APETALAE 



17 



177. (153.) .Ovules solitary in each ovary-cell 178 



Ovules 2 or more in each ovarj^-cell 183 



178. Ovules erect or ascending 17g 



Ovules pendulous or descending 180 



179. Leaves opposite or whorled. Perianth corolla-like. Ovary-cells and 



styles 2. Embryo curved 219. Rubiaceae. 



Leaves alternate. Perianth calyx-like. Embryo straight. 



137. Rhamnaceae. 



180. Perianth wanting in the male flowers. Stamens 4. Ovary almost com- 



pletely 2-celled. Seeds exalbuminous. Shrubs. Leaves stipulate. 



Corylus, 50. Betulaceae. 



Perianth present in all flowers. Seeds albuminous. Herbs or under- 



shrubs, rarely shrubs or trees, but then, as usually, leaves exstipu- 



late 181 



181. Flowers in umbels or heads, rarely in whorls, and then leaves stipulate. 



Perianth-segments 5, alternating with as many stamens. Ovary-cells 

 and styles 2. Seeds with horny albumen ; embryo small. 



186. Umbelliferae. 



Flowers sohtary or in axillary fascicles or in spikes. Leaves exstipulate. 



Perianth-segments 4, rarely 3 or 5. Seeds with fleshy or mealy albumen. 



Herbs or undershrubs ' . . 182 



182. Flowers hermaphrodite. Seeds with a curved embryo and mealy albumen. 



Leaves undivided. ....... Tetragonia, 72. Aizoaceae. 



Flowers unisexual or polygamous. Stamens 2, 4, or 8. Seeds with a 

 straight embryo and fleshy albumen. Leaves, at least the lower ones, 

 deeply divided Myriophyllum, 183. Halorrhagaceae. 



183. (177.) Ovules 2 in each ovary-cell. Styles 3 — 6. Perianth-segments 



more or less united. Flowers unisexual, spicate. Leaves stipulate. 



Trees or shrubs. ' 51. Fagaceae. 



Ovules numerous in each ovary-cell, rarely {Lecythidaceae) 2 — 6, but then 

 style I and flowers hermaphrodite. 184 



184. Perianth-segments obviously imited below. Seeds albuminous. Leaves 



without stipules 185 



Perianth-segments free or nearly so; Seeds exalbuminous. . . . 186 



185. Flowers unisexual, in terminal spikes racemes or panicles. Perianth 



regular. Fruit a berry. Embr}'o without cotyledons. Herbs. Leaves 



scale-Hke, not green Cytinus, 64. Rafflesiaceae. 



Flowers hermaphrodite, solitary or fascicled in the axils of the leaves. 

 Perianth irregular. Stamens adnate to the style. Fruit a capsule. 

 Embryo with 2 cotyledons. Leaves well developed, green. 



Aristolochia, 63. Aristolochiaceae. 



186. Flowers unisexual, in cymes. Perianth irregular. Stamens numerous. 



Styles 2 — 6, free or united at the base. Leaves stipulate. 



Begonia. 165. ' Begoniaceae. 



B 



