163 
genus of this order, exhibits the singular anomaly of placentae being opposite 
the lobes of the stigma, an unilocular ovary, the shell of which consists of two 
distinct plates connected by an interv'ening loose substance, and a peculiar de- 
velopement of an hypogynous disk, which assumes the form of 5 fringed scales, 
alternate wdth the stamens, and of a highly curious structure. Drummondia 
has the stamens equal in number to the petals and opposite them, thus in- 
dicating some analogy with the monopetalous Primulacese. 
Geography. Little elegant herbaceous plants, usually w*ith white flowers, 
csespitose leaves, and glandular stems : some of the species have yellow 
flowers, others have red, but none blue. They are natives of mountainous 
tracts in Europe and the northern parts of the world, frequently forming the 
chief beauty of that rich turf which is found near the snow in high Alpine 
stations. Some grow on rocks and old walls, and in hedge-rows, or near ri- 
vulets, or in groves. 
Properties. According to De Candolle, the whole order is more or less 
astringent. The root of Heuchera americana is a powerful astringent, whence 
it is called in North America Alum root. Barton. 2. 162. Otherwise the 
species possess no known properties ; for the old idea of their being li- 
thontriptic appears to have been derived from their name rather than their 
virtues. 
GENERA. 
§ 1. Hydrangea, DC. 
Hydrangea, L. 
Hortensia, Juss. 
Primula, Lour. 
Comidia, R. et P. 
Sar costyles, Presl. 
Cianitis, Reinw. 
Adamia, Wall. 
Broussaisia, Gaudch. 
§ 2. Saxifrages, DC. 
Saxifraga, L. 
Porphynon, Tausch. 
Antiphyllum, Haw. 
Calliphyllum, Gaud. 
Dactyloides, Tausch. 
Muscaria, Haw. 
Triplinervium,GdLVid.. 
Micranthes, Tausch. 
Dermasea, Haw. 
Arahidia, Tausch. 
Spatularia, Haw. 
Micropetalum, 
Tausch. 
Cotylea, Haw. 
Boykinia, Nutt. 
Leiogyne, Don. 
Aizoonia, Tausch. 
Chondrosea, Haw. 
Cotyledon, Gaud. 
Trigonophyllum, 
Gaud. 
Porophyllum, Gaud. 
Bergenia, Monch. 
Geryonia, Schr. 
Megasea, Haw. 
Eropheron, Tausch. 
Robertsonia, Haw. 
Hydatica, Tausch. 
Diptera, Borkhs. 
Aulaxis, Haw. 
Hirculus, Tausch. 
Kingstonia, Gray. 
Leptarrhena, R. Br. 
Chrysosplenium, L. 
Cryptopetalum, 
H. et A. 
Mitella, Toum. 
Tellima, R. Br. 
Lithophragma, Nutt. 
Drummondia, DC. 
Tiarella, L. 
Astilbe, Hamilt. 
Heuchera, L. 
Donatia, Forst. 
Lepuropetalum, 
Elliott. 
Vahlia, Thunb. 
Bistella, Caill. 
Oresitrophe, Bge. 
Hoteia, Morr. 
Oreanthus, Raf. 
Zahlbruckneria, Rchb . 
Pamassia, L. 
Alliance III. CRASSALES. 
Essential Character. — Carpels several, quite distinct, continuous with the styles, which 
are little more than the tapering ends of the ovaries. Seeds wery numerous with albumen. 
These characters and the succulent habit are so distinctive, that nothing 
further need be said concerning the aUiance. 
Order CXVII. CRASSULACE^E. The House-leek Tribe. 
Sempervivs, Juss. Gen. 207. (1789). — Succulents, Vent. Tabl. 3.271. (1799). — Cras- 
suLS, Juss. Diet, des Sc. Nat. 11. 369. (1818). — Crassulaces, DC. Bull. Philom. 
n. 49. p. 1. (1801) ; FI. Fr. ed. 3. v. 4. p. 271. (1805) ; Memoire (1828) ; Prodr. 
3. 381. (1828) ; Lindl. Synops. 63. (1829). — Sedes, Spreng. 
Essential Character — Sepals from 3 to 20, more or less united at the base. Petals 
inserted in the bottom of the calyx, either distinct or cohering in a monopetalous corolla. 
