378 



COMPARATIVE MORPHOLOGY OF FUNGI 



it may be branched, either normally (as in R. dichotoma, Fig. 255, 4) or as 

 the result of injury. The cells of the receptacle, exclusive of the smaller 

 cells which are separated from them and which give rise to antheridia or 

 secondary appendages, may be less than 10, as in R. Sylvestri, (Fig. 254, 1) 

 while in R. Discopomae (Fig. 254, 7) and R. dichotoma there may be more 

 than 100. Their number is usually somewhat indeterminate. 



The primary axis is usually triseriate, consisting of two marginal 

 series, that on the perithecial side called the anterior; that on the opposite 



Fig. 254. — Rickia Sylvestri. 1. Mature individual. 2. Showing aborted perithecium 

 with secondary one proliferating from its base. Rickia macrandra. 3. Old individual 

 denuded of antheridia and appendage. 4. Young one with five large, and one small, 

 antheridia. 5. Antheridia of 4 enlarged. 6. Mature individual with dimorphic 

 antheridia. Rickia Discopomae. 7. Mature individual. (After Thaxter, 1926.) 



side, definitely related to the primary appendage, called the posterior, 

 the third, median or axial series which may consist of a single cell, as in 

 R. Sylvestri (Fig. 254, 1), or may be as highly developed as in the other 

 two (R. Discopomae, Fig. 254, 7) or may be wholly absent in the biseriate 

 types (Fig. 257, 4) (formerly distinguished as Distichomyces). The axial 

 series is normally associated with the inner margin of the perithecium, 

 sometimes extending far below the latter, as in R. admirabilis (Fig. 256, 

 4) often reaching nearly to its apex or even higher than the posterior 

 series in R. elegans. Ordinarily the cells of the axial series produce 

 neither antheridia nor appendages, although in R. pallida (Fig. 255, 1) 



