BOTANY. 151 
shrubby succulent plants, with opposite or alternate simple leaves. They 
are found in warm regions chiefly. The greater part of them grow at the 
Cape of Good Hope. The order has been divided into three sections: 1. 
Mesembryex, numerous conspicuous petals, plurilocular capsule, with 
stellate dehiscence. 2. Tetragoniee, petals 0, fruit woody and indehiscent. 
3. Sesuvex, petals 0, capsule with circumscissile dehiscence. There are 
sixteen known genera, and 440 species. Examples: Mesembryanthemum, 
Tetragonia, Aizoon, Sesuvium. No species of this order are native to 
North America. Mesembryanthemum crystallinum is often cultivated in 
green-houses under the name of ice-plant, so called from the peculiar 
appearance of the leaves. 
Mesembryanthemum rubrocinctum (pl. 69, fig. 5). 
Orper 133. CrassuLtace®, the House-leek Family. Sepals three to 
twenty, more or less united at the base. Petals equal to the sepals in 
number, inserted in the bottom of the calyx, either distinct, or cohering in 
a gamopetalous corolla. Stamens inserted with the petals, either equal to 
them in number, and alternate with them, or twice as many, those opposite 
the petals being shortest; sometimes one or two rows of abortive stamens ; 
filaments distinct or united, subulate; anthers bilocular, dehiscing longi- 
tudinally or transversely. Abortive stamens or scales (sometimes obsolete), 
at the base of each carpel. Carpels equal in number to the petals and 
opposite to them, one-celled, sometimes consolidated; styles several or 
combined ; stigmas pointed or four-cornered; ovules 00, or definite, 
anatropal. Fruit consisting of several follicles, dehiscing by the ventral 
suture, sometimes by the dorsal suture. Seeds variable in number; embryo 
straight, in the midst of fleshy albumen; radicle pointing to the hilum. 
Herbaceous plants or shrubs, often succulent, with simple, entire, or pinna- 
tifid, exstipulate leaves. They are found in the driest situations, as on 
rocks, walls, and sandy plains, in various parts of the world. 
Tribe 1. Crassule@. Carpels (follicles) distinct ; dehiscent by the inner 
suture. Szub-tribe 1. [sostemones. Stamens equal in number to the petals. 
Section a. Eucrassulee. Examples: *Tillea, Crassula. Section 0. 
Rochee. Example: Rochea. Sub-tribe 2. Diplostemones. Stamens twice 
as many as the petals. Section a. Umbilicee. Example: *Echeveria. 
Section b. Sedeew. Examples: *Sedum, Sempervirum. 
Tribe 2. Diamorphee. Carpels more or less united, dehiscent by the 
separation of the dorsal portion. Examples: *Diamorpha, *Penthorum. 
Some of the plants of this order are acrid, as Sedum acre ; Sempervivum 
tectorum is known as the House-leek. There are five genera, with twenty 
species, in North America. 
Sedum acre, Stone crop, Europe (pil. 69, fig. 1); a, the plant; }, a 
flower ; c, the five carpels; d, one of the same; e, f, seeds; g, leaves. 
Orper 134. SurtaAnace&. Sepals five, persistent; estivation twisted, 
imbricated. Petals five, alternate with the sepals, distinct, inserted into the 
bottom of the calyx. Stamens five, alternate with the petals, sometimes with 
five alternating ones, that are occasionally abortive, all inserted with the 
petals; filaments persistent, distinct, subulate from a broad base, hairy 
151 
