146 



being found which would indicate the transition from one towards the 

 other species. Notwithstanding this, intermediate forms are occa- 

 sionally seen, which exhibit a series of steps from the common prim- 

 rose {Primula rulgaris) towards the cowslip [Primula veris), and 

 which have usually been mistaken, in this country, for a different spe- 

 cies {Primula elatior, of Jacquin). On the other side, there is a 

 variety of the cowslip which makes a considerable step towards the 

 primrose, in its larger, paler, and nearly flattened limb of the corolla. 

 This latter is the Primula veris, var. major, of the London Catalogue. 

 It has been sup'posed that those varieties of the primrose which ap- 

 proximate nearest to the cowslip, are hybrids or mule-breeds between 

 the two received species. This conjecture may be coiTect, although 

 the supposed hybrid wants one of the peculiarities usually expected 

 in true mules ; namely, that of sterility. (See Phytol. i. 9, 232, 1001). 

 It would not be difficult to adduce other examples of two reputed 

 species apparently passing one into the other by intermediate varie- 

 ties. But in the pages of a monthly periodical I can give only few 

 examples in any detail. In most instances, perhaps, where two al- 

 leged species are thus connected by intermediate varieties, the dis- 

 tinctness of the two species is called in question for that very reason. 

 Thus, in the eyes of some botanists, the cases would resolve them- 

 selves into examples of variation in single species, rather than instan- 

 ces of connecting links between two species. Teucrium scordioides 

 passes into Teucrium Scordium, by a gradual variation of character; 

 but the former is rightly deemed a dubious species. So eJso of Erica 

 Mackaiana, a very dubious species, which may be traced, step by step, 

 into a form scarce distinguishable in any way from Erica Tetralix. 

 Betula glutinosa passes into Betula alba ; Veronica humifusa shades 

 into Veronica serpyllifolia ; Rumex conglomeratus into Rumex san- 

 guineus ; Avena alpina into Avena pratensis ; Festuca loliacea into 

 Festuca pratensis ; F. pratensis into F. elatior ; F. elatior into F. 

 arundinacea ; Viola lactea into Viola flavicornis ; V. flavicornis into 

 V. canina ; &c. &c. 



From such facts as these — whether seen in the wilds, produced in 

 the gardens, or recorded in books — are we not forced to concede to 

 the transitionists, that the notion of permanently impassable limits 

 between species, whether true or false in itself, wears rather a doubt- 

 ful aspect at present ? Still, we cannot altogether concede that the 

 mere existence of wide varieties, or of intermediate forms between 

 alleged species, will sufficiently warrant a presumption against the 

 reality of such limits. Moreover, it is to be remembered, that some 



