BOTANICAL GAZETTE. 206 



Lichen culture receives a due share of attention. In fact the 

 early researches of de Bary paved the way to the generalizations of 

 Schvvendener. Whatever view one may adopt as to the essential 

 nature of lichens, their culture is of great interest. The favorite 

 species for observation is Endocarpon pusillum, Hedwig. {Dermato- 

 carpon Schocreri. Koerher). These are collected in the late, autumn, 

 and enough of the clay removed with them to keep them alive in 

 healthy condition until required. No water must be gi'ven them until 

 they are taken for the cultures, otherwise the spores and small gonidia 

 coinained in the apothecia will be prematurely extruded " The spores 

 and gonidia are to be sown in a flowerpot dish, on clay which has 

 been thoroughly boiled, and then the surface made smooth as possible, 

 which makes it easier to detect the first sign of the growing lichen.' 

 The lichens are then taken along with the surrounding clay, nicely 

 bedded in sand and supports provided on which the edges of the in- 

 verted clay containing dish, may rest so that the surface of the moist 

 clay is about one fourth of an inch from the lichen. The lichens are 

 now sprinkled with water and the dish placed in position over them. 

 Spores and gonidia will be extruded in association, and after 24 hours 

 the dish may be removed and put under a bell glass in a light place 

 which IS not too damp nor too cold, i. e. temperature something above 

 freezing. While the dish is inverted it should be turned round a little 

 about every half hour to secure a distribution of the spores and gonidia 

 over the surface, and small bits of "cover glass" may be placed here 

 and there on the surface, which being removed will show under the 

 microscope if the spores are escaping properly. The growing s]jores 

 are handsome objects mounted in glycerine and quite instnictive 

 These may be obtained by placing the glass slip over the lichens as the 

 dish was placed, and afterwards setting it away in a moist place for a 

 few days. It is to be observed that if the dish on which the spores and 

 gonidia are sown be kept too moist and too warm at first, fungi will 

 probably injure the culture. For fuller particulars of the process the 

 reader is referred to Prof. Stahl's Paper, Beitrage zur Entwickel- 

 ungogeschichte der Fletchen. Heft. II ; ueber die Bedentung der 

 Hymenial gonidien. Leipsic, 1877. Arthur Felix. 



Fertusaria is also another favorite groiTp, the gonidia of which are 

 obtained by immersion of the brittle crustaceous mass in water, allow- 

 ing them tu multiply and form zoospores, and then placing them in as- 

 sociation with the spores. 



A plentiful supply of fresh water Algie is always on hand. These 

 are kept in glass jars, which stand in the windows and under cover of 

 a bit of glass. Of course the water is frequently changed, and so with 

 little trouble these may be observed in the various stages of growth 

 throughout the year. ' 



The above hastily written notes will suffice to give an outline as 

 to the modes of culture employed in the celebrated laboratory in Strass- 

 burg. Special inquiries demand special adaptations, and these will 

 readily enough suggest themselves to an observer. A noteworthy fea- 

 ture is the extreme care observed by Prof de Bary in keeping his 

 growing solutions free from foreign spores by boiling and if need be, 

 filtering before using. Boiled or distilled water is used for all ordina' 



