432 GENERAL REVIEW. 



sown in a gentle heat. The common Laburnum is one of our 

 most beautiful spring-flowering trees, and being principally 

 raised from seed, is very variable in habit. What is known in 

 nurseries as Waterer's Laburnum is so much superior to the 

 ordinary Laburnum that it seems inexplicable why it has not 

 been everywhere planted. It is not so large in the foliage nor 

 in the individual flowers as the Scotch Laburnum (Cytisus 

 alpinus}, although it may possibly be a cross between it and the 

 common sort. Darwin (see ' Animals and Plants,' i. 416) says 

 that "the belief that Cytisus Adami is a spontaneously-pro- 

 duced hybrid between C. laburnum and C. purpureus is sup- 

 ported by the fact that such hybrids have arisen in this genus. 

 In a bed of seedlings from C. elongatus, which grew near C. 

 purpureus, and was probably fertilised by it through the agency 

 of insects (for these, as I know by experiment, play an import- 

 ant part in the fertilisation of the Laburnum), the sterile 

 hybrid C. purpureo-elongatus appeared. Thus also Waterer's 

 Laburnum, C. alpino-laburnum, spontaneously appeared, as 

 I am informed by Mr'Waterer, in a bed of seedlings." 

 There is a very beautiful golden-leaved variety of Laburnum, 

 which originated as a sport; and this, together with some 

 of the rarer hardy species of this genus, are propagated 

 by grafting or budding on seedlings of the common Labur- 

 num as a stock. Half the seedlings raised are worthless 

 as flowering-plants, and either Waterer's Laburnum or some 

 other good variety should be worked on the seedling stocks, so 

 as to insure good varieties only in cultivation. M. Baltet 

 recommends seedlings of C. alpinus as stocks on which to 

 graft in March and April, or propagate by shield-budding in 

 July and August. Seedlings of Cytisus alpinus form good 

 stocks for Genista multiflora, and seedlings of G. hispanica 

 serve for other varieties, cleft - grafting in spring (March or 

 April) being the most successful method. Scions should con- 

 sist of young growth, with a heel of old wood at the base. All 

 .the slender-flowering kinds, as C. purpurea, C. rosea, C. alba, 

 C. carnea, C. elegans, and C. trifolia, are said not to succeed 

 except cleft-grafted at the desired height. The strong-growing 

 kinds, such as C. Adami, C. biflorus, C. grandiflorus, and others 

 of similar habit, are best propagated by budding or grafting 

 close to the ground, as they are vigorous enough to form 

 stems. WTien the stock is headed off for cleft-grafting, it is 

 essential to the success of the operation that a shoot or bud be 

 left to attract the sap to the scion. Snails are troublesome 

 when the scions are worked near the ground ; place quicklime 

 or barley-chaff around the stocks to keep them at bay. 



