EXOGENOUS OR DICOTYLEDONOUS PLANTS. 379 



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



Anthers opening by a pore at the apex. Melastomace^. 

 Antliers opening longitudinally. 



Stipules between the petioles. Leaves opposite, Rhizophoeacea;, 

 Stipules none. Calyx valvate. 



Cotyledons convolute. Fruit indehiscent, 1-celled, Combretace^e. 



Cotyledons plane. Fruit mostly 2- 4-celled. Onagrace^. 



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

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

 perfect, except in Papayacese. 



* Calyx adherent to the ovary. 



Albumen none or very little. Petals and stamens indefinite, Cactace^. 



Albumen very copious. Embryo minute. Stamens 5. GROSSULACEiE. 



Albumen present. Embryo rather large. Stamens indefinite. Loasace.^, 



* * Calyx free from the ovary. 

 Flowers perfect. Stamens 5. 



Stamens distinct and perigynous. Turnerace^, 



Stamens monadelphous, adnate to the gynophore. Passiflokace^, 



Flowers dicecious. Stamens 10, on the corolla. Papayace.*;. 



Group 18. Ovary compound, one - several-celled, the placentas parietal (cither 

 truly or falsely so). Calyx adnate. Corolla frequently monopctalous. 

 Stamens mostly united either by their filaments or anthers. Flowers 

 dia'cious or monoecious. Albumen none. Succulent or tender vines with 

 tendrils. CucuRBiXACEiE. 



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

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

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

 free from the ovary or more or less adherent to it. Petals and stamens 

 inserted on the calyx ; the latter mostly definite. Seeds albuminous, nu- 

 merous. 



Pistils of the same number as the sepals, CrassulacejE, 



Pistils fewer than the sepals, more or less united, SAXiFRAGACEiE, 



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 tlie 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 sta- 



mens inserted on the throat of the calyx, Hamamelace;e. 



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

 Fruit separable into two dry caqjels. Flowers umbellate. IJMBELLiFERyE, 

 Fruit drupaceous, usually of more than two carpels. ARALiACEiE. 

 Fruit a 1 - 2-celled drupe. Flowers cymose or capitate. Cornace.*;, 



