CXViii PROCEEDINGS OF THE ROYAL HORTICULTURAL SOCIETY. 



Scientific Committee, August 18, 1908. 



Mr. E. A. Bowles, M.A., F.L.S., in the Chair, and eleven members 



present. 



Aliens in garden soil. — Mr. Fraser, F.L.S., showed a specimen of the 

 alien weed, Amaranthus retroflexus, a North American plant which had 

 appeared in a garden at Kew, though no seeds or plants had been received 

 from North America and planted in the garden. He thought that the plant 

 had possibly arisen from a seed introduced with merchandise either from 

 North America or from the Continent, where also the plant has become 

 a weed. He has noticed other instances of plants which had probably 

 been introduced in a similar way, and had become weeds in gardens, viz., 

 Datura Stramonium, Euphorbia Esula, and Sisyrinchium angustifolium, 

 while Papaver somnifcrum, Oenothera biennis grandiflora, and Oxalis 

 corniculata rubra, originally cultivated, had quite frequently become 

 garden casuals, and certain British wild plants, e.g. Chcnopodium rubrum, 

 Epilobium roseam, E. hirsutum, Lychnis alba, and Silene Cucubalns 

 often behaved in a similar fashion. 



Bubus laciniatus. — Mr. Fraser also showed a specimen of a seedling 

 form of Bubus laciniatus which he had collected on West End Common, 

 Esher, where the seed had been deposited in all probability by a bird. 

 The origin of this form appeared doubtful, but it seemed to differ only in 

 the laciniated leaves (the sepals and petals also being cut) from Bubus 

 vilHcauHs var. Selmeri. 



Bose canker. — Mr. Giissow showed specimens of a disease of Roses 

 which was very prevalent in Ireland, and which started in the form of 

 reddish spots on the shoots. These spots soon died, the dead tissue con- 

 tracting and cracking. A callus formed around the edges of the wound, 

 and this was frequently damaged by frost, &c, until a large cankerous 

 growth was produced. He attributed the beginning of the injury to the 

 fungus Coniothyrium Fuckelii Sacc, the conidial form of Leptosphaeria 

 Goniothyrium (see p. 222). 



Double Genista tinctoria. — Mr. Bowles showed specimens of double 

 flowers of Genista tinctoria from Canon Ellacombe's garden, and others 

 having numbers of bracts below the inflorescence. This had apparently 

 arisen from the presence of a small dipterous larva belonging to the 

 Cecidiomyidae, which Mr. Saunders, F.L.S., reported as that of Aspondylia 

 genistae. This species is known to attack and form galls on the ends of 

 the shoots of Genista germanica in exactly the same manner as in the 

 shoots exhibited. Another species, A. ulicis, forms galls resembling 

 1 lower-buds on U. europaeus. There appears to be no record of G. 

 tinctoria being galled by a fly, but some of the galls in the present 

 specimens contained no less than fifteen or twenty grubs feeding upon 

 the leaves forming the gall, particularly at their base. 



Abnormal Orchid.- From Messrs. Hugh Low came an Orchid, 

 Eodriguezia crispa, showing an abnormal condition in the spike; the 

 bracts were much longer than the flowers, and very closely grouped at the 

 end of the inflorescence. 



