92 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



CEREUS X KEWENSIS. 



By A. Worsley, F.R.H.S. 



This hybrid (C. MacDonaldiae x C. nycticalns (?) )* was raised in the 

 Royal Gardens, Kew, about twenty years ago. It does not retain 

 the floriferous character of C. MacDonaldiae, and has only recently 

 borne flowers. In October, 1910, and again in June and in October, 

 191 2, flowers were produced but no fruit resulted. 



C. MacDonaldiae is a native of Honduras and comes in Schumann's 

 classification under " Series Principales " [Branches with 5 to 7 angles 

 or ribs, sometimes cylindrical when old ; spines not multiplied in old 

 age ; sepals yellow or brown, rarely red, petals while] and is given this 

 short specific description in the Keys of his Monograph of Cactaceae, 

 viz. — Areoles only with spines, without hairs. Branches almost round, 

 sometimes tubercled ; flowers very large, yellow and white. I have 

 grown C. MacDonaldiae for many years and have found it very 

 floriferous when allowed to cling to the damp wall of a hot-house 

 and ramble along the roof. One year I gathered more than ten 

 dozen blooms off a single plant. The flowers measure from 12 to 

 14 inches across, and, as they expand just after 6 p.m., they are of 

 great value for the decoration of the dinner-table. 



But it is not necessary to grow this plant in a hot-house, for it 

 will endure slight frost without injury. One very large old plant 

 survived nine degrees of frost, although it was seriously crippled by 

 the trial. Yet the flowers borne in a green-house are not so large as 

 they would be under more favourable conditions. 



C. x kewensis does not seem to differ from ihis parent in its cultural 

 requirements. Its flowers are distinct and are perhaps of equal 

 beauty. Of all the published figures they most nearly resemble 

 those of C Lemairei [Garden, January 30, 1892] but differ in respect 

 of scales, and stigmas ; moreover, C. Lemairei belongs to the series 

 " Triangulares." 



C. x kewensis is a fugacious, night -flowering plant, of good 

 constitution. 



* There is some doubt about the parentage. It is certain that C. Mac- 

 Donaldiae was one parent, but the other parent is doubtful. There is a record 

 of a cross with a garden Phyllocactus, but no trace of this can be seen in the 

 hybrid, and all other attempts [I have tried more than fifty times] to cross 

 C. MacDonaldiae with Phyllocactus have failed to produce seeds. I have sug- 

 gested C. nycticalus as the most probable parent. 



