[*] 4. Calyx imbricate; stamens as many or twice as many as the petals or often indefinite; ovary compound, 1-celled with parietal placentæ or several-celled with the placentæ united in the axis; embryo straight or slightly curved; albumen none or scanty.
17. [Elatinaceæ] ([p. 91]). Small marsh annuals, with opposite leaves, membranous stipules, minute axillary flowers, few stamens, and pod 2–5-celled.
18. [Hypericaceæ] ([p. 92]). Herbs or shrubs, with opposite entire dotted leaves and no stipules. Flowers cymose or panicled. Stamens few or many, usually in 3 or more clusters. Pod 1-celled or 3–5-celled.
19. [Ternstrœmiaceæ] ([p. 95]). Trees or shrubs, with alternate leaves and no stipules. Flowers large, axillary, solitary. Stamens numerous, more or less united together and with the base of the petals. Pod 3–5-celled.
[*] 5. Calyx valvate; stamens numerous, usually more or less united together and with the base of the petals; ovary 3–many-celled with the placentæ united in the axis (becoming 1-celled and 1-seeded in Tilia).
20. [Malvaceæ] ([p. 96]). Stamens monadelphous; anthers 1-celled. Calyx persistent. Seeds kidney-shaped, with curved embryo and little albumen. Herbs or shrubs, with alternate palmately veined stipular leaves.
21. [Tiliaceæ] ([p. 101]). Stamens polyadelphous or nearly distinct; anthers 2-celled. Calyx deciduous. Embryo nearly straight. Trees, with alternate leaves and deciduous stipules.
B. DISCIFLORÆ. Stamens as many as the petals or twice as many or fewer, inserted upon or at the outer or inner base of a more or less tumid hypogynous or perigynous disk, which is cushion-like or annular or divided into glands, sometimes obscure or minute (or none in Linum, Ilex, some Geraniaceæ and Polygala); ovary superior (or half-inferior in some Rhamnaceæ); sepals more usually distinct. Petals wanting in some Rutaceæ, Rhamnaceæ, and Sapindaceæ.
[*] 1. Ovules (mostly 1 or 2 in each cell) pendulous, with the rhaphe toward the axis of the ovary; disk often reduced to glands alternate with the petals or none; ovary often lobed or the carpels nearly distinct.
22. [Linaceæ] ([p. 101]). Flowers regular, usually 5-merous. Capsule not lobed, mostly 5-valved, spuriously 10-celled, 10-seeded. Stamens united at base. Disk none or 5 minute glands. Herbs, with entire alternate or opposite leaves; stipules gland-like or none.