856 THE BOOK OF GARDEXIXG. 



beautiful olive-green. C. Kicsteriana, a dwarf species, produces a 

 considerable amount of suckers, which may be utilised for propa- 

 gation ; its pinnate and spreading leaves are 2ft. to 4ft. long, 

 and have semi-lunate pinnae. C. mexicana is a decorative species, 

 having a stout stem with armed petioles, bearing some beautiful 

 leaves 4ft. in length, with dark green pinnae. C. Miqueliana is 

 another decorative species, with a slender stem and elegant 

 pinnate, spreading leaves ; the pinnae are of coriaceous habit, 6in. 

 to i2in. in length, and dark green. 



CvcAS. — A well-known genus, comprising stove and green- 

 house plants, some of which may be used with success in sub- 

 tropical gardening. Cycas have cylindrical stems, mostly 

 unbranched, and terminated by a beautiful crown of pinnate 

 leaves. For culture and propagation see under " Ceratozamia." 

 C. ch'cinalis, one of the prettiest species of the genus, produces 

 a stout and cylindrical stem, rather slender in the case of 

 male specimens : the leaves are 6ft. to 12ft. long, and have 

 shiny green pinnae, often reaching i2in. C. media is rather 

 tall, with a stout, tall, cylindrical stem bearing elliptic-lanceolate 

 leaves, with a considerable number of pinnae, which are transformed 

 into spines at the base of the leaves ; it deserves general 

 cultiwition. C. N'oi-manbyana somewhat resembles C. circinalis ; 

 its oblong-ovate leaves have a quantity of pinnje, and the 

 compressed petioles are covered at their base witth furfuraceous 

 down. C. revoliita is one of the most robust and oldest 

 species in cultivation, and is useful for sub-tropical gardening ; 

 in its young state the stem is simple, but with age it becomes 

 branched, and is terminated by a graceful crown of leaves. 

 C. Riu?]iiniana is ^"ery well known, and is of beautiful habit ; 

 its moderately stout stem bears erect spreading leaves, with 

 rich shiny green pinnae. C. Rumphii is another handsome 

 slender species, with petioles protected by two rows of small 

 spines ; the leaves are 4ft. to 6ft. long, and have linear- 

 lanceolate pale green pinnae. 



DiooN. — A very small genus, only one species {D. edule) being 

 known in cultivation. It is valuable for the economical 

 properties of its large fruits. The stem is of moderate size, and 

 supports a fine crown of glaucous green pinnate leaves, 3ft. 

 to 6ft. long, and having their base covered with hairy matter. 

 This species is an extremely ornamental plant, which requires a 

 good sandy loam. During the summer it may be removed into 

 a greenhouse, but requires stove treatment throughout the winter. 

 Increased by seeds only. 



ExcEPHALARTOS. — One of the lars^est ^enera of the order, and 

 belonging to the South African flora. It is composed of beautiful 

 plants for conservatories or greenhouses, and some of the species 

 may be used for sub-tropical gardening during the summer months. 



