102 



LXXXVIII. EUPIIORBIACE/E. The Eupiiorbium Tribe. 



EupHORBi.t, Jmss. Gen. 385. (17f50). — EupHORBiACEiE, Ad. deJuss. Monogr. (1824); 

 Litidl. Syiiops. 220. (1829.) 



Diagnosis. Apetalous dicotyledons, with definite suspended ovules, 

 a 3-celled ovarium, unisexual flowers, and embryo in the midst of oily 

 albumen. 



Anomalies. Carpella occasionally 2, or more than 3. 



Essential Character — Flotcers monoecious or dicecious. Calyx lobed, inferior, 

 with various glandular or scaly internal appendages ; (sometimes wanting). Males : Sta- 

 mens definite or indefinite, distinct or monadelphous ; anthers 2-celled. Females : Ova- 

 rium superior, sessile, or stalked, 2- '.^- or more celled; ovules solitary or twin, suspended 

 from the inner angle of the cell ; styles equal in number to the cells, sometimes distinct, 

 sometimes combined, sometimes none ; sthpna compound, or single with several lobes. 

 Fruit consisting of 2, 3, or more dehiscent cells, separating with elasticity from their 

 common axis. Seeds solitary or twin, suspended, with an arillus ; embryo enclosed in 



fleshy albumen ; cotyledons flat ; radicle superior Trees, shrubs, or herbaceous plants, 



often abounding in acrid milk. Leaves opposite or alternate, simple,, rarely compound, 

 usually with stipulse. Floivers axillary or terminal, usually with bractea;, sometimes 

 enclosed within an involucrum. 



Affinities. If the group of apetalous orders be considered a natural 

 one, Euphorbiacese will stand by the side, or in the vicinity, of Urticese, with 

 which, however, they have few points in common, except the want of a 

 corolla; or near Myristicese, with which the columnar stamens of many 

 species, and the acridity of their juice, may be said to accord. But it is 

 probable that the real relationship of the order is of a very different kind. 

 Jussieu long ago perceived a resemblance between Euphorbiaceae and 

 Rhamnese, a resemblance which A. Brongniart has since adverted to {Monogr. 

 des Rhamn. p. 35); and which chiefly depends upon a similarity in habit, 

 an embryo wi;h flat foliaceous cotyledons, solitary seeds, a great reduction in 

 size of the petals of Rhamneae, as if the order was tending towards an 

 apetalous state, and a frequent division of the fruit into three parts. 

 Auguste St. Hilaire {PL Usuelles, no. 18.) inquires whether they are not 

 intermediate between Menispermese and Malvaceae. There can be no 

 doubt of their relation to the latter, that is to say, to the orders of poly- 

 petalous dicotyledons with hypogynous stamens and a valvate calyx, if we 

 consider their general habit, especially that of the Crotons, the presence of 

 abundance of stellate hairs, and their definite seeds ; but these points are 

 not sufficient to approximate the orders very nearly : in fact, the true 

 affinities of Euphorbiaceac cannot be said to be at present well understood. 

 Ach. Richard suggests some affinity with Terebiutacea;, as well as Rham- 

 neae. EUmens, ed. 4. 558. 



Geography. This extensive order, which probably does not contain 

 fewer than 1500 species, either described or undescribed, exists in the greatest 

 abundance in equinoctial America, where about 3-8ths of the whole number 

 have been found ; sometimes in the form of large trees, fre(|uently of bushes, 

 still more usually of diminutive weeds, and occasionally of deformed, leafless, 

 succulent plants, resembling the Cacti in their port, but diflering from them 

 in every other particular. In the Western world they gradually diminish as 

 they recede from the equator, so that not above 50 species are known in 

 North America, of which a very small number reaches as far as Canada. 

 In the Old World the known tropical })roportion is much smaller, arising 

 probably from the species of India and e<|uinocti.d Africa not having been 

 described witii ihc same care as those of America ; not above an eighth 



