112 FAVERSHAM PLANTS. [April, 



trouble and discomfort to the future historians of the British 

 species. The history of the recent mutabilities in the nomencla- 

 ture of our plants may be an instructive example, for the changes 

 that have been made during the last thirty years far exceed those 

 made during a century previous to 1830. 



Something may be advanced here about the nativity of Sedum 

 dasyphyllum, a plant which is challenged by some and passed by 

 other botanists. Mr. Watson decides against its claims on the 

 ground that the few natural stations where it has been seen are 

 mentioned " on authority not strong, and seldom corroborated by 

 any second observer.^' Seldom corroborated ! How often should a 

 station be reported, and how many times should it be corroborated 

 by subsequent observers, ere it is allowed to pass the ordeal of the 

 sage of Thames Ditton ? The ' Phy tologist ' supplies corrobora- 

 tive proofs of the genuineness of the Perthshire localities, both of 

 Sedum album and S. dasyphyllum ; confirmation strong as Holy 

 Writ can be easily produced, " in precise terms," and attested by 

 hundreds of observers. 



But will any phytogeographer answer this question, viz. are all 

 plants growing on old walls, whether " garden, abbey, or hos- 

 pital " walls, introduced there by cultivation ? If he answers No, 

 and further replies, only a donkey, but no botanical geographer, 

 would ask such a question, — it may be asked, how came the other 

 plants, the Arenaria serpyllifolia, or A.leptoclados, or A. balearica, 

 which grows on the tool-house at Moncrieffe, or Shepherd's-purse, 

 or Groundsel, and a multitude more, on the wall ? These plants 

 are never cultivated, but eradicated wherever and whenever they 

 appear. How are the genuine plants to be distinguished from the 

 spurious ? They all groAv together. The others, it may again be 

 asserted, are common plants, and therefore there can be no ques- 

 tion about the legitimacy of their origin. The other is uncom- 

 mon, it is scarce or rare. It may be asked again, are all rare 

 plants which have the misfortune to grow on Avails to be excluded? 

 Possibly they might grow on natural habitats if there were any 

 present suited to their peculiar economy. 



Mr. Watson's arguments are not convincing; he did not judge 

 accordantly with the evidence, and probably the evidence on Avhich 

 he relied was defective. But a metaphysician should be able to 

 sift evidence, and he should possess in addition the moral ability 

 to decide impartially. 



