2 LABURNUM 



in fact, as we know it to-day. A few years after L. Adami had been put into 

 commerce, a further remarkable phenomenon was observed in connection 

 with this tree. It was found that it had a tendency to "sport" back more or 

 less to both the parent types. This character it has maintained ever since, 

 and to-day almost every specimen of Laburnum Adami shows on its branches, 

 not only the hybrid itself, but pieces of pure L. vulgare and pure Cytisus 

 purpureus that have sprung spontaneously from its tissues. All three flower 

 together, the curious tufts of the Cytisus suggesting witches' brooms. Many 

 authorities have in times past doubted the possibility of a hybrid being pro- 

 duced by grafting, but the correctness of Adam's account has latterly been 

 proved by Prof. Winkler of Tubingen, who has produced graft hybrids between 

 the tomato and black nightshade. Further, a similar instance has been 

 brought to light of graft hybrids between medlar and hawthorn (see Cratasgo- 

 mespilus). These graft hybrids have been termed " chimseras," because 

 there seems to be a mixture of the parents in their tissues, rather than a 

 genuine and entire fusion. The outer tissues are often found under the micro- 

 scope to resemble those of one parent, the inner ones those of the other. 



L. ALPINUM, Presl. SCOTCH LABURNUM. 



A deciduous tree, 20 ft. (rarely 30 ft.) high, with usually a short, sturdy 

 trunk. Leaves trifoliolate, with a stalk I to 2 ins. long ; leaflets oval or 

 obovate, 2 to 4 ins. long, deep green, not so downy beneath as in L. vulgare. 

 Racemes pendulous, slender, 10 to 15 ins. long, carrying numerous golden 

 yellow flowers, each f in. long on a thin stalk \ to \ in. long ; both the flower- 

 stalks and the main-stalk of the raceme are smooth or thinly downy. Seed- 

 pods 2 to 3 ins. long, flat, with the upper seam (suture) distinctly winged and 

 forming a knife-like edge. 



Native of Central and S. Europe ; cultivated in the British Isles for at 

 least three hundred years, probably much longer, but not a native. It was 

 long confused with the common laburnum until its distinctness was noted by 

 Miller in his Dictionary. It differs in the following characters : leaflets larger 

 and less hairy ; racemes longer, and opening two to three weeks later (early 

 June) ; upper edge of pod flattened out into a thin edge in place of the 

 thickened one of L. vulgare. L. alpinum is undoubtedly the superior species 

 for gardens. 



Var. AUTUMNALE. Usually bears a small second crop of blossom in 

 autumn. 



Var. GRANDIFLORUM. Leaflets broader ; flowers larger, racemes longer. 

 Var. MACROSTACHYS is perhaps the same. 



Var. PENDULUM. Branches weeping. 



Var. PILOSUM. Racemes longer, under-side of leaflet furnished with 

 scattered hairs 



An old variety commonly known as " Latest and Longest " is still one of the 

 best of laburnums. 



L. CARAMANICUM, Bentham and Hooker. 



(Bot. Mag., t. 7898.) 



Although described as a small tree in its native country, this species has 

 not yet, in Great Britain, got beyond the dimensions of a shrub 3 to 6 ft. high. 

 It is deciduous, and has a thin habit, making long, straight, erect shoots, 

 which towards the end of the summer produce near the top a number of 

 short, stiff twigs, each terminated by a raceme of flowers. Leaves grey-green, 

 trifoliolate, short-stalked ; leaflets almost stalkless, obovate, with a short 

 abrupt point, from ^ to f in. long, the side ones the smaller. Racemes 

 terminal, erect, 3 to 7 ins. long. Flowers golden yellow, f in, long ; the stalk 



