only tlie uppermost opposite or \\'horled. 

 Involucre with showy white appendages appearing like petals. In dry soil. 

 3. Euphorbia marginata, Pursh. (L., inarginatiis, provided with a border.) 



