450 SUMMARY OF CURRENT RESEARCHES RELATING TO 



habitat alone. On the same specimen he has found both yellow and 

 white medullary hypha), and sorediate and non-sorediate lobes. In this 

 judgement he differs from Nylander, Crombie and others. He records 

 altogether eighty species on stones, seventeen on the soil, and fifty-five 

 on trees. 



Protection of Lichens against Animals.* — E. Stahl finds that the 

 protective substances elaborated by lichens are the lichen acids, especially 

 vulpin acid. Not only do these acids ward off snails, caterpillars, etc., 

 but they prevent the development of bacteria, as they have antiseptic 

 properties. He found, however, that their presence does not affect the 

 growth of filamentous fungi. 



Lichens as Endosaprophytes.f — A. Elenkin has examined a number 

 of heteromerous lichens in the Lecidese, Acarosporese and Endocarpeas, 

 to determine the relation between the fungi and algas constituting the 

 lichen plant. In many of the specimens he finds layers of dead gonidia 

 {nelcrale zone). In Lecidia atro-brunnea he noted the outgrowths of 

 fungus hyphae piercing the Pleurococcus gonidia, which in this case are 

 very large. These outgrowths are similar to the haustoria described by 

 Schneider and Peirce, but the author considers that they destroy the 

 algse rather than that they live in symbiotic union with them. 



Arcangeli, A. — Sulla struttura dell' TTsnea articulata. (On the structure of Usnea 

 articulata.) 



[The writer describes the vegetative structure in great detail. He concludes 

 that U. articulata is only a variety of U. barbata.] 



Atta. Soc. Jose. Sci. Nat., xiv. (1904) pp. 46-52. 

 Zahlbeuckner, A. — Neue Flechten. 



[Diagnoses of six new species from Trieste, Java, Australia and Nicaragua.] 



Ann. Mycol, ii. (19'J4) pp. 267-70. 



Mycetozoa. 



Studies of Mxyomycetes.J — E. Jahn gives the results of observations 

 on nuclear division in the formation of the cilium in the swarm-spores 

 of Stemonitis flaccida. The cilia, he finds, grow out from the poles of 

 the nucleus ; their earliest development coincides with the beginning of 

 the cell-division. They increase slowly, and have hardly attained full 

 growth when the nucleus is fully formed. At the base of the cilia are 

 strongly staining granules, which are identical with the centrosomes of 

 the spindle. Jahn discusses the nature and function of these granules, 

 comparing them with those found in other nuclei. He also gives a 

 minute account of the stages of nuclear division observed by him in the 

 swarm-spores. 



Schizophyta. 



Schizophyceae. 



Studies on Cyanophycese. — F. E. Fritsch publishes the first of a 

 series of papers under this title. The present communication deals with 



* Festsch. siehzigst. Geburtst., von Ernst Haeckel, Jena, G. Fischer, 1904, 

 pp. 353-76. See also Ber. Deutsch. Bot. Gesell., xliii. (1904) p. 55. 



f Bull. Jardin Imp. Bot. St. Petersb., iv. (1904) pp. 25-39 (2 pis. and 4 figs.). 

 See also Ber. Deutsch. Bot. Gesell., xxii. (1904) pp. 54-5. 



\ Ber. Deutsch. Bot. Gesell., xxii. (1904) pp. 84-92 (1 pi.). 



§ New Phytologist, iii. (1904) pp. 85-96 (figs, in text.). 



