370 FUNGI 



protoplasm ; and this organ, instead of behaving passively in the opera- 

 tion, bends over till it touches the top of an adjoining antherid, to which 

 it adheres. When this has taken place, the trichogyne becomes separated 

 by a transverse septum at the base from the carpogone, and then, 

 through the dissolution of the intervening membrane, the contents of 

 trichogyne and antherid are mingled. After impregnation the carpogone 

 increases in volume, and from numerous points of its surface there are 

 emitted ascogenous hypha. From the sterile cells and the whole basal 

 region of the rosette, the envelope-hyphae now grow forth and form a 

 large stroma enclosing the carpogones and antherids the latter re- 

 maining almost unaltered, full of protoplasm, and taking no part in the 

 formation of the envelope and upon the stroma a free hypothece 

 bearing the paraphyses. In the production of asci and the farther 

 development of the apothece, Pyronema agrees with Ascobolus. 



Pyronema, like Ascobolus and Gymnoascus, produces no acrospores ;. 

 and sporocarp follows sporocarp without intervention on successive 

 thalli. 



7. SORDARIA (Ces. and de Not.) and MELANOSPORA (Corda), both 

 Pyrenomycetous forms, are placed next Ascobolus by de Bary with 

 respect to the morphology of their sporocarps of course excluding such 

 differences of form as are peculiar to their being Pyrenomycetes, while 

 Ascobolus is, as has been shown, a Discomycete. Fundamentally there 

 is little real difference in the mode of origin of the sporocarp ; and 

 Chaetomium and Ascotricha may eventually prove to belong to the same 

 series. 



8. COLLEMACE^E. In the Collemaceae, a group of discocarpous 

 lichens, the structure, development, and mode of behaviour of the male 

 sexual element is wholly different from any hitherto described, while 

 the carpogone remains of similar structure, though, of course, modified 

 to meet the requirements of the changed conditions. The male cells 

 are pollinoids formed in a flask-shaped antherid, somewhat resembling 

 a peiithece. It is sunk beneath the surface of the thallus, and opens 

 by means of a narrow neck. The flask consists of a wall of densely- 

 compacted hyphae, giving off towards the interior a layer of numerous 

 delicate hyphae (sterigmata), which converge towards the central portion 

 of the flask. These form at their apices successively in series numerous 

 pollinoids, which soon fill the central space. The pollinoids are thin- 

 walled rod-shaped cells, with an outer membrane of a gelatinous kind, 

 readily swelling and dissolving in water. In damp rainy weather water 

 gets access to the pollinoids, and through the swelling action mentioned 

 they are forced out through the neck of the antherid and dispersed 

 over the surface of the thallus. The development of the antherid 



