and " Lichenastrum alpinum nigricans, foliis capillaceis nflexis" {A. falcata). 

 Linnaeus also had two species to which he referred the Dillenian mosses, 

 and placed under Jungermannia as y. alpina and jf. mpestris, but he evidently 

 had no correct idea of them, as the specimens in his herbarium belong as 

 regards the former to A. petrophila- Ehrh., and the latter to A. ohovata Thed. 



The genus was first established by Ehrhart in honor of his friend 

 J. G. R. Andreas, an apothecary of Hanover, and his excellent character of 

 it stands as follows : " Perichsetium squamosum ; squamae lanceolatse, carinatae, 

 imbricate. Anthophorum longitudine perichaetii. Calyptra conica brevissima. 

 Stylopodium nullum. Conioecium oblongum, subtetragonum, 4 sulcatum. 

 Apophysis turbinata. Valvulse 4 carinatae, angulares, basi apophysi apicibus 

 conjunctorio adnatae. Suturse laterales ex medio sursum deorsumque 

 versus dehiscentes. Conjunctorium obtusiusculum. Dissepimentum nullum. 

 Styliscus cylindricus. Sporae subtilissimae." 



Ehrhart knew only one species A. petrophila, and confusion at once crept 

 in, for this was universally regarded as identical with our A . alpina, due no 

 doubt to the curious fact, that this common British species is almost entirely 

 absent from the continent of Europe ; then Hedwig defined the 4 valves of 

 the capsule as peristomial teeth united to a persistent operculum, and the 

 confusion was complete when he and Mohr made A. petrophila Ehrh. into two 

 species, A. alpina and rupestris, which they considered to be synonymous with 

 those of Dillenius, and in this error were followed by nearly all subsequent 

 writers down to our own day, until Thedenius cleared matters up in his 

 classical paper," Ohservatinnes de enervihns Scandinavia speciebus generis Andrecea," 

 and Schimper finally settled the genus in his exquisite monograph in the last 

 part of the Bryologia Europcea. It may be noted that the British authors 

 who possessed the true A . alpina still retained the name rupestris for A . petrophila 

 Ehrh., which ^had been given to that form of it with secund leaves, the 

 var. homomalla. 



That Mohr, however, was not altogether satisfied with his determi- 

 nation is evident from what he says under A. rupestris, Hedw. ? (Bot. 

 Taschenb, p. 384) as follows : — " It is not to be denied that the leaves of 

 A . alpina and rupestris do not differ, except that in the latter the apex of the leaf 

 is laterally curved, from which the leaves become remarkably homomallous. 

 Hedwig incorrectly ascribes to A . alpina, leaves smooth at hack ; to A. rupestris, 

 leaves muricate or papillose at back; both are truly very lightly papillose at 

 back under a high power." Bridel was evidently of opinion that they were 

 not distinct, for he states that he considers these forms so similar that they 

 can with difficulty be regarded as proper species. It is also clear that 

 Hedwig had specimens of the true A. alpina, but failed to distinguish them, 

 for that species has smooth cells, but A . petrophila has them distinctly and 

 coarsely papillose. With respect to this important character of smoothness 

 or papillosity of the cell walls, it may be well to refer to a paper by 

 Schliephacke, " Ueber das gemts Andreaa," in Verhandl. Zool. Bot. Ge^ells. 

 Wien XV., p. 423 (1865), where these characters are contrasted, both in the 

 natural state and after treatment with caustic alkali. 



The other European Andreceas not found in Britain are, A. papulosa 

 LiNDB., an excellent species from Spitzbergen and Mt. Tjidtjak, in Lapland; 

 A. obovata Thed., A. Hartmani Thed., and A. Blyttii Schimp., all three 



