M. C. COOKE ON CIRCUMNUTATION OF FUNGI. 311 



and produce a profuse mycelium, the above results set me to watch 

 the germination of spores of the common mould Penicillium 

 glaucum, and I had soon thirty or forty slides well covered with 

 the germinating filaments of this mould, the growing points of the 

 main shoots and branches circumnutating in a beautiful manner, 

 forming spirals about '012mm. in diameter, with six turns, or there- 

 about, to the one-tenth of a millimetre. Soon after germination 

 the circumnutation commenced, branches were thrown off at inter- 

 vals on either side, and these convoluted spirally in the same 

 manner as the main thread. These branches seemed destined to 

 steady, or hold the thread firmly, motion having ceased in the 

 thread except near the extremities of the axis or its branchlets. 

 Here and there short erect straight branches arose which bore at 

 their apex the characteristic chains of spores. These did not 

 exhibit any kind of perceptible motion and hence were not convo- 

 luted. All these examples were growing in a moist atmosphere, 

 but not in water, the threads soon extended beyond the small drop 

 of fluid in which they first germinated, and circumnutated in the 

 air of the cell. 



These results prove, therefore, incontestibly, that the spiral 

 habit of the germinating threads of the spores is not a phenomenon 

 confined to the Uredines, but is as active in the Mucedines, and 

 probably in the majority of fungi, with some modifications, as in 

 flowering plants. Hitherto my object has been simply to ascertain 

 the fact of circumnutation, and hence no effort has been made to 

 determine the direction of the spiral, the rate of growth, or of 

 movement, or the influence of light, but I have no doubt that most 

 interesting results would accrue from a systematic series of obser- 

 vations, such as those already made with climbing plants. 



Plate IX. figs, a and c germinating spores of Uredo linearis ; figs. 6 and 

 d germinating spores of JEeidium tussilaginis, after Plowright ; fig. e germ 

 filaments of Penicillium glaucum. 



