272 THE JOUKNAL OF BOTANY 



ford . 



L. x 



—R. angl osaxonicus Gelert x rudisVf. & N. ; Derby. 

 idcBiis L. ; Dorset, Hants, Surrey, Staffs (I add Suss< 



R. ccesius 

 Sussex). These 



are sufficient to show that a fair number of British hybrids exist, 

 and are certified by Mr. Eogers ; I do not wish to throw doubt 

 upon others that have been recorded by omitting them here. 

 They may be perfectly barren, as I have seen a large bush 

 of R. leucostachys x rusticanus in Suffolk, or with a few perfect 



drupes which may contain fertile seeds; e.g. the Rev. E. S. 

 Marshall and I saw a large colony of R. ccesius x idaus north 

 of Arundel in 1901, and could only find one single drupe each 

 in the whole lot. It is not unlikely that some of the numerous 

 R. diimetorum forms are hybrids or of hybrid origin. I have 

 seen one of these in large quantity on Breamore Down, Hants, 

 entirely barren, and judged both by Dr. Focke and myself to be 

 a hybrid. 



Geum intermedium Ehrh. The plant I am familiar with in 

 Dorset and Wilts is undoubtedly Q. rivale x tirbanum, and this is 

 no doubt the common view. Mr. G. C. Druce assures me that it 

 is fertile, and its seed is offered by the Cambridge Botanic Garden. 

 Potentilla produces in this country the three hybrids between P. 

 procnmbens, reptans, and silvestris. Mr. Marshall thinks that some 

 of those that have been met with may be secondary crosses with 

 the parents, and quotes Focke to the effect that fruit is produced, 

 though sparingly, in this group of hybrids. 



In the genus Rosa, M. Crepin held distinctly that some forms 

 were of hybrid origin, notably the groups of R. involuta and 7?. 

 hibemica. The latter name has been given to forms of R. spinosissima 

 X canina or x glauca ; while R. spinosissima hybrids with R. mollis 

 and tumentosa vars. have given us R. involuta and many of its 

 varieties. There is recorded besides R. pimpinellifolia x rubiginosa 

 from Kent and Perth ; and Mr. Marshall also tells me that Major 

 Wolley-Dod has found a rose which seems to be R. tomentosa x 



tomentella, and that Mr. Eogers considers R. pseudo-rusticana to be 

 R. arvensis x systyla. With regard to fertility or otherwise, Mr. 

 Marshall has noticed the fruits falling off before maturing in some 

 R. involuta forms ; Rev. W. R. Linton has noticed R. mollis x 

 spinosissima in Chee Dale quite sterile. On the other hand, Mr. 

 Baker describes the fruits of several R. involuta varieties ; Mr. 

 Druce believes R. mollis x spinosissima produces fertile seeds. My 

 own impression is that some rose hybrids at least are fertile. Lord 

 Penzance has produced several striking hybrids between R. rubigi- 

 nosa L. and sundry old-fashioned garden roses ; and Messrs. Keynes, 

 Williams & Co., of Salisbury, who deal largely in these interesting 

 products, have written in answer to my question that these " Hybrid 

 Sweetbriars produce fertile seed in abundance, but the seedlings 

 produced by it nearly all partake of the Sweetbriar, very few of 

 them indeed showing any tendency to produce plants like the 

 parents : many of the other Hybrid Roses produce seed more or 

 less freely, but their offspring is very erratic and uncertain." It 

 seems to follow from the evidence that, while some hybrid rose- 

 bushes have been observed not bearing perfect fruit, the contrary 



