280 THE JOURNAL OF BOTANY 



NOTES ON RUBI SUBEKECTI.- 

 By E. G. Gilbert, M.D. 



RuBUS Id^us L. This is so variable in the form of its leaf 



and the amount and character of its armatm^e that it seems 

 likely that deductions have been drawn from similar differences 

 among other Kubi which those differences did not justify. The 

 striking peculiarities of B. Idcsus have happily preserved it from 

 this dismemberment. It is admitted to differ from B. ccssius 

 more than from any Buhus, and yet to cross with it. Why, then, 

 may we not think it inohahle that all the intermediate Rubi cross 

 freely ? Perhaps because Idmts and the Ccssii flower earlier than 

 nearly all the other Rubi. I have met with only B. I. x ccesnis 

 and B. I. x subkcstris (Lees) ; the latter so much resembles the 

 var. ohtiisifolius (Willd.) that it seems to me not improbable that 

 they are identical. 



EuBUS Fissus Lindley. I have not found this near Tunbridge 

 Wells, but on the north-east end of Chislehurst Common it is 

 abundant, growing only a foot or two high. A large proportion of 

 its leaves are 7-nate ; this I take to be really due to defective 

 formation of the terminal leaflet, as there are many instances of 

 leaves in conditions intermediate between that and the 5-nate 

 leaves, and also many leaflets curiously cut and manifestly im- 

 perfectly developed in other ways. At the other end of the 

 Common B. carpinifolius was abundant, and w^here it extended 

 up to the fissus were plants combining their features in a very 

 puzzling way. In having thin leaves not conspicuously hairy be- 

 neath this Chislehurst fissus is not true to the description in Mr. 

 Rogers's Handbook. I have, however, a specimen from Dunkeld 

 which is more so : this is a remarkably strong, sturdy plant, and 

 has no 7-nate or cut leaves, affording a remarkable contrast to the 

 Chislehurst plant ; otherwise it is much like it, and Mr. Rogers 

 kindly confirmed my determination as "undoubtedly strong B. 

 fissus." I have, however, found close to B. suberectus and coryli- 

 folms plants wonderfully like this, which I could hardly doubt 

 were hybrids of the two. One of these seemed to me indis- 

 tinguishable from a specimen of M. Sudre's sulcatiformis, which 

 he thinks to be B. suberectus x B. ccesius ; and also from some 

 specimens of suberectus and fissus in the Kew Herbarium. Is not 

 the suggestion that we ought to be careful not to confuse such 

 hybrids with the pure Suberecti justified by this ? Moreover, 

 Mr. Rogers notes, in his Handbook, that B. fissus becomes " more 

 like sitberectus in damp shady places"; I have also seen B. 

 plicatus extend down to the damp lower corner of a steep north 

 slope, and there very closely resemble suberectus asiidfisstcs. The 

 only distinctive mark of B. fissus which holds good in the speci- 

 mens of the Suberecti in the National Herbaria is the " many 

 slender subulate " prickles. 



It is noteworthy that the descriptions of fissics and corylifolius 



* See Journ. Bot. 1907, 209. 



