29 i INTRODUCTION TO CEYPTOGAMIC BOTANY. 



II. Physomycetes, Berk. 



Fertile cells bladder shaped, scattered on the threads, which 

 are not compacted so as to form a distinct hymenium. 

 Sporidia indefinite, formed from the protoplasm of the cells. 



308. This small but curious order is exactly intermediate 

 between Ascomycetes and Hyphomycetes. It agrees with the 

 former in the free development of its sporidia within a closed 

 sac, though this sac is more globular than in the more typical 

 species of that order. With the latter it agrees in the free 

 fertUe threads, which are peculiarly delicate and never com- 

 pacted, so as to form an hymenium. It is to be observed, 

 however, that in Acrostalagmus, which appears to be a 

 secondary form of TrichotheciuTn, or rather DactyUum,, the 

 reproductive bodies grow from the apex of the peduncle, which 

 protrudes into the cyst, a circumstance which might be fatal 

 to the separation of these Fungi under a distinct head, were 

 there not other instances in which a sac incloses true spores, 

 as, for example, in Badhamia and Enerthenema, amongst the 

 minute puff balls, and also in a species of Hymenogaster* 

 one of the hymeniferous truffles. If the point could be 

 established, that the same structure prevails in such genera as 

 Mucor and Ascophora, the order would, doubtless, merge into 

 Hyphomycetes ; but there is no evidence to this effect, though 

 in many cases a distinct columella, the tip of the fertile thread, 

 projects into the vesicle. 



309. Species occur probably in almost all parts of the world 

 on decajdng or decomposing vegetable matter, but few exotic 

 forms exist in our Herbaria, as they are often neglected by 

 travellers, and are preserved with difiiculty wherever the 

 atmosphere is moist, being pecuKarly hable to be attacked by 

 mites. A species of Mucor was collected in Cuba, by Ramon 

 de la Sagra ; several genera were found by Martius, in Brazil ; 

 and I have many species from the hotter parts of the United 

 States. No species appears in the Floras of the Antarctic 

 regions and New Zealand, but I do not doubt their existence 



* See Tulasne, Champignons Hypoges, tab. x., fig. 1, under Ili/meno- 

 gaster tener. The same curious appearance has been seen also by 

 myself and Mr. Thwaites. 



