16B NATURAL HISTORY OF PLANTS. 



interior when the filament is erect ; on the consistency of the 

 l^ericarp, sometimes dehiscent and sometimes indehiscent ; and finally 

 on the presence or absence of an arilate thickening, more or less 

 general or limited to the neighboTU'hood of the micropylar regions 

 (caruncula) ; all characters, which we see, are sufficient at need to 

 distinguish two genera from one another, when there are also other 

 important differences between them, but which generally are not 

 sufficient of themselves to distinguish the groups of a higher 

 order. 1 Finally we have preserved the following series which we 

 characterize as follows : 



A. Uniovulate Euphorbiacese. 



I. EuPHORBiE^. — Flowers generally hermaphrodite, regular or 

 ii'regular, with involucriform calyx, provided with glands alternate 

 with its divisions. Stamens co, with articulate filaments, inserted 

 around a stipitate gynaecoum, whose ovary is or is not accompanied 

 at its base by an hypogynous disk. Glands or bracteoles arranged 

 inside the perianth in bundles alternate with the staminal bundles. 

 — 2 genera. 



II. EiciNEiE. — Flowers unisexual, apetalous. Stamens in indefinite 

 numbers, polyadelphous, central or peripheric. — 3 genera. 



III. Jatrophe^. — Flowers unisexual, with or without petals. 

 Calyx valvato or imbricate, with or without glandular disk. Stamens 

 in number definite or indefinite, inserted in the centre of the flower 

 or around a central body. Staminal filaments rectilinear, upright, 

 or slightly incurvate, sometimes folded in the bud. — 88 genera. 



IV. — Crotone^. — Flowers unisexual, with or without petals and 

 provided with a glandular disk. Calyx valvate or imbricate. 

 IVumber of stamens nearly always indefinite, inserted on verticils in 

 the centre of the projecting floral receptacle, with introrse anthers, 

 infracto-incurvate in the bud on account of the cui'vatnre of the 

 filament.^ — 4 genera. 



V. — Exo^CARiEiE. — Flowers unisexual,' apetalous nearly always 

 trimerous and calyx usually imbricate, generally destitute of glandular 

 disk. Stamens central, alternate with the divisions of the calyx when 

 they are (which is usual) in equal number. Flowers usually arranged 



Sui; Ailunsoiiiii, xi. 72. - Really extrorsu before anthesis. 



