88 SUMMARY OF GUERENT RESEARCHES RELATING TO 



Lichens. 

 ; (By A. LoRRAiN Smith.) 



Lichen Ecology in Thuringia.* — G. Lettau describes the species of 

 lichens in their various habitats in and near Thuringia. The lichen flora, 

 iike other plant floras, depends on the geological and climatic conditions 

 of the districts, and is liable to serious disturbance of human interference 

 with the ground, forests, etc., the number of species and of individuals 

 being seriously lessened by the encroachment of agriculture, etc. The 

 author discusses the relative heights of the uplands and the amount of 

 rainfall and of the prevailing moisture. The Trias formation is well re- 

 presented, and the rocks composing it are apt to be broken up so that often 

 any lichen growth is unable to persist. There is an absence of streams, 

 so the hygrophilous lichens are absent, and only the xerophilous forms 

 grow in abundance ; silicicolous lichens are also wanting in the district. 

 Lists are given of the lichens found on the different rocks, soils, etc., 

 as well as of those found on trees, timber, etc. 



Biology and Ecology of Epilithic Lichens. f — E. Malinowski has 

 made a study of the growth of crustaceous lichens on rocks. He noticed 

 that on rocks newly exposed — granite and quartzose — the number of 

 species is at first few. They gradually increase to a certain maximum 

 number, and then begin to decline : the decline being due to the 

 vigorous growth of some of the lichens, which gradually displace those 

 of slower development. Malinowski explains the different ways in which 

 these crustaceous lichens spread over the rocks, the formation of cracks 

 and fissures, the disintegration of the thallus, and the regeneration of 

 species. He gives lists of the lichens as they appear, and of those that 

 are finally victorious in the struggle for a foothold. He concludes with 

 a descriptive list of the lichens alluded to by him in the course of the 

 work. 



Mycetozoa. 



(By A. LoRRAiN Smith.) 



Myxomycetes from the Forest of Fontainebleau.| — S. Buchet 

 remarks on the comparatively few records of Mycetozoa in France ; he 

 publishes a list of the species collected by him during short excursions 

 in three years. Many of the species he found only once, and that in 

 the near neighbourhood of the forest laboratory, so probably a more 

 careful search would have resulted in many more records. Buchet 

 reports fifty-one species ; be gives the habitat in each case. 



Ledoux-Lebard — Flore des Myxomycetes. (French Myxomycetes.) 

 [A conticuation of the lists begun in a previous paper.] 



Bull. Soc. Mycol. France, xxvii. (1911) pp. 303-27. 



* Hedwigia, li. (1911) pp. 176-208. 



t Bull. Acad. Sci. Cracovie (1911) pp. 849-90 (1 pi. and 6 figs.). 



X Rev. G6n. Bot., xxiii. (1911) pp. 409-17. 



