SCIENTIFIC COMMITTEE, SEPTEMBEE 24. CCXXxiii 



to be traceable to one or two sources, and the Committee would be 

 glad to hear of its occurrence in a wild state. 



Helenium cupreum virescent. — Mr. J. Hudson, V.M.H., sent a 

 specimen of a virescent and proliferous form of Helenium cupreum 

 from the garden at Gunnersbury. 



Alpine plants attacked by dodder. — Miss Willmott, V.M.H., sent 

 an interesting series of alpine plants attacked by a species O'f dodder, 

 including Sedum album, S. elongatum, Daphne alpina, a mossy 

 Saxifrage, Thymus Serpyllum, Campanula rotundifolia, Thalictrum 

 minus, Phlox subulata, and Dianthus deltoides. The species of Cuscuta 

 could not be identified as it had no flowers. 



"Reversion " in Black Currants. — Mr. E. A. Bunyard sent an 

 interesting series of specimens illustrating his idea that the ' ' reversion ' ' 

 to which the attention of the Committee was recently directed (see 

 pp. cxxiii, cxxiv) was the result of the development of lateral branches 

 after injury to the terminal bud. Among the specimens sent (which 

 did not appear to be all of one variety) were shoots showing mechanical 

 injury, shoots probably injured by the shoot-cutting weevil, and shoots 

 injured by " big bud," all exhibiting the reverted foliage, with normal 

 shoots for comparison. The hypothesis, the Committee considered, 

 hardly accounted for the persistence of the reversion " so that whole 

 bushes were affected season after season. 



Upon this subject Mr. Bunyard writes in Gard. Chron., August 24, 

 1912, p. 159, as follows: — 



" Nettleleaf " or " Reversion " in Black Currants. — It seems uncer- 

 tain if this may be considered a new " disease," or if it is merely that 

 more attention is now paid to such matters than in former days. Too 

 much stress cannot be laid upon the point that more facts are needed 

 as to its distribution and development before any opinion can be formed 

 as to its cause. In the hope that a suggested explanation may stimulate 

 the production of these facts, I venture to place before your readers a 

 tentative solution of this question. The facts which I have observed 

 and gleaned are as follows : (1) It may be seen in one-year cuttings and 

 in bushes of all ages. (2) It is not confined to any one variety. (3) It 

 is often followed by " big bud." (4) It is reported to have a tendency 

 to spread from a given centre in a plantation — ^that is, where in one 

 year one bush may be affected, the following years show neighbouring 

 bushes also suffering. (5) A close examination shows that in all cases 

 (in the writer's experience) the leading bud of the shoot has been 

 damaged by birds or breakage, and this has caused the side buds to 

 develop fresh shoots, and it is these shoots which show the well-known 

 nettleleaf " appearance. Conversely, it of course holds that in no 

 case is it seen on a main shoot which has its leading bud growing and 

 undamaged. (6) A similar leaf variation may be seen occasionally in 

 Eed Currants. One other consideration must be put forward, and that 

 is that the Black Currant is subjected to a very severe method of 

 pruning, and all fruit is borne upon vigorous wood of the current year. 

 The explanation I suggest is this : The damage to the leading bud may 



