284 H. MARSHALL WARD. 



lu Claviceps, the young perithecium arises as a mass of 

 small cells, which rapidly divide and form a parenchyma-like 

 mass. A hollow then appears in the interior (reminding one 

 in many respects of the cleavage cavity in some animal 

 embryos) by the separation of the cells. The mass now con- 

 sists of a thick basal portion, over which is a hollow space 

 roofed over in a dome-like manner by the upper cells. There 

 is no trace of an ascogonium or of " Woronin^s hyphse " at any 

 time; the asci arise by budding from the cells forming the floor 

 of the cavity. 



Cordiceps and other species of both genera agree in the 

 main with what has been described. 



In summing up the foregoing, the author points out that 

 while in Polystigma we have morphologically the same 

 organs as occur in the Collemacese (viz. spermatia, trichogyne 

 and ascogonium), no sexual process could be demonstrated. 

 In Xylaria the sexual organs — at any rate the ascogonium — 

 is represented morphologically, but has become functionless — 

 it deliquesces and is absorbed before the asci arise ; these 

 spring in a purely vegetative manner from the lining walls of 

 the perithecium. It is possible that certain facts observed in 

 Cucurbitaria point to the same end. 



In Claviceps the perithecium is purely apogamous — no trace 

 of an ascogonium occurs, and the asci are produced by a vegeta- 

 tive process of budding from the floor of the perithecium cavity. 



Putting together the foregoing facts, and what is known 

 otherwise of the allies of these Fungi, Fisch shows that the 

 compound Pyrenomycetes present a series of forms which 

 commence with a complete diff"erentiation of sexual organs 

 (ascogyne, trichogyne, and spermatia), and end in forms which 

 are quite apogamous, and with no trace of sexuality. We may 

 go further than this. 



Beginning with Podosphasra, in which a sexual process is 

 possibly still recognisable, we trace a series through the simple 

 Pyrenomycetes and the Discomy cetes branching ofi^ from 

 these, ending with the completely apogamous ChaBtomium^ 



1 Van Tiegliem, 'Compt. rend./ 1875 ; and 'Bull. Soc. Bot. Fr.,' ]876. 



