DICOTYLEDONRS : POLYPETAL^ : DISCIFLOR^E, 



621 



fcions or dioecious ; the perianth sometimes consists of calyx and 

 corolla, sometimes it is simple, and occasionally it is absent : the 

 ovary is nsually trilocular, with one or two anatropous and gener- 

 ally suspended ovules in each loculus: the seed contains endosperm : 

 the structure of the flowers is very various. The affinities of the 

 cohort are not accurately known ; but it can no longer be retained 

 among th^ Monochlamydeae. 



Order 1. EuPHORBiACEiE. The flower exhibits all possible de- 

 grees of reduction. The perianth may consist of calyx and corolla 

 {e.g. some Phyllanthese, such as Andrachne, Savia, Bridelia ; some 

 Crotoneee, such as Chrozophora, Croton sub-gen. Eluteria, Ja- 

 tropha, Cluytia, etc.) : more commonly the corolla is suppressed, 

 and in some cases {e.g. Euphorbia) the calyx also. The andrcecium 

 varies from 1 to 8 stamens: thus in 

 Euphorbia the ,^ flower consists of a 

 single stamen, whilst in Ricinus the 

 stamens are numerous and repeatedly 

 branched (Fig. 333) : they are some- 

 times isomerous with the perianth- 

 leaves. The gynseceum is typically 

 trimerous, but the carpels may be more 

 numerous (5-20 in Hura) or fewer (1 

 in Eremocarpus) : the syncarpous ovary 

 has as many loculi as there are car- 

 pels : each loculus contains one or two 

 (then collateral) suspended anatropous 

 ovules, the micropyles of which are 

 directed outwards ; the micropyle is 

 usually invested by a micropylar aril 

 (see p. 459), often termed the caruncle, 

 which is conspicuous on the seed. The 

 fruit is usually dry and dehiscent, splitting septici dally into cocci. 

 A disc is commonly present, and is frequently annular in the 9 

 flowers : in the ^ flowers the disc is usually extra-staminal. 



They are plants of various habit, from herbs to trees, some 

 resembling species of Cactacese. Many of them possess laticiferous 

 tissue (absent in Phyllanthees and some Stenolobeee), consisting 

 either of laticiferous coenocytes (Euphorbieee : see p. 142) or of 

 laticiferous vessels (Crotoneee) : the latex is usually milky, and in 

 this case the laticiferous tissue is more highly developed than 

 when (as in Mercurialis) the latex is not milky. 



FlO. 4?o.— Part of an inflores- 

 cence of a Euphorbia : b b bracts, 

 in the axils of which are the 

 buds (fcn) : p is the involucre 

 of the open cyathium ; dr the 

 glands; a the <J flowers; g the 

 pedicel of the $ flower (/) ; n the 

 stigmata (enlarged). 



