102 
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. incrassata 
Nylander, with the thallus thick, rigid, tuberculoso-dif- 
formate, and Ramalina cuspidal a 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 
V alerianella 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- 
foliatum 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 
