206 FUNGI. 



patches of Penicillium were found to be intermixed with another 

 mould of a higher development, and far different character. 

 This mould, or rather Mucor, consists of erect branching 

 threads, many of the branches terminating in a delicate globose, 

 glassy head, or sporangium, containing numerous very minute 

 subglobose sporidia. This species was named Mucor liyalinus.* 

 The habit is very much like that of the Penicillium, but without 

 any roseate tint. It is almost certain that the Mucor could not 

 have been present when the Penicillium was examined, and the 

 leaves on which it had grown were enclosed in the tin box, but 

 that the Mucor afterwards appeared on the same leaves, some- 

 times from the same patches, and, as it would appear, from the 

 same mycelium. The great difference in the two species lies in 

 the fructification. In the Penicillium, the spores are naked, and 

 in moniliform threads ; whilst in Mucor the spores are enclosed 

 within globose membraneous heads or sporangia. Scarcely can 

 we doubt that the Mucor alluded to above, found thus intermixed, 

 under peculiar circumstances, with Penicillium roseum, is no other 

 than the higher and more complete form of that species, and 

 that the Penicillium is only its conidiiferous state. The pre- 

 sumption in this case is strong, and not so open to suspicion as it 

 would be did not analogy render it so extremely probable that 

 such is the case, apart from the fact of both forms springing 

 from the same mass of mycelium. In such minute and delicate 

 structures it is very difficult to manipulate the specimens so as 

 to arrive at positive evidence. If a filament of mycelium could 

 be isolated successfully, and a fertile thread, bearing the fruit of 

 each form, could be traced from the same individual mycelium 

 thread, the evidence would be conclusive. In default of such 

 conclusive evidence, we are compelled to rest with assumption 

 until further researches enable us to record the assumption as 

 fact.f 



Apropos of this very connection of Penicillium with Mucor, a 

 similar suspicion attaches to an instance noted by a wholly dis- 



* Specimens were published under this name in Cooke's " Fungi Britannici 

 Exsiceati," No. 359. 



t Cooke, "On Polymorphism in Fungi," in "Popular Science Review." 



