30 OACIACEOnS PLANTS. 



fectly formed mamillse, resembling aloid leaves 4 or 5 inches long, glaucong 

 green, succulent, triangular, truncated at the apex, and there bearing six or 

 seven long chafEy, or almost horny linear or subulate flexuose scales, of which 

 ihe centre one is about as long as the mamillse, and the others form a whorl 

 round the centre, are about 2 or 3 inches long, spreading, triangular. These 

 appear to be after a time deciduous, for the lower withered mamilla; are 

 destitute of them." In the further description of the flower the position is 

 said to be " from the axil of a mamilla," but in the " Genera Plantarum " 

 this has been corrected. The flowers are large, of a rich clear yellow tint, 

 and are usually solitary, though in some cases two are borne on one plant at 

 the same time. 



The species is a native of Mexico, having been found near the Eio del 

 Monte, and introduced to the Royal Gardens, Kew, in 1847. Xiike the 

 Pelecyphora, Mr. Corderoy has been very successful with this plant, and the 

 engraving represents one from a photograph of eight plants, several being in 

 flower, which he had taken some time since. 



ECHINOCACTUS, Zinli and Otto. 

 (The Hedgehog Cactus.) 

 The Hedgehog Cactus genus is one of the largest in the whole 

 family, and the two hundred species comprised in it include some of the 

 most handsome and curious forms in this portion of the vegetable world. 

 They are not so remarkable for beauty and symmetry of structure as the 

 Mamillarias, but the flowers are usually large, brightly coloured, the 

 tints most predominating being yellow, rose, and purple, while many are 

 pure white. The flowers also in numerous species attain a considerable 

 size, almost rivalling some of the Cereus ; and as they frequently open 

 for several days in succession they have not the defect of fugaciousness 

 80 common in other members of the family. The strangest character 

 connected with the Hedgehog Cactus is, however, the enormous size 

 which some of them attain. It is true they do not grow to so great a 

 height as the Cereus, for few, even of the largest, exceed 4 or 5 feet in 

 height, but they occasionally become excessively bulky, as in E. Visnaga, 

 sometimes weighing as much as a ton, though there is every gradation 

 from that to species as diminutive as the Mamillarias. The majority of 

 globular stems like the Melocactus, with more or less strongly marked 

 ridges from the summit to the base, usually slightly spiral, though fre- 

 quently nearly vertical. In a few species these ridges are broken into 

 a series of tubercles, which are sometimes nearly as distinctly separated 

 as in the Mamillarias, and in others are partly confluent, until in the 

 extreme cases they can only be traced by slight prominences upon the 

 ridges. Whether moderately or strongly developed these projections are 

 termed tubercles as in the other genera, and each bears a cluster of 



