704 SUMMARY OF CUKRKNT RESEARCHES RELATING TO 



HoYT, W. D. — Periodicity in the Production of the Sexual Cells of Dictyota 

 dichotoma. Johns Hopkins Univ. Calendar, Notes Biol. Lab., 



March 1907, pp. 25-8 (2 charts). 



Kniep, H. — Beitrage zur Keimungs-Physiologie und -Biologic von Fucus. (Con- 

 tributions concerning the physiology and biology of the germination of Fucus.) 

 Pringsheim's Jahrb. Wiss. Bot., xliv. (1907) pp. 635-724. 



Quelle, F. — Bemerkungen iiber den inneren Bau einiger Susswasser-Diatomeen. 

 (Remarks on the inner structure of certain fresh-water diatoms.) 



[Several species have been exarained by the author, among them Nitzschia 

 amphioxys, N. sigmoidea, and Cylindrotheca Gerstenbergeri, which are 

 figured.] Mitth. Thilring. Bot. Verein., 1907, pp. 25-31. 



Fungi. 

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



Notes on Mucorini.* — A. Henneckel has made some observations 

 on the histology of the Mucoracese. He claims to have observed true 

 karyokinesis. Also in the chlamydospores of Mucor racemosus he has 

 observed nuclear fusion ; at first the cell contained 10-12 nuclei, which 

 gradually fused and became one large nucleus. 



The same author,t along with Tschernjajew, has experimented on 

 metallotropism in Phycomyces nitens. They found that copper was 

 repellent, while iron and aluminium were attractive. 



A. Lendner % writes on the different substrata in which Mucorini 

 may be found, and he gives an account of the different locahties where 

 he has collected these fungi from the plains to the summit of Mont 

 Blanc. He gives diagnoses of three new species. 



Review of Phycomycetes.§ — G, W. Wilson takes up the various 

 genera that have been included in the Peronosporales, and gives an 

 account of each, its origin and present position in the order. He 

 indicates those genera which are imperfectly described, or of which the 

 names ought to be dropped in favour of an earlier nomenclature. 



Pythium.ll — E. J. Butler has published a monograph of this genus 

 of fungi, with an account of some Chytridiacea. All the species of 

 Pythium are capable of saprophytic life, though a few are also parasitic. 

 The author considers that the conidia arose from the zoosporangia ; he 

 thinks also that the passage from sexual to asexual fructification took 

 place early in the history of the plants, before they had branched oft 

 from the Algae. Butler treats in the second part, the Chytridiacese that 

 are parasitic on Pythium. He describes several new species. 



Clithris quercina.^ — F. W. Neger and W. Dawson have made a 

 careful study of this fungus, which is very common on dead or dying 



* Scripta Bot. Hort. Univ. Imp. Petropol. xxiii. (1906) pp. 124-32 (6 figs.). 



t Tom. cit., pp. 115-23 (6 fig.). See also Ann. Mycol., v. (1907) p. 310. 



i Bull. Herb. Boissier, ser. 2, vii. (1907) pp. 249-51. See also Bot. Centralbl,, 

 cv. (1907) p. 277. 



§ Journ. Mycol., xiii. (1907) pp. 205-9. 



II Mem. Dept. Agric. India. Botany, ser. 1, No. 5 (1907) 160 pp., 10 pis. 

 See also Ann. Mycol., v. (1907) pp. 288-9. 



1 Ann. Mycol., v. (1907) pp. 214-20 (2 figs.). 



