278. Sepals 3. Petals 3 or 6. Shrubs or trees. Leaves alternate, undivided, exstipulate. 279 Sepals 4 or 5, rarely 2. Petals 3-5. 280 279. Sepals valvate in bud. Stamens numerous. Anthers opening outwards. Ovary many-celled. Styles numerous. =81. Anonaceae.= Sepals imbricate or open in bud. Stamens 3. Anthers opening laterally. Ovary 2-9-celled. Style 2-9-cleft. Flowers unisexual or polygamous. =125. Empetraceae.= 280. Sepals valvate in bud, 5. Petals with contorted aestivation. Filaments united. Stigmas several. Leaves simple, stipulate. 281 Sepals imbricate in bud, rarely valvate, but then only 2. Leaves exstipulate. 282 281. Anthers 1-celled. Fertile stamens numerous. Ovary 3-or more-celled. Seeds albuminous. =142. Malvaceae.= Anthers 2-celled. Fertile stamens 5, rarely more, but then ovary 2-celled and seeds exalbuminous. =144. Sterculiaceae.= 282. Stamens numerous. Leaves opposite, undivided. Shrubs or trees. =149. Guttiferae.= Stamens 2-10. Stigmas 1-2. Leaves alternate. 283 283. Leaves pinnate. Shrubs or trees. Stigma 1. =118. Meliaceae.= Leaves simple. Herbs or undershrubs, rarely shrubs. Embryo curved. 284 284. Sepals 4. Petals 4. Stamens 2-6. Glands present between the stamens. =88. Cruciferae.= Sepals 5. Petals 3-5. Stamens 5-10, united at the base. _Limeum_, =72. Aizoaceae=. 285. (277.) Flowers irregular. Petals 4-5. Stamens 10-20. Ovary 2-celled. Style basal. Stigma 1. _Parinarium_, =103. Rosaceae=. Flowers regular. Petals 4-8. Stamens 4-8. Style terminal or nearly so. 286 286. Petals, stamens, and carpels 8 each. _Dirachma_, =107. Geraniaceae=. Petals 4-5. Stamens 4-5. Carpels 2-5. 287 287. Calyx with valvate aestivation. Stamens opposite the petals. Style 1, with a more or less deeply divided stigma, or several styles. =137. Rhamnaceae.= Calyx with imbricate or open aestivation. Stamens alternate with the petals. Style 1, with an entire or lobed stigma. =129. Celastraceae.= 288. (274.) Flowers unisexual. 289 Flowers hermaphrodite or polygamous. 293 289. Leaves simple. 290 Leaves compound. Shrubs or trees. 293 290. Sepals 2-3, united below, valvate in bud. Petals 5, with contorted aestivation. Stamens numerous. Ovary 2-celled. Style wanting; stigma lobed. Shrubs or trees. _Carpodiptera_, =141. Tiliaceae=. Sepals, at least in the female flowers, 4-6, sometimes almost wholly united. 291 291. Ovary slightly sunk in the receptacle, 2-celled. Styles 2. Stamens 5. Anthers opening by valves. Sepals and petals valvate in bud. Shrubs. _Trichocladus_, =101. Hamamelidaceae=. Ovary wholly superior, usually 3-celled. Styles usually 3. Anthers opening by longitudinal slits. 292 292. Ovules straight. Stigmas sessile or nearly so. Stamens 10. Calyx-limb nearly entire. Fruit drupaceous. _Panda_, =106. Pandaceae=. Ovules inverted. =122. Euphorbiaceae.= 293. Leaves stipulate. Ovary surrounded by scales. Fruit capsular. Spiny shrubs. _Neoluederitzia_, =113. Zygophyllaceae=.