458 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY 



only one on the plant at a time. They are yellow in colour and about 

 four inches across. It is a native of Mexico. 



Echinocactus. — The stem is short, globose, or elongate, furnished 

 with spines, sometimes very strong, as in E. corniger. The flowers, 

 which have a campanulate tube, are centrally produced, while in Cereus 

 they are found distinctly below the apex of the stem. Discocactus, 

 Malacocarpus, LopJiophora, and As trophy turn are regarded by Schumann 

 as subgenera. Astrophytum is worth generic rank, I think, for A. myrio- 

 stigma (fig. 76), known as 'Bishop's Hood,' and A. Astcrias are both very 

 distinct plants in adult condition and without spines. The species are 

 native from Chili to Mexico. Astrophytum is Mexican. Besides the above- 



Fig. 75. — Leuchtenbergia piuxcins. 



mentioned, E. Emoryi, the ' Fish-hook Cactus,' E. tcxensis, the 1 Devil's 

 Pincushion,' E. Grusonii, and several others are worth growing. 



Cereus. — This genus is one of the best known, and among the species 

 are some of the most imposing of all Cactaceae. It is chiefly marked by 

 tall-growing, angled stems, in C. giganteus of Mexico reaching a height 

 of 60 feet, but other species are recumbent or trailing, or, if erect, may 

 reach no more than a few inches in height. In some species the genus 

 approaches Echinocactus, but as a rule it is easily distinguished, and 

 always so when the stems are elongate, with flowers well below the apex. 

 Several are night-flowering, and these frequently excite great interest. 

 Many have large and splendid flowers. C. peruvianas monstrosus, 

 remarkable as a monstrosity, has been called ' Rock of Ages.' The 

 night-flowering species are very fine ; the principal are C. triangularis, 



