NATUBAL OEDEHS. 49 



XV. Flax family. Leaves entire. Petals convolute, distinct. Stamens 

 definite. Capsule separating into carpels without leacmg a central axis. 



XVI. Mallow family. Sepals valvate. Petals convolute, adhering at the 

 base to the starainal tube.- Stamens indefinite, monadelphous, with one- 

 celled anthers. 



XVII. Lime family. Trees. Sepals valvate. Petals free. Stamens in- 

 definite. 



XVIII. Geranium family. Leaves opposite, toothed or divided. Petals 

 convolute. Stamens definite. Capsule with several cells and lobes round a 

 persistent central axis. 



XIX. Balsam genus or family. Perianth, very irregular. Stamens 5, the 

 anthers cohering in a ring. Capsule opening elastically. 



XX. Milkwort family. Perianth very irregular. Stamens 8, in two parcels ; 

 petals united with them at the base. 



XXI. Maple genus or tribe (of Sapindacem) . Trees. Leaves opposite. 

 Stamens definite, but seldom isomerous. Fruit separating into 2 (rarely 3) 

 ■winged nuts. 



Subclass 2. Caltcifloees. — Petals usually distinct, and stamens peri- 

 gynous or epigynous. 



* Stamens and petals mostly perigynous ("except in the (Enothera, Gourd, 

 and B,lhes families) . 



XXII. Celastrus family. Shrubs or trees, with small regular green flowers. 

 Stamens alternating with the petals, on a disk lining the base of the calyx. 



XXI II. Buckthorn family. As in the Celastrus famUy, but the stamens 

 are opposite the small concave or scale-like petals. 



XXtV. Peaflower tribe (of the Leguminous family). Flowers very irregular, 

 papilionaceoiis. Stamens 10, all, or 9 of them, combined. Ovary of one 

 carpel. 



XXV. Eose family. Flowers regular. Stamens indefinite. Ovary (at 

 least when young) apocarpous. 



XXVI. Oenothera family. Perianth in twos or fours. Stamens definite. 

 Ovary inferior. One style. 



XXVII. Lythrum family. Stamens usually definite, inserted with the 

 petals at the top of the calyx-tube. Ovary syncarpous within the base of 

 the tube. One style. Lower leaves opposite. 



XXVIII. Gourd family. Climbers with tendrils. Flowers unisexual. 

 Ovary inferior. 



XXIX. Purslane family. As in the Pink family, but only two sepals, 

 and 5 or more perigynous petals and stamens. 



XXX. Paronychia family. Herbs. Leaves entire, usually opposite. Flowers 

 regular. Stamens definite (all as in the Pink family). Petals very small, 

 or none. Ovary free, with one ovule. 



XXXI. Crassula family. Leaves succulent. Sepals, petals, stamens of one 

 or two rows, and free carpels, all isomerous. 



XXXII.' Kibes genus or family. Shrubs. Flowers regular. Stamens 

 definite. Ovary inferior. Placentas pai-ietal. One style. 



XX.KIII. Saxifrage family. Flowers regular. Stamens definite. Ovai*y 

 syncarpous at the base, but a separatj style for each carpel. 



** Petals and stamens epigynous fround an epigynotis disJcJ. 

 XXXIV. Umbellate family. Leaves alternate. Fruit dry, separating 

 from the axis into seed-like carpels. 



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