CAXYCIFLORJE. 



535 



tricts, and sometimes grow as high as 16,000 feet above the 

 level of the sea. Exayyiplcs of the Genera : Saxifraga, Chrysosple- 

 nium, Heuchera. There are 312 species. 



929. Fig. 930. 



Fig. 931. 



Fig. 929. Saxifraga tridactxjUtes. The leaves are trifld and wedge-sliaped, 



and the flowers arranged in a raremose cyme. Fig. 930. Vertical 



section of the flower. Fig. 991. Vertical section of the seed. 



Trcyperties and Uses. — The plants of the order are all more or 

 less astringent. This is remarkably the case -vnth the root of 

 Heuchera americana, -which is much used for its astringent pro- 

 perties in the United States under the name of Alum-root. 



Natural Order 86. Hydrangeaceje. — The Hydrangea Order. 

 — Diagnosis. — This order is freqiieutly regarded as a sub-order 

 of Saxifragaceae, with whicli it agrees in many important parti- 

 culars ; but it differs in the plants belonging to it being of a 

 shrubby nature ; in their having opposite leaves, which are always 

 exstipulate ; in their tendency to a polygamous structure as ex- 

 hibited in the possession of radiant staminal flowers ; and in 

 having frequently more than 2 carpels with a corresponding in- 

 crease in the number of styles and cells to the ovary. 



Bistrihution, <^'C. — Natives chiefly of the temperate regions of 

 Asia and America. About one-half of the species are natives 

 of China and Japan. Examples of the Genera: — Hydrangea, 

 Bauera. There are 45 species. 



