423. Leaves simple. Flowers with an epicalyx. Filaments united to the apex or nearly so. Pollen-grains spiny. =142. Malvaceae.= Leaves palmately compound. Flowers without an epicalyx. Filaments united below. Pollen-grains smooth or nearly so. Trees. =143. Bombacaceae.= 424. Filaments more or less united. Staminodes present. =144. Sterculiaceae.= Filaments free, rarely shortly united at the base, but then staminodes absent. =141. Tiliaceae.= 425. (418.) Calyx and corolla with contorted aestivation. Petals 5-6. Ovary sessile or nearly so. Seeds albuminous. Leaves undivided. 426 Calyx and corolla with imbricate, not contorted aestivation. 427 426. Disc present. Ovules inverted. =140. Chlaenaceae.= Disc absent. Ovules usually straight. =154. Cistaceae.= 427. Ovary sessile, 2-3-celled. Style awl-shaped. Ovules ascending. Seeds with copious albumen. Flowers regular. Leaves undivided. _Sphaerosepalum_, =156. Cochlospermaceae=. Ovary stalked. Seeds without albumen. =87. Capparidaceae.= 428. (417.) Leaves all radical, floating, peltate. Petals numerous. Ovary 6-or more-celled. Stigma sessile. Seeds albuminous; embryo straight. _Nuphar_, =76. Nymphaeaceae=. Leaves cauline and radical or all cauline, not floating. Petals 4-5. 429 429. Leaves opposite. Calyx with valvate, open, or imbricate, not contorted aestivation. Filaments usually united in several bundles. Seeds exalbuminous. =149. Guttiferae.= Leaves alternate, more rarely (Cistaceae) opposite, but then calyx and corolla with contorted aestivation, filaments free, and seeds albuminous. 430 430. Leaves compound, with 1-3 leaflets, translucently dotted. Sepals united below. Ovary sessile, 5-or more-celled. Seeds exalbuminous. =115. Rutaceae.= Leaves simple, undivided, not dotted, rarely digitate or dotted, but then ovary stalked. 431 431. Ovary stalked. Stigma usually sessile. Disc usually present. Seeds exalbuminous. =87. Capparidaceae.= Ovary sessile. Disc not distinctly developed. Flowers regular. 432 432. Sepals and petals with contorted aestivation. Ovules usually straight. Seeds albuminous. =154. Cistaceae.= Sepals and petals 5, with imbricate, not contorted aestivation. Ovules inverted or incurved. Trees or shrubs. =148. Theaceae.= 433. (416.) Calyx with valvate, closed, or open aestivation. 434 Calyx with imbricate or contorted aestivation. Leaves undivided. 438 434. Corolla with valvate, calyx with open aestivation. Ovary 3-8-celled. Seeds albuminous. Leaves alternate, undivided. Trees or shrubs. =145. Scytopetalaceae.= Corolla with imbricate or open aestivation; in the latter case calyx valvate. Seeds exalbuminous, rarely with scanty albumen, but then leaves digitate. 435 435. Anthers opening by a single slit. Filaments united. Ovary 5-10-celled, slightly sunk in the receptacle. Petals 5, with contorted aestivation. Seeds albuminous. Leaves digitate, stipulate. Trees. =143. Bombacaceae.=