THE POLYPETALOUS ORDERS. 375 



Leaves alternate, stipulate. Cotyledons plane. ROSACEJE, p. 411. 



Leaves opposite, exstipulate, not dotted. CALYCANTHACE.&, p. 414. 



Leaves opposite, exstipulate, pellucid-punctuate. MYRTACEJE, p. 415. 



* * Calyx free from the comp. ovary. Stam. definite. LYTHRACEJE, p. 416. 



* * * Calyx-tube adnate to the compound ovary. Stamens definite. 



Anthers opening by a pore at the apex. MELASTOMACE^E, p. 416. 

 Anthers opening longitudinally. 



Stipules interpetiolar. Leaves opposite. RHIZOPHORACEJE, p. 416. 

 Stipules none. Calyx valvate. 



Cotyledons convolute. COMBRETACE.S, p. 416. 



Cotyledons plane. ONAGRACEJE, p. 416. 



Group 17. Ovary compound, one-celled, with parietal placentae. Petals and 

 (with one exception) stamens inserted on the throat of the calyx. Flow- 

 ers perfect, except in Papayacese. 



* Calyx adherent to the ovary. 



Albumen none or very little. Petals and stam. indefinite. CACTACE.E, p. 418. 

 Albumen very copious. Embryo minute. Stam. 5. GROSSULACEJE, p. 418. 

 Albumen present: embryo rather large. Stam. indefinite. LOASACE.E, p. 419. 



* * Calyx free from the ovary. 

 Flowers perfect. Stamens 5. 



Stamens distinct, perigynous. TURNERACE.S:, p. 419. 



Stamens monadelphous, adnate to the gynophore. PASSIFLORACEJE, p. 419. 



Flowers dioecious. Stamens 10, on the corolla. PAPAYACE.*:, p. 420. 



Group 18. Ovary compound, 2- several-celled (or one-celled by obliteration) ; 

 the placentae parietal, arising from the axis, but carried outwards to the 

 walls of the pericarp. Calyx adnate. Corolla frequently monopetalous. 

 Stamens united either by their filaments or anthers. Flowers dioecious 

 or monoecious. Albumen none. CUCURBITACEJE, p. 420. 



Group 19. Ovaries two or more, many ovuled, distinct, or partly, sometimes 

 completely, united, when the compound ovary is one-celled with parietal 

 placentae, or 2 -many-celled with the placentae in the axis. Calyx either 

 free from the ovary, or adherent. Petals and stamens inserted on the ca- 

 lyx ; the latter mostly definite. Seeds albuminous, numerous. 



Pistils as many as the sepals. CRASSULACEJE, p. 421. 



Pistils fewer than the sepals, more or less united. SAXIFRAGACE^E, p. 422. 



Group 20. Ovary compound, 2- (rarely 3-5-) celled, with a single ovule sus- 

 pended from the apex of each cell. Stamens usually as many as the pet- 

 als, or the lobes of the adherent calyx. Embryo small, in hard albumen. 



* Summit of the (often 2-lobed) ovary free from the calyx; the petals and 



stamens inserted on the throat of the calyx. HAMAMELACE^E, p. 423. 



* * Calyx-tube entirely adherent to the ovary. Stamens and petals epigy- 



nous. Flowers umbellate. 



Fruit separable into two dry carpels. UMBELLIFER.E, p. 423. 



Fruit drupaceous, usually of more than two carpels. ARALIACE^, p. 425. 



Flowers cymose or capitate. Drupe 2-celled. CORNACE.E, p. 425. 



