26 



LICHENOLOGICAL MEMORABILIA. 



my "Britisli Graphidese" (1854), p, 13, t. 5, f. 8, to be actually 

 a Lecidea, which now bears the name of L. trochodes, and I have 

 been informed on good authority that Dr. Nylander only knows 

 the plant from this figure in my Monograph. 



By the kindness of Mr. Crombie I have been permitted the 

 microscopic examination of the unique speciiuen of Eimula7ia 

 limbot'ina, Nyl., which he gathered on Craig Guie, Braemar, and 

 which bears this name in Dr. Nylander's own handwriting. This 

 examination shows that Lecidea trochodes and Rimularia limborina 

 are perfectly identical both in external characters and internal struc- 

 ture and formation, except that the spores, in other respects identical 

 are in the latter plant slightly larger, but still only so in a degree 

 observable in most lichens, and not sufficiently dissimilar to separate 

 the plants. As figures convey more distinct and adequate ideas 

 than mere descriptions, I here add figures of the structure of the 

 two plants and their spores (see plate 52, figures 1 and 2). From 

 this it will be evident that Rimularia limborina, Nyl., must be 

 erased from our British Lichen-Flora, and merged in Lecidea 

 trochodes, (Tayl.). 



Mr. Crombie has also supplied me with an authentic specimen of 

 Lecidea subgi/ratula, Nyl. This possesses umbonate apothecia, 

 resulting most probably from the same deformation as stated by 

 Dr. Fries with, regard to L. trochodes. But in L. subgi/ratula, 

 Nyl., the spores are colourless, and only half the size of those of 

 L. trochodes (see fig. 3) ; consequently this must be considered a 

 good and distinct species, and that Dr. Fries is in error in regard- 

 ing it as synonymous and identical with L. trochodes^ 



EXPLANATION OF PLATE 52. 



L. trochodes. (e) Section of apothecium. (g) Apothecium aa seen from above. 

 (/) Spores inagn. 1200. 

 Rimularia limborina. (c) Section of apothecium. (d) Spores magn^ 1200. 

 L. subgyratula. (a) Section of apotheciam. (6) Spores magu. 1200. 



"ATLAS DER DIATOMACEENKUNDE." 



The fourth and fifth parts of this work are now issued. 

 Plate 13 contains a continuation of the Panduriform navieula 

 {Diploneis group), viz., N. didyma, N. gemma, and its varieties, 

 egena, and densestriata ; N. j^rominula, N. futilis, N. gemmatula, 

 N. Kiitzingii, N. diplosticta, N. splendida, J^. bomboides, N. 

 muscceformis, N. entomon ; besides these are several " critical forms'' 

 given for comparison ; these seem to unite several of the so- 

 called species. Forty-nine figures are given ; making in all 154 

 figures of this group. 



Plates 14 to 18 inclusive are devoted to the genus Cainj)7j- 

 lodiscus, and contain 118 figures. About one-half of these are 



