540 SYSTEMATIC BOTANY. 



metrical. Calyx inferior, or generally more or less superior, 4 

 — 5-parted. Stamens perigynous or hypogynous. Ovary supe- 

 rior, or more or less inferior, composed of 2 carpels united at the 

 base, and diverging at the apex ; styles distinct, equal in number 

 to the carpels. Fruit capsular, 1 — 2 -celled. Seeds numerous, 

 small, with fleshy albumen. 



Distribution, ^c. — They are exclusively natives of the northern 

 parts of the world, where they chiefly inhabit mountainous dis- 

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

 level of the sea. Examples: — Vahlia, Saxifraga, Chrysosple- 

 nium, Heuchera. There are 19 genera, and 310 species. 



Properties and Uses. —The plants ot the order are all more or 

 less astringent. This is remarkably the case with 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. Hydrangeace;e. — The Hydrangea Order 

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

 of Saxifragaceas, Avith which it agrees in many important parti- 

 culars ; but it diffei's 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 floAvers ; and in 

 having frequently more than 2 carpels with a corresponding in- 

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



Distribution, Sfc. — Natives chiefly of the temperate regions of 

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

 of China and Japan. Examples : — Hydrangea, Platycrater, 

 Bauera. There are 9 genera, and 45 species. 



Properties and Uses. — Unimportant. The leaves of Hydrangea 

 Thunbergii are used in Japan as tea, and this tea is so highly 

 valued by the Japanese, that they call it Ama-tsjd or the Tea of 

 Heaven. The Hydrangeas are familiar cultivated plants. The 

 root of H arborescens, under the name of Leven Bark or Wild 

 Hydrangea, is largely employed in some parts of North America 

 in calculous complaints. 



Natural Order 87. Hensloviace^.— The Henslovia Order. — 

 Diagnosis. — This is a small order of tropical plants containing 

 but 1 genus, and 3 or 4 species, which is considered by Lindley 

 to be nearly allied to Hydrangeaceie. The chief differences 

 being in their tree-like habit; in their styles being united into a 

 cylinder, and in the total absence of albumen. Example : — 

 Henslovia, Their properties and uses are unknown. 



Natural Order 88. Cunoniace^. — The Cunonia Order. — 

 Diagnosis. — Nearly allied to Saxifragaceai, but differing from 

 them in lieing trees or shrubs, with opposite leaves, and large 

 intcr[)cti()lar stii)ulcs. The latter character will also distinguish 

 them readily from Hydrangeacea?, which are exstipulate. 



Distribution, §-c. — Natives of South America, the Cape, the 



