I02 BRITISH GALLS 



author thought that two varieties of lichens described by 

 Nylander were probably nothing more than malformations 

 caused by the presence of similar parasites. These lichens 

 are recorded in Leighton's " Lichen Flora of Great 'Britain" 

 (3rd edition) as Ramalina scopulorum Dicks., var. incmssata 

 Nylander, with the thallus thick, rigid, tuberculoso-dif- 

 formate, and Ramalina cuspidata Arch., var. crassa Del., with 

 the thallus similarly deformed^the former from Harlech 

 Castle, Wales, La Moye and Mont-Orgueil Castle, Jersey ; 

 the latter from rocks under Vale Castle, Guernsey. Miss 

 A. Lorrain-Smith, F.L.S., informs me that she examined 

 the specimens in the British Museum collections, just 

 after the publication of Zopf's paper, and found fragments 

 of mites, but, as far as she is aware, no one has identi- 

 fied the species. These interesting galls deserve to be 

 better known and the causer identified. 



Experimental Galls 



Peyritsch published in 1888 some very interesting obser- 

 vations concerning experimental production of galls by 

 placing mites (species unknown) on various plants. In 

 Valeriandla and Valeriana the deformities were chiefly of the 

 floral organs; in several species the flowers were doubled, in 

 others the leaves were rolled inwards, contorted, discoloured, 

 and covered with the usual pubescence. In the Cruciferae 

 the malformations also consisted of curious modifications 

 and proliferations of the floral organs— e.g'., in Myagrum per- 

 foliafum Linn, the flower was deformed and slightly double. 

 Dr. Kerner's speculations concerning the possibility of the 

 transmission of double flowers, when these have arisen 

 through the influence of mites, are of great interest, and no 

 apology is necessary for quoting them at length here. He 

 noted in 1877 that some plants of Veronica officinalis produced 

 double flowers in consequence of the settlement of mites 

 upon them, and that adjacent plants without mites produced 

 normal flowers. In the following year the mites attacked 



