Flowers hermaphrodite, rarely unisexual or polygamous, but then irregular. Stamens as many as the divisions of the corolla. Seeds albuminous. Leaves entire, toothed, or lobed. 766 766. Corolla with contorted aestivation. Ovary 2-celled. Style simple, stigmatose beneath the thickened apex. =200. Apocynaceae.= Corolla with imbricate (not contorted) or valvate aestivation. Style stigmatose at the apex or between the apical lobes. 767 767. Corolla imbricate in bud, regular. Ovary 2-celled, with 2-4 ovules in each cell. Style simple with 2 stigmas or 2-parted. Shrubs or undershrubs. =100. Bruniaceae.= Corolla valvate in bud, rarely imbricate, but then irregular or ovules numerous. Style simple. 768 768. Style with hairs or glands in its upper part, rarely without, and then corolla irregular or imbricate in bud. Stigma more or less deeply divided, at least after the period of flowering. =224. Campanulaceae.= Style without hairs or glands. Stigma entire, capitate. Ovary 3-4-celled with numerous ovules. Anthers free. Corolla regular, 5-partite, valvate in bud. Undershrubs. _Berenice_, =96. Saxifragaceae=. 769. (758.) Stamens 8-10. Seeds with a straight embryo and abundant fleshy albumen. _Vaccinium_, =189. Ericaceae=. Stamens numerous. 770 770. Corolla of numerous petals united at the base. Seeds with a curved embryo and mealy albumen. Herbs or undershrubs. _Mesembryanthemum_, =72. Aizoaceae=. Corolla of 3-6 petals. Shrubs or trees. 771 771. Petals united at the base, imbricate in bud. Filaments united at the base. Ovary inferior. Seeds exalbuminous. =176. Lecythidaceae.= Petals united into a hood throughout their whole length, sometimes finally separating. Filaments free or nearly so. 772 772. Ovary half-inferior. Seeds albuminous. _Rhaptopetalum_, =145. Scytopetalaceae=. Ovary inferior. Seeds exalbuminous. Leaves gland-dotted. =180. Myrtaceae.= KEY TO THE GENERA EMBRYOPHYTA SIPHONOGAMA (PHANEROGAMAE) SUBDIVISION GYMNOSPERMAE CLASS I. CYCADALES FAMILY 1. CYCADACEAE Stem simple, rarely branched at the top, woody, with mucilagineous juice. Leaves pinnate or pinnatisect, forming a tuft at the top of the stem and intermingled with scales. Flowers solitary, terminal, in the shape of a cone (but sometimes overtopped by the continued growth of the stem), dioecious, without a perianth. Stamens bearing many pollen-sacs on their lower side. Ovules 2-8 to each carpel, straight, with a single coat. Seeds drupe-like, albuminous. Embryo with two more or less united cotyledons.--Genera 3, species 25. Tropical and South Africa. (Plate 1.)