SCIENTIFIC COMMITTEE, AUGUST 23. 



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Scientific Committee, August 23, 1901. 



Dr. M. C. Cooke in the Chair, with nine members present, and Professor 

 Liberty H. Bailey, of Cornell University, and Professor L. J. Jones, 

 of Vermont University, Burlington, U.S.A., attended as visitors. 



Diseased Potentillas. — Mr. Saunders, F.L.S., reported as follows on 

 some specimens submitted to him : — " The diseased blossoms of a Potcn- 

 tilla, exhibited by Mr. Bowles, are attacked by eelworms, and probably by 

 the species which is the cause of the ' Cauliflower disease ' in the cultivated 

 Strawberry (Aphelenchtis fragrance), a disease which has been known to 

 ruin nearly half the crop by rendering the flowers abortive. I am afraid 

 that there is no real cure for this infestation, and that the best thing to 

 do is to burn the affected plants and the soil round their roots. If the 

 plant be a valuable one, it might be of use to cut away all the parts which 

 show any sign of being infested, and to remove as much as possible of the 

 soil round the roots. The following dressings have been found very useful 

 in the case of Clover which was attacked by the ' stem eel worm ' (Tylenchus 

 devastatrix) : three parts of sulphate of potash, and one of sulphate of 

 ammonia or sulphate of iron." 



Leaf-miner in Lilacs dc. — Mr. Saunders also reported that the leaves 

 of the common Lilac, exhibited by Mr. Holmes, F.L.S., were attacked 

 by the caterpillars of the "Lilac-moth" (Gracillaria syringella). The 

 caterpillars had, however, all left the leaves to pupate. The Willow leaves 

 also shown by him were attacked by a small beetle, Phratora vitellines ;. 

 and some other Willow leaves by the grubs of one of the saw-flies belong- 

 ing to the genus Nematics. The leaves of the shoots of Black Currant, 

 also submitted to Mr. Saunders, were covered with small transparent blister- 

 like pustules, the cause of which he could not determine. On examining 

 them under a microscope he could find no trace of insects, mites, or fungi 

 in them. There were a few acari and thrips on the leaves, but they were 

 not the authors of the pustules, nor of the injury to the leaves. Mr. 

 Saunders suggested that the pustules may be of bacterial origin. Cut off 

 and burn all the shoots bearing leaves which are affected. 



Fungus on Charred Gorse. — Some specimens of fungi observed on 

 Gorse after being burnt were submitted to Dr. Cooke. 



Fungus on Cypripedium Leaf. — A leaf attacked by a fungus was 

 submitted by Mr. Douglas, V.M.H., and referred to Dr. Cooke for 

 examination. 



Variegation in Ferns. — Mr. C. T. Druery, V.M.H., sent a unique and 

 interesting example of symmetrical variegation in a British Fern in the 

 form of a frond of Polystichum angulare var. pulcherrima Moly. found 

 many years ago in Dorsetshire. The plant is perfectly constant, and, 

 curiously enough, perfects its fronds as purely green ones, the variegation 

 appearing subsequently as they ripen. The Fern is furthermore interest- 

 ing as being the only known example of a constant aposporous form of 

 P. angulare, the sickle-shaped, inferior pinnules developing prothalli from 

 their tips when layered. The resulting sexual plants, however, are irregular 

 and depauperate, with extremely rare exceptions. Mr. Druery was indebted 

 for this plant to Dr. Stansfield, of Reading. 



s s 2 



