NOTES ON BRITISH RUBI 133 



Rubi commonly held to be distinct species- Another form of 

 plicatus^ or resembling it, is not uncommon about here. It is of 

 lower growth, and has very numerous small, very strongly hooked 

 and decurved prickles, and leaves very doubly and acutely serrated. 

 This form is not, however, very distinct from the last. I suspect 

 it has often been mistaken for R. nitidus, and may be R. hamu- 

 losus L. & M. 



R. Rogersii Linton. A specimen lent me by Mr. Rogers, one 

 in his " Set of British Rubi " at Kew (labelled opacus), and one or 

 two which I have gathered, are all precisely alike; but none have 

 the cordate leaves or crowded prickles mentioned in his Hand- 

 book. Mr. Rogers himself cannot always distinguish even living 

 hemistemon from Rogersii. M. Sudre considers it a subspecies of 

 affinis. I have not a very free acquaintance with it, and may be 

 wrong in suspecting it to be a hybrid between nitidus (Wh. & N.) 

 and affinis (partly from its very thin distribution where I have 

 found it), or a mere variant of the former. It has aciculi upon the 

 calyx like nitidus. 



What I have described as a "third form" of plicatus appears 

 to me to have been included by Mr. Rogers in his description of 

 R. nitidus, and is probably R. hamulosus of Lefvr. & Muell. This 

 is a much commoner plant here than the true nitidus, and appears 

 to me much more like plicatus than it is to the other form of nitidus 

 or to opacus. I suspect strongly that I have found hybrids between 

 it and suberectus, affinis, Balfourianns, and Sprengelii. There are 

 numerous intermediates, perhaps hybrids, also between it and 

 plicatus (hemistemon), which combine their characteristics in different 

 ways. Not improbably, I think, plicatus Bertramii is one of these. 

 Luxuriant and straggling specimens of it, moreover, have been 

 named by some of the most eminent British authorities, I submit, 

 R. lentiginosis, and by me R. integribasis. Its close resemblance to 

 R. orthoclados has also been noticed by Mr. Rogers and me together, 

 as also its resemblance to affinis Briggsianus (Rogers), which Dr. 

 Focke refers to nitidus. By* far the most probable explanation of 

 all this seems to me to be that all the plants referred to are hybrids, 

 with one parent, nitidus (or hamulosus) in common, and therefore, 

 of course, vary a good deal. Their sparse distribution and some 

 of their other features point to the same conclusion. Not less so 

 does the difficulty which the best judges appear to find in dis- 

 tinguishing them clearly from their nearest allies and from one 

 another. This difficulty is evident on carefully inspecting the 

 collections of Rubi in the National Herbaria, from the frequency 

 with which the same Rubus is named differently, and the same 

 name given to different Rubi. M. Costa considers R. integribasis, 



R. hamulosus, and R. holergthros to be all varieties of nitidus. 



I have occasionally met with another plant bearing all the 

 appearance of a cross between R. nitidus or hamulosus and one of 

 the other Suberecti, especially affinis. ^ Some of the specimens 

 labelled R. opacus in the national collections and the " Type Set " 

 are just like these; others so labelled differ from those; and taken 





