ON A MINUTE NOSTOC WITH SPORES. 11 



Professor Rcess' is an abstract of the views already propounded 

 by Professor Schwendcner as regards the nature of Lichens, •who, 

 in his turn, seems possibly to have had suggested to him the work- 

 ing out of some such idea as he has arrived at, by the alternative 

 conclusion put forward by Professor de Bary as one or other being 

 a necessary outcome or result deducible from the existent know- 

 ledge of the gelatinous Lichens (Gallertflechten) or the Col- 

 lemacese and allies, and seemingly embracing al«> Ephebe in his 

 generalisation, which is thus enunciated — " Either the Lichens in 

 question are perfectly developed states of plants whose imperfectly 

 developed forms have hitherto stood amongst the Algae as the 

 N-ostocacea3 and Chroococcacea3 ; or the Nostocacerc and Chroococ- 

 caceas are typical Algaa ; they assume the form of Collema, Ephebe, 

 and so forth through certain parasitic Ascomycetes penetrating into 

 them, spreading their mycelium into the continuously growing 

 thallus, and frequently attached to their phycochrome containing 

 cells."* The former of these hypotheses, as is well known, has 

 many supporters, and, seemingly, a considerable amount — at least, 

 in certain instances — of evidence in its favour. The latter hypo- 

 thesis, on the other hand, has found, if fewer, even more staunch 

 adherents, most prominent amongst whom are Schwendener and 

 Reess, and is in fact that alluded to as being recently put forward 

 by him, relinquishing the views supported by him in the earlier 

 portion of his elaborate memoir on the Lichen thallus. 



The little Nostoc to which I have already alluded, and to which 

 I am desirous of directing attention, is a very minute one, though 

 the dimensions of the subglobose or elliptic fronds vary much. It 

 is rather common in moor and certain bog pools. On account of 

 its small size, therefore, readily capable of compression, and its 

 pellucid character, the elegant arrangement of its tortuously twisted 

 rather large moniliform filaments, is often nicely seen, and this 

 causes it to be a very pretty and favourable illustrative example of 

 its type for examination in its entirety under the higher powers of 

 the microscope. Its minute size calls to mind Nostoc minimum 

 (Currey),f but in it the cells are described as quadrate with a sinus 

 at each side, lending a crenate outline to the filaments, and the 

 heterocysts are large, whilst here the cells are orbicular or for a 

 time slightly flattened at the junctions, and the heterocysts are but 

 slightly wider, though longer than the ordinary cells. This plant 

 is probably identical with Nostoc jjaludosum (Kiitz.), though as re- 

 gards anything to be deduced from the heterocysts Kiitzing is silent. 

 But the interesting point connected with it is a single example of 

 it having presented indubitable " spores," and precisely similar 

 nature to those in Sphrcrozyga, &c, but with the peculiarity of 



* Morphologie u. phys d. Pilze, Flechten und Myxomyceten— Proff. de Bary, in 

 Hofmeister's Handbuch dpr Phys. Bot., Bd. ii., p. 291. 



+ Currcy "On Freshwater Algae," in "Quart. Journ. of Micr. Sci.," vol. vi. 

 (1st ser.), page 216. 



