204 



INTRODUCTION TO THE STUDY OF FUNGI 



that some of the species of Nectria have an early stage in 

 which the stroma develops only conidia without perithecia, and 

 that these conidial forms were in earlier times regarded as 

 autonomous moulds of the genus Tubercularia. 1 Later on 

 perithecia appear upon the old stroma, which contain asci and 

 sporidia (Fig. 94). 



There are a few species which resemble, when mature, in 

 external appearance certain species of Nectria or Dialonectria, 



but are accompanied 



Fig. 94. — D, Tuberculoma with Nectria; B, Nectria, 

 F, section of stroma ; 6, asci and sporidia, 

 Oard. Chron. 



by capitate conidial 

 forms which are not to 

 be distinguished from 

 species of the Hypho- 

 mycetal genus Stilbum. 

 Such species of the 

 Nectrieae are associated 

 under the genus 

 Sphaerostilbe. Other 

 species, formerly united 

 with Nectria, have the 

 perithecia seated upon 

 a more or less byssoid 

 subiculum ; these are 

 now separated from that genus, and united under the name 

 of Byssonectria, analogous to the Byssosphaeria of the 

 Sphaeriaceae. In another group, the perithecia, which resemble 

 Nectria, are densely gregarious, and often partially immersed 

 in a velvety subiculum, transformed from the tissues of 

 decaying Fungi. This genus is Hypomyces, each species of 

 which has also a conidial form, which precedes the 

 ascigerous, and corresponds to some genus of the Mucedineae. 

 Some of the species of Nectria and Dialonectria also 

 have conidial forms, which would be referable to the 

 Hyphomycetal genus Fusarium. In these instances we must 

 recognise the relationship between the Hyphomyceteae and 

 the Ascomyceteae, but it would be assuming too much to infer, 

 from a few examples, that all the species of Stilbum, are conidia 

 of Sphaerostilbe, or Tubercularia of Nectria, Isaria of Cordyceps, 

 1 See Gardener's Chronicle, 28th Jan. 1871. 



