628 SUMMARY OF CURRENT RESEARCHES RELATING TO 



number of plants. He gives helpful notes on many of the species, 

 summing them up in many instances into easily distinguishable 

 groups. 



Lichen Cephalodia.* — L'Abbe Hue has found, on examining Par- 

 melia cozcophora, from Chili, that there were two plants included under 

 the same name, like each other in outward appearances, but differing in 

 the fruit. The one has rather small apothecia, with colourless three- 

 celled spores; the other has larger fruits and large simple spores. Hue 

 found, on these Lichens, cephalodia which contained bright green alga? 

 associated with the blue-green. In one case the alga was a Glceocystis, 

 in the other Urococcus. All other recorded forms of cephalodia contain 

 blue-green alga3 alone. 



Polymorphism of Evernia furfuracea.f — A. Elenkin declares him- 

 self to be fully in accord with Zopf, Xylander, and Wainio as to the 

 importance of purely chemical characters in Lichens. He considers that 

 such characters are sufficient to differentiate species even when there is 

 no morphological distinction. One condition, however, is necessary, 

 that the reaction from the chemical test should be constant. He applies 

 this to the examination of Evernia furfuracea, divided by Zopf into five 

 chemical species, without morphologically distinct characters. In 

 hundreds of his specimens he found olivetor acid, which, according to 

 Zopf, is found only in Evernia olivetorina. In other specimens of 

 Scobicina type, he found furfuracin, which is confined to E. isidiophora. 

 These results, and also the fact that olivetor acid was found in very 

 varying quantities, have led Elenkin to consider Zopf's species, E.fur- 

 furacea, E. isidiophora, E. ceratea, and E. olivetorina, as one and the same 

 species. E. soralifera, he thinks, may perhaps be distinct from the 

 others. 



Lichenology for Beginners.^ — F. Le Roy Sargent publishes the 

 second of a series of papers intended as an introduction to the field 

 study of Lichens. He selects a common form of Parmelia, and instructs 

 the student as to the meaning of the terms used in describing such a 

 Lichen, and he also explains the structure and function of the thallus 

 and fruit. 



In another paper, by Bruce Fink§ on similar lines, the macroscopic 

 characters of the Lichen are chiefly dealt with — the different forms of 

 thallus that exist in this group of plants, their size, colour, and texture. 

 He emphasises the various points that are constant, and that have a 

 bearing on classification. 



An elementary guide to Lichenology, || accompanied by typical 

 specimens of the plants, has recently been issued by Abbe Harmand, 

 with the help of H. and V. Claudel. Their aim is to enable the 

 beginner to indentify the Lichens that occur most frequently. The 



* Ann. Assoc. Nat. Levallois-Perret, 1904," pp. 31-41. See also Bot. Centralbl., 

 xcix. (1905) pp. 34-5. 



t Bull. Jard. Imp. bot. St. Petersburg, v. (1905) p. 9-22. (Russian.) See also 

 Hedwigia, xliv. (1905) pp. 151-2. 



X Bryologist, viii. (1905) pp. 66-9 (5 figs.). § Tom. cit., pp. 73-6. 



U Epinal, 1904, 106 pp., 1 pi. See also Bot. Centralbl., xcix.(1905) pp. 68-9. 



