684 SUMMART OF CURRENT RESEARCHES RELATING TO 



Howe, 11. Hebbb — The Genus Evernia as represented in North and Middle 



America. 



[The genus is divided into the sections Lethcuria, 

 Archeverrtia, and Euevemia; the latter with 

 one species, E. trulla.] 



Bot. Gaz., li. (1911) pp. 431-42 (2 pis.). 

 ,, ,, List of Lichens collected in the Yukon Region by R. S. 



Williams. 



[Eighty-two species are listed.] 



Bull. Torrey Bot. Club, xxxviii. (1911) 



pp. 287-93. 

 L ksdain, Bouly de — Lichens Beiges rares ou nouveaux. (List of crustaceous 

 lichens new to Belgium or rare.) 



Bull. Soc. Roy. Bot. Belg., xlvii. (1910) pp. 39-45. 

 Olivier, H. — Lichens d'Europe. II. 



[305 species are recorded in this fascicle ; synonymy, locality, and habitat 

 are given, with keys to genera and species, and with index.] 



M&m. Soc. Nat. Sci. Nat. Math. Cherbourg, xxxvii. 



(1908-10) pp. 29-200. 

 Steinee, Julius — Adnotationes lichenographicae. 



[New species and new varieties of lichens are described 

 from various localities.] 



Oesterr. bot. Zeitschr., 1911, Nos. 5, 6 (8 pp.). 

 ,, ,, Flechten aus dem italienische-franzbsischen Grenz' gebiete 



and aus Mittelitalien. (Lichens from the borderland be- 

 tween France and Italy and from Central Italy.) 



[A large number of species are listed, including many 

 new species ] 



Verh. k.k. Zool. Bot. Ges. Wien, 1911, 



pp. 29-64. 

 Zahlbbucknee, Alexander — Transbaikalische Lichenen. (Lichens from 

 beyond L. Baikal.) 



Trav. Sous. Sect. Troitzk.-Eiakhta, Section du pays d'amour 

 Soc. Imp. Russe de Geogr., xii. Liv. 1-2 (1909) pp. 73-95. 



Mycetozoa. 



(By A. Lorrain Smith, F.L.S.) 



Studies in Myxomycetes.* — E. Jahn has made many spore cultures 

 and studies of plasniodium to determine the occurrence of sexuality in 

 the Myxomycetes. He states that in many species plasmodium forma- 

 tion can be observed. As soon as ciliated spores are formed he advises 

 drying, when these become encysted, and with renewed wetting they 

 divide ; this can be repeated several times. The species most easily 

 dealt with were Stemonitis fusca, Trichia varia, Oligonema ?iitens f 

 Physarum nutans, P. compressum, and P. didermokles. Jahn sums up 

 his results thus : 1. Plasmodium formation begins among numerous 

 amoeba? at certain points with small amoebfe-like stages. 2. These 

 young plasmodia exercise no attractive influence on surrounding arnoebse ; 

 they devour them when they encounter them. 3. Nuclear increase 

 follows also from the earliest stages in normal development of karyo- 

 kinesis. 4. In young plasmodia with normal development the numbers 

 of nuclei are always even ; uneven numbers are very rare. 5. Plasmodia 

 nuclei have the double chromosome number of the amoeba? nuclei. 6. 

 An amoeboid and nuclear copulation could be seen. 7. Nuclear division 

 before spore-formation is a reduction division. 



* Ber. Deutsch. Bot. Gesell., xxix. (1911) pp. 231-47 (1 pi.). 



