IN EXTRA-TROPICAL COUNTRIES. 21 



Alnus glutinosa, Gaertner. 



The ordinary Alder. Throughout Europe and extra-tropical Asia, 

 up to 70 feet high ; well adapted for river-banks ; recommended by 

 Wessely for wet valleys in coast-sand ; wood soft and light, turning 

 red, furnishing one of the best charcoals for gunpowder ; it is also 

 durable under water, and adapted for turners' and joiners' work. 

 The wood is also well suited for pump-trees and other underground 

 work, as it will harden almost like stone. The tree is valuable for 

 the utilization of bog-land. A. incana (Willd.) extends to North 

 America ; it is of smaller size. The bark of several Alders is of 

 great medicinal value, and a decoction will give to cloth saturated 

 with lye an indelible orange colour (Porcher) ; it contains a pecu- 

 liar tannic principle. American Alder-extract has come into use 

 for tanning ; it renders skins particularly firm, mellow, and well- 

 coloured (Eaton). The bark contains 36 per cent, tannin (Mus- 

 pratt). A. Oregana, Nuttall, of California and Oregon, rises to a 

 height of 80 feet; its wood is extensively used for bent-work 

 (Meehan). A. Japonica and firma (Sieb. and Zuoo.), of Japan, 

 furnish wood there for carvers and turners and bark for black dye 

 (Dupont). 



Alnus Nepalensis, D. Don. 



Himalayas, between 3,000 and 9,000 feet. Beaches a height of 

 60 feet. With another Himalayan Alder, A. nitida (Endlicher), it 

 can be grown along streams for the sake of its wood. 



Aloe dichotoxna, Linne, fil. 



Damara and Namaqua-land. This species attains a height of 

 30 feet, and expands occasionally with its branches so far as to give 

 a circumference of 40 feet. The stem is remarkably smooth, with 

 a girth sometimes of 12 feet. It is a yellow flowering species. 

 A. Bainesii (Baker and Dyer) is almost as gigantic as the foregoing. 

 Both doubtless yield medical gum-resin like many others. A. Bar- 

 berse, which is closely related to A. Zeyheri, attains in Caffraria a 

 height of 40 feet, with a stem 16 feet in circumference at 3 feet 

 from the ground. 



Aloe ferox, Miller. 



South Africa. This species yields the best Cape aloe, as observed 

 by Dr. Pappe. The simply inspissated juice of the leaves of the 

 various species of the genus constitutes the Aloe drug. It is best 

 obtained by using neither heat nor pressure for extracting the sap. 

 By re-dissolving the aqueous part in cold water and reducing the 

 liquid through boiling to dryness the extract of aloes is prepared. 

 All species are highly valuable, and can be used, irrespective of their 

 medicinal importance, to beautify any rocky or otherwise arid spot. 



