1918] TEHON—CLITHRIS 553 
surprising, therefore, that the position of Clithris has been ques- 
tioned. That these superficial characters are not sufficient for a 
full diagnosis of relationship becomes at once evident, and the 
need of an exact statement is obvious. 
In making the present study, there have been available authen- 
tic specimens of Clithris quercina (Pers.) Rehm (Fungi Selecti 
Exsiccati, Rowmeguére, no. 268, and Mycotheca Universalis, De 
Thumen, no. 369); C. verrucosum Wallr. (Fungi Selecti Exsiccati, 
Roumeguére, no. 2827); C. andromedae (Schwein) Lindau (North 
American Fungi, Ellis, no. 155); and, through the kindness of 
E. A. Burt of the Missouri Botanical Gardens, C. crispa (Pers.) 
Rehm (Romell, Fungi Exsiccati Praesertim Scandinavici, no. 85). 
In addition to these, use has been made of the new species described 
in this paper. 
Material from all of these specimens has been sectioned and 
studied, and camera lucida drawings made of such as are not 
already illustrated. An examination of sectioned and unsectioned 
ascomata showed the following: 
1. The fruiting disk is large and of dicks crowded asci and 
paraphyses (figs. 3, 6; 8-11). This is a thoroughly Phacidiaceous 
character, distinct from Hysteriaceous forms, where the fruiting 
disk is small and seldom with asci and paraphyses overcrowded. 
2. The ascigerous hymenium is characteristically Discomyce- 
tous in nature (figs. 3, 6, 8-11). The Hysteriales are regarded as 
forming a bridge between the Discomycetes and the Pyrenomycetes; 
and consequently the more disklike the hymenium the less relation- 
ship the form may be expected to bear toward the Hysteriales. 
3. The opening of the ascoma is a true split (figs. 8-10). Its 
edges are jagged and torn; it is wider at some places than at others; 
and portions of the edges are frequently broken completely away 
in the tearing (figs. 2, 11). Opposed to this character is the rather 
regular appearance of the edges of the openings in Hysteriaceous 
forms which suggests that the slit there is an elongated ostiole 
rather than a true split or tear. 
4. The tendency in the specimens examined is to find the 
fruiting disk in places rather widely exposed, either by the wide 
bending back of the sides of the ascoma (figs. 3, 10) or by the 
