PAEOinrCHIACEiE — CRASSULACE^. 499 



shrabby plants, with opposite or alternate, sometimes setaceous and 

 clustered leaves, which are either exstipulate or have scarious stipules. 

 Found in barren places in various parts of Europe, Asia, and North 

 America. A slight degree of astringency pervades this order, and is 

 the only sensible property that it is known to possess. This order 

 is allied to Oaryophyllaceee in many respects. It is placed by some 

 among the Monochlamydeous orders, as being allied to Chenopodiacese. 

 The order has been divided into two sections : — 1. lUecebrese, with 

 the embryo lying on one side of the albumen, and stipulate leaves. 

 2. Scleranthese, with a peripherical embryo and exstipulate, leaves. 

 There are 30 known genera, and nearly 120 species. Examples — 

 Paronychia, lUecebrum, Polycarpon, Oorrigiola, Scleranthus. 



Order 83. — CEASSULACE.ffli, the Houseleek or Stonecrop Family 

 (figs. 634, 635, p. 365). {Poly-pet. Perigyn.) Sepals 3-20, more or 

 less united at the base (fig. 282 c c, p. 191). Petals equal to the 

 sepals in number, inserted in the bottom of the calyx (fig. 282 pp, 

 p. 191), either distinct or cohering in a gamopetalous corolla. Stamens 

 inserted with the petals, either equal to them in number, and alternate 

 with them (fig. 282 e e, p. 191), 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 

 longitudinally or transversely. Abortive stamens or scales (sometimes 

 obsolete), at the base of each carpel (fig. 282 a a, p. 191). Carpels 

 equal in number to the petals and opposite to them, 1 -celled (fig. 

 282 0, p. 191), sometimes consolidated ; styles several or combined ; 

 stigmas pointed or 4-cornered ; ovules 00, or definite, anatropal. Fruit 

 consisting of several follicles, dehiscing by the ventral suture, some- 

 times by the dorsal suture. Seeds variable in number; embryo straight 

 in the midst of fleshy albumen ; radicle pointing to the hrlum. — Her- 

 baceous plants or shrubs, often succulent, with simple, entire, or 

 pinnatifid, exstipulate leaves. They are found in the driest situations, 

 as on rocks, walls, and sandy plains, in various parts of the world. 

 Some of them are acrid, as Sedwm acn, Biting Stonecrop ; others are 

 refrigerant, from the presence of an acid, such as malic- acid. Sem- 

 pervivum tectorum is commonly known as the Houseleek. The fisher- 

 men of Madeira rub their nets with the fresh leaves of the Sempervivum 

 fflutinosum, by which the nets are rendered as durable as if tanned, 

 provided they are steeped in some alkaline liquor. Bryophyllum caly- 

 cinum is remarkable for the property of producing germinating buds 

 at the edges of its leaves (p. 118). In the leaves of some of the 

 species, as Cmssula profvsa, 0. laetea, and C. marginata, there are 

 two kinds of stomata ; one kind being of the ordinary size, and sqat- 

 tered over the leaves, the other being very minute, and raised on orbi- 

 cular slightly convex punctiform disks, arranged in a row within the 

 margin of the leaf. These disks consist of dense cellular tissue which 



