74 SUMMARY OF CURRENT RESEARCHES RELATING TO 



for a while, returned again, and repeated the process. The emptying of 

 a sporangium was watched, till two zoospores only were left ; these, 

 having failed to escape, put out a germ-tube some 15-20 /x long, which 

 penetrated the wall of the zoosporangium ; as it failed to find nourish- 

 ment the tube was withdrawn, the zoospore moved to the other side of 

 the sporangium and repeated the process, after which it degenerated. 

 Other species recorded are Rhizophidium sphserocarpum on Mougeotia 

 parvula, Rhizophidium minutum sp.n. on Spirogyra varians, Lagmidium 

 Rabenhorstii on Spirogyra sp. n., Lagmidium americanum sp.n. in zygo- 

 spores of Spiroyyra ; Phlyctochytrium planioorne sp. n. also on Spirogyra 

 varians, and Phlyctochytrium equate on Spirogyra insigne. A description 

 is given of these plants, their development, and the formation and 

 escape of the zoospores, with the effect on the host-plant. Five other 

 species are listed, which were studied only for identification. 



Cytology of the Ascus. — This subject has been investigated by 

 W. E. Brooks * and H. C. I. Fraser in three different Ascomycetes— 

 Humaria granulata, Ascobohtsfurfuraceus, and Lachnea stercorea. These 

 forms were selected, as in each of them fertilisation of a reduced type, 

 represented by fusion of nuclei in the ascogoninm, had been observed, 

 with a second fusion in the ascus. Methods of staining, etc., are 

 detailed. In the first of the fungi examined, four chromosomes were 

 observed in the ascogenous hyphre, but they were found to be four 

 bivalent chromosomes equivalent to the eight chromosomes of other 

 forms. In the three divisions in the ascus to form the eight spores, a 

 somewhat similar process was observable in the different fungi. The 

 first division was heterotypic ; the second division was homotypic, but a 

 second reduction took place at the third division. After brachymeiosis 

 was complete, there were four chromosomes in Humaria and Ascobolus, 

 and two in Lachnea. In the first ascus division of Lachnea two long 

 chromosomes and two short ones were constantly recognised ; after the 

 second reduction there was one long and one short, each type of 

 chromosome probably forming the physical basis of a different set of 

 characters. The writers discuss at some length the conjugation of the 

 premeiotic chromosomes to form the gemini of the heterotypic prophase ; 

 the formation of the spore membrane is touched on. 



Development of Monascus.t - - Schikorra designates the fungus 

 which he examined, Monascus x, a new species. He describes the 

 formation of conidia from the tips of the hyphae, while on other hyphte 

 were formed the antheridia and aseogonia with trichogynes. The 

 antheridium is cut off from the top of a hypha rich in contents, and is 

 always multinucleate; the cell beneath the' antheridium grows out and 

 forms an ascogonium with an upper cell, the trichogyne, both also 

 multinucleate ; copulation takes place between the trichogyne and 

 antheridium, the nuclei of the former degenerate while those of the latter 

 pass over through the trichogyne and penetrate the ascogonium, the 

 dividing wall partly breaking down. Fusion does not take place, but 



* Ann. Bot., xxiii. (1909) pp. 537-49 (2 pis.). 



t Zeitschr. Bot., 1. (1909) pp. 379-410 (1 pi.). See also Bot. Centralbl., cxi. 

 <1909) pp. 447-8. 



