456 BRITISH FUNCil 



]\Ielanogaster 

 No sterile base present, and, as denoted by the generic name, 

 the gleba is usually' blackish or, at all events, quite dark-coloured 

 at maturity. The cells of the gleba are quite small at the peri- 

 phery, and gradually increase in size towards the centre of the 

 gleba. Some species are very strong-scented. Many branching 

 fibres spring from various points of the peridium. 



Rhizopogon 

 Sterile base absent. The surface of the peridium is traversed 

 by branched, rooting fibres or strands of mycelium which mostly 

 remain adnate or attached to the wall of the peridium throughout 

 the greater portion of their length. These strands originate from 

 the mass of vegetative mycelium upon which the peridia or fruiting- 

 bodies of the fungus rest. The cavities of the gleba are empty at 

 first ; that is, until they become filled with spores produced on the 

 surface of the walls enclosing the cavities. 



Hysterangium 

 No sterile base present. A feature of the present genus is that 

 in an early stage of development the consistency of the gleba is 

 more or less mucilaginous, and the entire fungus closely resembles 

 the undeveloped or " egg " condition of Mutinus caninus. The 

 peridia are seated on a copious development of white mycelium. 



OCTAVIANIA 



Peridium continuous or becoming cracked, but not perforated, 

 with a well-developed sterile base, externally cottony ; trama 

 readily splitting into two layers ; cavities at first empty, peripheral 

 ones small and more or less circular, becoming larger and irregular 

 in form towards the centre ; spores coloured, rough. 



Differs from Hydnanghim by the presence of a distinct sterile 

 lase, and from Melanogaster in the cavities of the gleba being 

 empt}^ at first, and in the byssoid nature of the tramal plates sur- 

 rounding the cavities in the gleba. 



0. asterosperma. — Peridium subglobose or irregular in form, 

 dirty white, becoming stained here and there with greenish blue 

 or black, sterile base thickish ; cells irregular in form, the central 

 ones largest, |-ij in. across ; spores glolose, coarsely echinulate, 

 14-15 /'. diam. 



Peridium globose or irregular, mycelium abundant, attached to 

 twigs and leaves underground, wall of peridium continuous or 

 cracked into areas, downy, whitish, becoming greenish blue or 

 black when bruised and exposed to the air. 



Underground amongst rotten twigs, leaves, etc. 



