Leaves scale-like, not green, rarely well-developed and green, but then inner perianth-segments much smaller than the outer or wanting, anthers provided with an enlarged connective and opening transversely, and stigmas 3, short and thick. =43. Burmanniaceae.= 45. Ovary incompletely 6-15-celled with 6-15 stigmas, more rarely completely 1-celled with 3 stigmas. Perianth consisting of calyx and corolla, more rarely only of 3 petal-like segments. Water-plants with submerged or floating leaves. =14. Hydrocharitaceae.= Ovary 3-celled, rarely 1-celled, but then stigmas 6. Perianth usually of 6 petaloid segments. Land-plants. 46 46. Ovary 1-celled. Style umbrella-shaped, 6-lobed. _Tacca_, =36. Taccaceae=. Ovary 3-celled. 47 47. Ovules in each ovary-cell 2, one above the other. Flowers unisexual, regular. Stem climbing. =37. Dioscoreaceae.= Ovules in each ovary-cell 1, 2 side by side, or more. Flowers hermaphrodite, rarely unisexual but irregular. 48 48. Perianth distinctly differentiated into calyx and corolla. Leaves toothed. Inflorescence spadix-like. _Ananas_, =27. Bromeliaceae=. Perianth more or less corolla-like. 49 49. Flowers distinctly irregular, in fascicles usually arranged in spikes or racemes. Stamens 5, rarely 6. Seeds with more or less mealy albumen. Leaves with pinnate nervation. Tall plants. =39. Musaceae.= Flowers regular or nearly so. Stamens 6 or more. Seeds with fleshy or cartilaginous albumen. Leaves nearly always with longitudinal nervation. 50 50. Flowers solitary, terminal. No bulb or tuber; usually a short woody trunk. Placentas much projecting, thickened, shield-shaped. _Barbacenia_, =35. Velloziaceae=. Flowers in umbels, spikes, racemes, or panicles, more rarely solitary, but then underground stem a bulb or a tuber. Placentas not much projecting and thickened. 51 51. Ovary half-inferior, with 2 basal ovules in each cell. Anthers opening at the apex. Seeds with a large embryo adjoining the albumen. Flowers in racemes or panicles. _Cyanastrum_, =30. Cyanastraceae=. Ovary inferior, rarely half-inferior, but then with more than two ovules in each cell. Seeds with a small embryo enclosed in the albumen. =34. Amaryllidaceae.= 52. (5.) Perianth wanting or simple or consisting of a calyx and a choripetalous corolla; petals, if present, free, more rarely cohering at the apex or in the middle, but free at the base. [Subclass ARCHICHLAMYDEAE.] 53 Perianth consisting of a calyx and a sympetalous corolla; petals more or less united, at least at the base. [Subclass METACHLAMYDEAE or SYMPETALAE.] 551 53. Perianth wanting or simple, that is, consisting of similar segments, more rarely of 2-7 somewhat dissimilar ones without a distinct differentiation into sepals and petals. [APETALAE.] 54 Perianth differentiated into calyx and corolla, more rarely consisting of 8 or more slightly dissimilar segments not distinctly separated into sepals and petals. [CHORIPETALAE.] 188