M. C. COOKE ON NETTLE STEMS AND THEIR MICRO-FUNGI. 



73 



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Fisr. 3. 



side by side, and expand at the apex 

 into a head or tuft of large, somewhat 

 elliptic spores. These spores are divided 

 unequally by transverse septa, the central 

 portion being coloured brown, and the ex- 

 tremities colourless. By a little careful 

 manipulation this mould may be examined 

 in situ, although when such a high power 

 as a third or a quarter-inch objective is 

 required for an opaque object patience and 

 perseverance are requisite. We have found 

 that a third with a small nozzle, bevelled at the edge, on the conti- 

 nental rather than the English method of mounting the lenses, is the 

 most effective. Such an objective admits of more light being thrown 

 down upon the mould by means of a bull's eye and side reflectors 

 than can be accomplished with the usual English objectives. With- 

 out intending any invidious allusion to one maker rather than 

 another, we may be permitted to state that such an objective was 

 made for us on the abcve plan by Mr. Swift, at a moderate price, 

 and has succeeded better than any other plan we have adopted to 

 secure the examination of such opaque objects as moulds, and other 

 microscopic fungi, in their natural condition, by means of high 

 powers. Doubtless the lime light recommended by Mr. Green for 

 the examination of diatoms would be a valuable adjunct, although 

 we cannot as yet speak from experience. It cannot be urged too 

 often or too strongly that, in order to see objects as they really are, 

 they should be viewed by the opaque method, and not by having 

 the light thrown through them. To confide in such a mode as 

 the latter may save trouble, but it is only a delusion and a snare. 

 Another black mould found by Mr. Broome, 

 on the old stems of tlie nettle, is Acrothecium 

 simplex. In this genus the jointed threads are 

 either simple or branched, with the spores clus- 

 tered at the apex (fig. 4). In the present species 

 the threads are simple and flexuous, bearing a few 

 almost clavate spores at the apex. The threads 

 are brown, and the spores slightly coloured, 

 divided transversely by four or five septa. Mr. 

 Broome found this species in the month of De- 

 cember, and as there is no other record of it, pro- 



