163 



I must now become, temporarily, a sort of advocate for the traiisi- 

 tionist, in adducing some examples which look very like cases of 

 transition. Assuredly I can bring none so wide as the alleged con- 

 version of the rye into the oat; which, I may safely assert, is credited 

 by extremely few botanists. But facts of minor conversion are not 

 altogether wanting ; and if more diligently looked for, they might be 

 found more numerous than is at present supposed to be the case. 



Viola canina [Linn.) and Viola flavicornis {Smith). — The dog's 

 violet is the commonest species of its genus in Britain. Being found 

 under very diflferent conditions of soil, shelter, humidity, &c., it runs 

 into several varieties; so that the line between this one and allied 

 species (so reputed) is drawn differently by botanical authorities. One 

 of these (species or varieties, as opinions may run) is the Viola flavi- 

 cornis of Smith — not the dwarf variety figured under this latter name 

 in ' English Botany ' (2736) ; but the one described in ' English Flo- 

 ra,' and specimens of which are preserved in Smith's herbarium. The 

 V. flavicornis grows on open commons, and it presents several differ- 

 ences of physical character, when compared with the ordinary forms 

 of V. canina which are seen in coppices and hedge-rows. The dif- 

 ferences are not very strong, yet are quite as wide as those which are 

 deemed sufficient to distinguish species in the same genus, or those 

 in other genera. It has been stated, also, that these peculiarities re- 

 main unchanged in living specimens after removal into a garden. 1 

 have not found this stated fact to hold true with a plant brought into 

 my own garden. An example of V. flavicornis was removed from a 

 common in Surrey, into my garden, when flowering, in 1841. Being 

 absent in the summer of 1842, 1 did not see it during that season ; 

 but in 1843 and 1844, it had assumed so much the size and shape ol 

 leaf, with other peculiarities which belong to V. canina, as to be bare- 

 ly (if at all) distinguishable from some forms of the latter, when press- 

 ed and dried. Moreover, I have raised plants in a flower-pot, from 

 the seeds of a wild example of V. flavicornis, which came still nearer 

 to the more usual form of V. canina than did the changed garden 

 plant. In neither case, has the typical form of V. canina been fully 

 acquired — perhaps, it was not to be expected so rapidly ; but toge- 

 ther with a series of wild specimens in my herbarium, they suffice as 

 links of connexion between the two reputed species. 



Polygonum maritimum {Linn.) and Polygonum Raii {Bab.) — The 

 plant which is now becoming familiar under the name of Polygonum 

 Raii, has been imperfectly known to the botanists of England for 

 many years. About the year 1831, when a very young botanist, I was 



