ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 427 



already recorded tended to prove that the mildew on one genus of cereals 

 would not pass over to another — that there were, therefore, distinct 

 biological forms. He has now estaljlished the further fact that none of 

 the cereals can be infected by the fungus taken from other grasses. 

 E. graminis is specialized on each of the different host genera. It has 

 been further found that species of one genus of host-plant may be liable 

 to attack, while others are immune. Details of experiments are given, 

 and comparison is made with Steiner's work on the powdery mildew of 

 Alchemilla, Sphserotheca HumuU. 



Cytology of Laboulbeniacese.* — ^J. H. Faull has made a study of 

 two species, and describes the cell-structure, nuclear divisions, etc. No 

 antheridia were found in the species L. chsetophora and L. gyrinidarum. 

 The development of the procarp has been studied. It consists of a 

 uninucleate carpogonium, a uninucleate trichophoric cell, and a branched 

 and septate trichogyne, each cell of which is a monoenergid. The carpo- 

 gonic and trichophoric cells become continuous, and the former becomes 

 bi-nucleate, probably from division of the nucleus. At a later stage these 

 nuclei divide and a daughter-nucleus from each pair passes into an ascus, 

 which has budded out. No fusion of nuclei was observed until the two 

 nuclei in the ascus fused. The fusion nucleus then divides meiotically. 

 The number of chromosomes is the same as in other mitoses. Subse- 

 quent divisions are homotypic. Eight nuclei are produced, but only 

 four are functional in spore formation. 



Iowa Discomycetes.f — F. J. Seaver now publishes a complete account 

 of the Discomycetes of the State. Keys are supplied to families, genera, 

 and species, and descriptive accounts of the plants are given, especially 

 the microscopic details. There are fifty-six genera represented in this 

 list, only one of which, Holivaya, is exclusively American, the others are 

 all common European genera. A full bibliography is given of books 

 and papers bearing on the subject. 



Study of Ascobolacese.:!: — Bernard 0. Dodge has studied all the 

 published methods of securing spore-germination in fungi and the sub- 

 sequent cultures. He gives a summary of results. In many of them 

 heat is the most important factor in inducing growth. Special atten- 

 tion was directed to the development of Ascobolus carbonarius ; the 

 mycelium produces a large number of conidia, some of which give rise 

 directly to the archicarp. The latter consists of the preliminary or stalk 

 coil, the ascogonium and the trichogyne. The tip of the trichogyne 

 sometimes becomes coiled about an antheridial conidium. Archicarps may 

 also arise from the mycehum, and in some species they do so constantly. 



The general characters of the archicarps described and the presence 

 of septate trichogynes support the view that the lichens represent primi- 

 tive forms of the Ascomycetes. 



Lancashire Ascomycetes. §— Harold J. Wheldon publishes a list of 

 species, most of them collected in recent years in connexion with work 



* Ann. Bot., xxvi. (1912) pp. 325-65. 

 t Bull. State Univ. Iowa, vi. 2 (1911) pp. 41-63 (41 pis.). 

 I Bull. Torrey Bot. Club, xxxix. (1912) pp. 139-97 (6 pis). 

 § Journ. Bot., 1. (1912) pp. 182-93. 



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