BOTANY. 515 



species above named, and was able to watch their develop- 

 ment and the effect produced by the growth of the liyphas 

 upon the free gonidia. In Endocarpon and Thelidium he 

 was able to follow the whole course of the development from 

 the germination of the spores until the ripening of new 

 spores. The most important result of Stahl's work was the 

 following : He took the spores of Theliclium minutulum and 

 the gonidia of Endocarpon pusiUum, and found that the 

 former grew as well upon the gonidia of the latter as upon 

 its own gonidia, and he Avas able to produce new asci and 

 spores of Thelidium when growing upon the foreign gonidia. 

 This is the first successful attempt at reproducing a perfect 

 lichen by sowing the spores, and strengthens, in a forcible 

 manner, the theory of Schwendener that lichens are fungi 

 parasitic upon certain alga?. Dr. Minks, in a paper in Elora, 

 "Das Microgonidium," gives a statement of his views of the 

 origin of gonidia in lichens, which are opposed to those of 

 Stahl. He thinks that if Stahl had made use of higher 

 powers of the microscope, he would have seen the same 

 structures as Dr. Minks himself. Exactly what those struct- 

 ures were it is rather difficult to understand from Dr. 

 Minks's paper, and no figures are given ; so that botanists 

 will hardly conclude that he has satisfactorily answered 

 Stahl's paper until the appearance of the memoir, of which 

 he states that the present paper is only a prodromus. Bor- 

 zi, in a careful paper which appeared in the Italian Journal 

 of Botany ^ in which he gives the result of his investigations 

 on the sexuality of the Ascomycetes, confirms the views of 

 Stahl with regard to the reproduction in lichens. Flora 

 contains a number of descriptive papers on lichens ; by 

 Krempelhuber, on Species Collected in the Argentine Repub- 

 lic; and Notes, by Nylander, on some European Lichens, and 

 on Lichens from the Desert of Sahara and from Corsica. 

 The Austrian Botanical Journal has a paper by Arnold on 

 Lichenological Excursions in the Tyrol ; and in the Journal 

 of the LinnaBan Society is a Description of some British 

 Lichens, by Leighton. 



Of the numerous contributions to our knowledge of alga? 

 may be mentioned, in the first place, the superb work of 

 Thuret and Bornet entitled "Etudes Phycologiques." This 

 is probably the mo^st elaborate and beautifully illustrated 



