WICHUltA OH HYlilllDS. 



09 



to an arboreous habit in 8. caprea and incana on the one side, and 

 to a fruticose habit in 8. viminalis and cincrea on the other. The 

 rank growth of the senary hybrid from 8. viminalis, purpurea, 

 Zapponum, silesiaca, caprea, daphnoides was indeed very striking ; 

 and in this case, at the age of ten months a single catkin was 

 produced — a circumstance which agrees with Grsertner's instances 

 of the early blossoming of hybrids. 



Traces of a defective feeble development are far more frequent 

 amongst willow hybrids than rankness of growth. 8. ( 2 arbus- 

 cula-\- 3 purpurea) art., a union it is to be observed of distantly 

 related species, put forth every year a strong shoot, which, how- 

 ever, in the course of the summer began to wither. Not one of 

 the numerous plants which were raised from the intercrossing came 

 into blossom, and all gradually perished. A senary hybrid im- 

 pregnated with the pollen of one of its parents afforded a quan- 

 tity of plants. Three of these, 6 \ years old, had attained a height 

 of six feet, forming miserable little trees. Buds we^e formed 

 every autumn which promised well for the following spring, but 

 the wood did not get ripe enough to give strong shoots, so that 

 they always remained weak ; and though they had the best place 

 in the garden, they never produced any blossoms ; and the result 

 even of a hot summer was the same. 8. ( 2 viminalis -f- S daphnoi- 

 des) art., in itself a tolerably strong hybrid, had a rather unfavour- 

 able place near the garden fence. Of fifteen plants, eight were 

 alive on "Wichura's return from his travels, and all of these sickly. 

 A plant of pure 8. viminalis, which had sprung up with the hybrids, 

 and had the same difficulties to contend against, was healthy, a 

 proof of its steady enduring nature. 8. ( $ caprea + <$ daphnoides) 

 art. grew vigorously to a height of from ten to twelve feet, but, 

 though planted in a favourable spot, gradually failed, so that out 

 of six original examples only one was left. 



8.(2(2 (Zapponum + silesiaca) + S (purpurea -f viminalis)) + <$ 

 druinosa) art. was from the first weak and miserable, and all the 

 specimens were overgrown by other stronger hybrids. Fries 

 remarks of 8. rubra, that is 8. ( pur pur ea-\- viminalis), Wimm., that 

 in Sweden all the branches freeze, while this is not the case with 

 8. purpurea or 8. viminalis. He concludes, therefore, in contra- 

 distinction to Wimmer, that it cannot be a hybrid. Wichura 

 proved that it is so by actual experiment. The circumstance, 

 therefore, mentioned by Fries is exactly applicable to what has 

 been said of the comparatively feeble nature of hybrids, and 

 is so much the more interesting since 8. (purpurea -{-viminalis), 



