CHAPTER V. COMPARATIVE REVIEW. ASCOMYCETES. 



241 



of the jelly, and which must necessarily be communicated to such small and light 

 bodies. 



With these characteristics the spermatia cannot be certainly distinguished from 

 small spores. The distinction however is, that, like those of Collema or Polystigma, 

 they are all, as far as has been hitherto observed, incapable of germination. 



Secondly, these organs all agree in having the spermatiophores collected together 

 into close hymenia in the spermogonia. These spermogonia are usually, as in Collema 

 and Polystigma, hollow receptacles like perithecia sunk in the tissue of the thallus, 

 with the cavity smooth and pitcher-shaped, or, as is very often the case, repeatedly 

 and very irregularly folded into sinuous depressions and projections, so that where the 

 folds are narrow the receptacle has the appearance in section of being divided into a 



FIG. 114. Diatrype qitercina, Fr. a a spermogonium on a piece of bark, laid open by removing 

 the periderm. The conically pointed upper surface which is folded in coils bears the hymenium of 

 the spermatia. * vertical longitudinal section through a spermogonium ; a tendril-like mass of sper- 

 matia is issuing from an opening in the overlying periderm. e fragment of a thin section through 

 the surface of the spermogonium with sickle-shaped spermatia and their sterigmata. After Tulasne. 

 a and b slightly magnified, c magn. 360 times. 



number of compartments. The cavity is everywhere lined with the hymenium which pro- 

 duces the spermatia, and the spermatia when mature are imbedded in jelly and occupy 

 the centre of the cavity, and when the jelly swells in water they issue crowded together 

 in drops or long strings from the narrow orifice of the spermogonium (Figs. 112, 113). 

 Some Pyrenomycetes which live in the rind of trees form layers agreeing in 

 every respect with the spermatiophores, except that they are not inclosed in receptacles 

 altogether belonging to the Fungus ; on the contrary they are disk-shaped or cushion- 

 shaped bodies with the spermatiogenous surface folded into deep sinuous depressions, as 

 in species of Diatrype (Fig. 114), Quaternaria, and Stictosphaeria, Tul., or else smooth 

 as in Calosphaeria princeps, Tul., and in both cases covered only by the peripheral 

 layers of the rind. The spermalia escape through a narrow fissure in the rind, 



[4] 



