IV.] GEUM, RUBUS. 91 



maturity before the anthers ; though as it retains the 

 capability of fertilisation after the anthers have opened; 

 the flowers are doubtless often self-fertilised ; which 

 from the position of the anthers' probably happens 

 more frequently in the Bird Cherry than in the Black- 

 thorn. The flowers are melliferous. The British 

 species of Spiraea, on the contrary, contain no honey, 

 but are rich in pollen and are consequently visited by 

 insects ; which from the weakness of the petals, gener- 

 ally alight on the stigma, and thus effect cross-ferti- 

 lisation ; though the flowers, if not visited by insects, 

 fertilise themselves. Among the foreign species of 

 this genus, several are melliferous. 



Both our English species of Geum {G. rivale and 

 G. urbanum) are melliferous ; but the flowers of G. 

 rivale are much larger than those of G. tirbamim, and 

 more frequently visited by insects. 



The genus Rubus is very variable, and there are 

 great differences of opinion among botanists as to the 

 specific limits, and the number of species. Bentham 

 admits five, though even these, he adds, "will very 

 frequently be found to pass imperceptibly one into 

 the other." The Raspberry {Rubies idmis) is so called 

 because it is said to be very frequent on Mount Ida, 

 where in 1872 Mr. Grant Duff" and I found in abun- 

 dance a species, which if not identical with, was very 

 near, our R. idcBus. This species though it secretes 

 honey, is not apparently a great favourite with insects, 

 and frequently fertilises itself. The flowers of the 

 Blackberry {R. fritticosus), on the contrary, are much 

 more conspicuous, and the stamens are turned more 

 outwards, so as to leave more room between them- 



