338 



SYSTEMATIC BOTAXY. 



scent ; seeds suspended, 1 or 2 in each cell, often with an arillus ; 

 embryo m fleshy perisperm ; radicle superior. 



This Order is divided by Miiller into two main divisions, according to 

 the^size and breadth of the cotyledons, the number of the ovules the 

 aestivation of the calyx, &c. Baillon divides them according to the num- 

 ber of the ovules in the first instance, the presence or absence of perisperm, 

 the presence of an " obturator " or process of the placenta, the sexual con- 

 dition of the flowers, &c. 



ILLUSTRATIVE GENERA. 

 Hura, L. 

 Hippomane, Z. 

 Ccelebogyne, J, Sm. 

 Mercurialis, L. 

 Acalypha, L. 



Affinities, &c As the more familiar forms of this Order are either 

 apetalous, or even destitute of a calyx, it is usuallv arranged among the 

 Monocnlamydew in elementary works ; but a large proportion of the 

 exotic genera have the corolla represented either by scales or petals. 

 -V le common & P ur o es (Euphorbia}, the principal native representatives of 

 the Urder, have a very remarkable inflorescence, or " cyathium," by some 

 considered as a, simWl flniiroT- . +ii<va i c , . 1:1 : ,.i / i _ 



, , 



considered as a simple flower; there is a cup-like involucre (calyx ac- 

 ts to Linnaeus's original idea), within "which 



cording to Baillon, who reverts , n wc 



are formed a number of stamens with an articulation in the filament, 

 together with a stalked tricarpellary ovary (fig. 429). Each one of the 



Fig. 429. 



Pig. 430. 



Fig. 429. a, Vertical section of the involucre of Euphorbia Lathyris, containing one stalked 

 pistillate flower and six monandrous staminate flowers; b, b, staminate flowers 

 of other species of Euphorbia, the left-hand without a perianth, the right with 

 a small perianth at the base of the stamen. 



Fig. 430. Monotaxis trident ata: a, involucre, with one pistillate and several staminate 

 flowers; 6, a separate staminate, c, a separate pistillate flower. 



stamens, according to R. Brown and many others, represents a male 

 flower reduced to its lowest term ; for a minute bract exists at the base 

 of each filament, and in some species a perianth occurs at the articulation, 

 which is, in fact, the base of the flower : the ovary in like manner repre- 

 sents a female flower. This is well illustrated by the exotic genus Mono- 



