309 



ClRCUMNUTATION IN FUNGI. 



By M. C. Cooke, M.A., A.L.S., President. 



{Read August 24th, 1883.) 



PLATE IX. 



Members need not to be reminded that the late Dr. Charles Dar- 

 win demonstrated most elaborately in his works on " Climbing 

 Plants " and the " Movements of Plants " certain movements so 

 common in flowering plants, under various modifications, which he 

 terms " circumnutation. " This kind of movement has not been 

 much observed, or, if observed not yet recorded, in the lower 

 Cryptogamia, and yet it is an undoubted fact that such move- 

 ments appear to be as general amongst the Cryptogamia as 

 amongst the higher orders of plants. The conditions under which 

 it has been observed hitherto is in the growing mycelium, or 

 germinating threads which emanate from spores in favourable 

 conditions, and these represent in miniature what ordinarily takes 

 place in climbing plants, viz., a continual movement from side to 

 side, forming a spiral round an imaginary axis, that highly 

 developed form of circumnutation which is to be seen illustrated in 

 the hop. 



A writer in " Grevillea " * lately described this movement in 

 the mycelioid threads of several of the Uredines, from which it is 

 clear that he is of opinion, not that it was an exceptional case, but 

 a constant phenomenon, which he failed to estimate at the import- 

 ance it deserved. He says " when the spores of Uredo linearis, 

 which are more or less ovoid in form, are sown upon a drop of 

 water on a glass slide and placed under a bell glass, so arranged 

 that the atmosphere within the bell glass is full of moisture, they 

 very soon begin to germinate. As early as five hours and forty 

 minutes they were found to have thrown out two germ tubes, one 

 from each side of the long diameter of the spore near its centre. 

 Sometimes only one tube was observed, but generally there were 



* Vol. x , p. 136. 

 Journ. Q. M. C, Series II., No. 7. B b 



