6o The Scottish Naturalist. 



at Perth, and suggested that it might be regarded as an 

 incipient species. Shortly after, Lindberg, unaware of Dr. 

 Stirton's notice above-mentioned, described, in "Grevillea" for 

 Dec. 1875, ^ "^w Zygodon which he had gathered at Crouma- 

 gloun, in the Island of Gotland, &c., under the name of Z. arista- 

 tus. In a letter to me he acknowledges that this is identical with 

 Z. Stirtoni so long known to Scottish botanists, but unkno^vll to 

 him until my specimens reached him last year. It is quite 

 different from his Z. rupcstris. Whether Lindberg will consider 

 Dr. Stirton's description of Z. Sfirto?n\ when it is brought under 

 his notice, to be sufficiently full and public, I do not know. 

 I think it is, and that therefore the earlier name should be 

 maintained, even although, singularly enough, Schimper takes 

 no notice of either plant in the 2nd edition of the Synopsis. Is 

 it possible that he has done so, because, in his maturer judgment, 

 he rejects both as unworthy of a place, even as varieties ? 



It is singular how an error once let loose holds its ground. 

 Schimper, Boulay (Flore Cryptogamique de 1' Est), Wilson, C. 

 Mueller, Sir W.J. Hooker, and others, all describe Z. viridissinms 

 as having no peristome. Old Bridel, who deserves to be 

 oftener consulted than he is at the present day, was more 

 accurate and cautious. His remarks upon the subject in 1826 

 are quite interesting. " Turnerus non vidit, Hookerus non 

 memorat, nos aut nudum deprehendimus, aut semidestructum 

 cum dentium perditorum vestigiis nonnullis." Hence it appears 

 that the modern error originated in some one refusing to admit the 

 testimony of Bridel and Smith to the effect that they had seen 

 the peristome, and in, coming to the conclusion that what was 

 not seen occasionally was never seen, and consequently did not 

 exist. After examining upwards of 50 capules, and finding 

 traces of a peristome in nearly the half of them, and perfect teeth 

 in a good many of them, I must give my testimony altogether 

 in favour of Bridel. 



I do not wish to conclude that what I myself have been 

 unable to see has not been and cannot be seen, but I susjDect 

 that there is an error of long standing connected with Dicranella 

 Grevilkana. With whom the error originated (if error it be) I 

 have not been able exactly to discover, but all the authors who 

 describe this moss declare the inflorescence to be monoicous, 

 and fix upon this as one of its distinctive characters. For the 

 following reasons I doubt if this be so. On coming home last 

 year from Glenshee, where I had gathered D. Grevillcana in 



