Hardy and Half-hardy Plants 



93 



R. chinensis (or glutinosa), 1-2 ft., is another species not so well known, 

 with dull-purple flowers striped with deeper tints. Both kinds are best 

 treated as half-hardy annuals or biennials, and are raised from seeds sown 

 in heat in spring. Another species is Henryi, 12-18 in. high, with yellow 

 and white flowers spotted with red. Hybrids have been raised between 

 chinensis and Henryi, and also between the latter and angulata. 



Rheum (RHUBARB). There are several species of Rhubarb distinguished 

 for their bold and ornamental foliage and huge plumes of blossom. They 

 all flourish in rich soil, but will do well in almost any garden soil that 

 is dug and manured. They are chiefly valuable for wilder parts of large 

 parks and gardens and by the sides of lakes, streams, &c., in the same 

 way as the Gunneras, which are often mistaken for them. The best 

 Rhubarbs are acuminatum, 3 ft.; australe, 6-10 ft.; Emodi, 6-10 ft.; 

 nobile, 3-5 ft.; officinale, 8-10 ft.; palmatum, 5-8 ft., of which there are 

 several varieties, including tanguticum,flore-roseo, and rubrifolium. These 

 are all natives of the Himalayas, Tibet, &c., and are easily raised from 

 seeds and by division of the rootstocks. 



Ricinus communis (CASTOR-OIL PLANT). An ornamental tropical plant 

 largely grown as a half-hardy annual for bedding-out purposes during the 

 summer months. The plants are valued for the large, lobed, and orna- 

 mental leaves, which assume tints of bronze and purple during the season, 

 and give a subtropical effect. The best varieties are borboniensis; Duchess 

 of Edinburgh; Cambodgensis, nearly black; Gibsoni, deep maroon; san- 

 guineus, with red stalks; and zarizibarensis, of which there are several 

 forms. 



Rochea (Crassula) falcata. This and R. perfoliata, both with fleshy 

 leaves covered with a glaucous bloom, are often used in carpet bedding 

 as dot plants over a carpeting of dwarf er plants. Raised from cuttings. 



Rock Garden and Alpine Plants. The trade in these plants is now 

 enormous. It would be impossible within the scope of this volume to 

 go into details of every species and variety grown for sale, although 

 the most important will be found described in their proper places. It 

 may be well, however, to indicate in a special group by themselves the 

 various genera from which the most noteworthy rock and alpine plants 

 are derived, as follows: 



