GAPING FUNGI— HYSTERIACEAE 225 



on living bark, aggregated in dense patches, and the perithecia 

 are elliptical and irregular. A condition may often be met 

 with in which no asci are developed, but these are replaced by 

 stylospores. This condition has been referred to Sphaeroiosideac, 

 under the generic name of Psilospora, whilst other authors 

 simply mention it as the pyc7iidia of Dichaena. There is little 

 doubt of its being an imperfect condition of this Hysteriaceous 

 genus. The section Hyalodidyae includes the one genus 

 Gloniopsis, in which the sporidia are muriform but hyaline. 

 The habit and texture is that of Hystermm. In the same 

 manner, species of the old genus Hysterium which have muriform 

 coloured sporidia find a place in the section Phaeodictyae under 

 the genvis Hystcrograplimm,. The ninth section is Scolecospoixic, 

 in which the sporidia are very much elongated, so as to be 

 thread-like, or rod-like, and hyaline. The one genus in which 

 the sporidia are cylindrical, and much shorter than the asci, is 

 Hypoderma. The perithecia are membranaceous, and flattened, 

 with a narrow fissure, and the species are most commonly 

 found on dead leaves, herbaceous stems, and occasionally on 

 young twigs. Sometimes several perithecia grow on irregular 

 bleached spots, and these are often accompanied by smaller 

 perithecia, which contain only minute stylospores, belonging 

 technically to the Sphaeropsideous genus Leptostroma, but which 

 are often called the spermogonia of the various species of 

 Hypoderma. It must not be assumed that the term spermatia, 

 applied to the minute bodies enclosed in the smaller perithecia, 

 indicates fecundative functions, since no sexuality has been 

 proved. In the remaining genera the sporidia are truly filiform. 

 Lopliodermiuin has the habit and appearance of Hypoderma, 

 but the sporidia are different, and in like manner the species 

 are often associated with forms of Leptostroma. Lophium is 

 a small genus with rather carbonaceous perithecia of a shell- 

 shape, as mentioned under Mytilinidion, with very acute con- 

 nivent lips. Sporomega has depressed, and rather coriaceous, 

 perithecia, with thick gaping lips, which partially expose the 

 disc (Fig. 103); and Golpoma resembles it in these features, 

 but differs in being developed beneath the cuticle, which is for 

 a long time adpressed, or adherent to the lips, and the substance 

 is softer. In habit it resembles TryUidiuvi rather than 



15 



