378 NATURAL HISTORY OF PLANTS. 



ovulate ovary cells, rarely co -ovulate. Embryo exalbuminous. Leaves 

 alternate (rarely opposite), often compound pinnate. — 40 genera. 



4. Pancovie^.^ — Polygamo-dioecious irregular flowers. Petals fewer 

 in number (4') than the sepals (5). Irregular, incomplete, unilateral 

 disk exterior to the androceum. Gynseceum excentric, with 1-2- 

 ovulate ovary cells, rarely oo-ovulate. Embryo exalbuminous. 

 Leaves alternate, generally compound-pinnate. — 22 genera. 



5. ^SCULE^. — Flowers irregular, polygamo-dioecious. Petals the 

 same or fewer in number (4) than the sepals, joined more or less 

 high. Gynseoeum slightly excentric. Ovary cells 2-ovulate. Fruit 

 capsular. Seeds exarillate. Embryo exalbuminous, conferruminate. 

 Leaves opposite, compound-digitate. — 2 genera. 



6. MEI.IANTHE-2E. — Flowors irregular, polygamo-dicecious. Andro- 

 ceum irregular, exterior to the disk. Ovules oo. Fruit capsular or 

 vesicular. Seeds albuminous, with or without aril. Embryo straight. 

 Leaves alternate, pinnate, provided with stipules. — 3 genera. 



7. AiTONiE.^;. — Flowers regular, 4-merous. Calyx gamosepalous. 

 Stamens monadelphous, exterior to a cupula-shaped disk. Fruit 

 capsular, vesicular. Cells 1-2-spermous. Seeds exalbuminous. 

 Embryo bent. Leaves simple, alternate, or fasciculate. Flowers 

 axillary. — 1 genus. 



8. AcERE^. — Flowers regular, polygamous or dioecious. Calyx 

 and corolla isomerous (or apetalous flowers). Stamens more or less 

 interior with reference to the cii'cular disk, regular or equally lobate. 

 Ovary with 1-2-ovulate cells. Fruit dry, with indehiscent cells 

 (usually samaroid). Seeds destitute of aril and albumen. Leaves 

 simple or compound-pinnate, opposite. — 2 genera. 



The variable characters employed to distinguish the series are 

 then principally : the situation of the leaves, alternate or opposite, 

 simple or compound, and, in the latter case, pinnate or digitate ; the 

 regularity or irregularity of the flowers, the petals being equal 

 to the sepals or else four in number, and the place of one of them 

 remaining unoccupied, while the calyx is pentamerous ; the regu- 

 larity or irregularity of the disk surrounding the gyn^ceum or only 

 occupying one of its sides ; its position, relatively to the stamens to 

 which it is generally exterior, while, more rarely, its elements are 

 interposed to them or even become interior to the androceum, that is 

 to say, placed close against the foot of the gyngeceum ; the situation 

 of this which is either central or excentric ; the organisation of the 



