92 A Mono(jra2'>h of the Myxogastres. 



Rostafinshia, Speg., Fung. Arg., Pug. III., p. 27 ; Sacc, Syll, 

 vii., 1, p. 403 (not of Raciborski). 



I am not, acquainted with the single species constituting the 

 present genus which appears to be exceptional in the septate 

 tubes of the capillitium, &c. 



Distrih. Argentine Republic. Species I. 



Rostafinskia australis, Speg. 



Aethalia variable in form, thickly pulvinate — effused ; ecorticate, 

 surface softly velvety-tomentose, at first with a longish cottony 

 tomentum, then breaking up into powdery filaments, purple- 

 violet or bright reddish-violet; capillitium tubes of the inter- 

 mediate stratum cylindrical, 3 — 4 jx thick, branched, not septate, 

 everywhere rough with minute warts, hyaline or tinged violet, 

 tubes of inferior sterile stratum cylindrical septate, nodulosely 

 branched, 5 — 6 [x thick, smooth, brownish ; spores globose, 

 ovoid or irregular, filled with granular protoplasm, smooth, 

 bright lilac, 8 — 10 x 5 — 6 /x. 



Rostafinskia australis, Speg., Fung. Arg., Pug. III., n. 5U; 

 Sacc, Syll, vii., 1, n. 1381. 



On rotten trunks, sawdust, &c. Everywhere very common. 



Argentine Republic. 



Reticularia, Bull. 



Aethalia composed of numerous elongated, naked sporangia, 

 arranged in strata and covered with a thin, common cortex ; 

 capillitium consisting of several columella-like, slender, thin- 

 walled tubes, that give off several lateral branches Avliich 

 anastomose to form an irregular network. 



Reticularia, Bulliard, Hist. Champ., Rost., Mon., p. 240 ; 

 Cke., Myx. Brit., p. 60; Sacc, Syll, vii., p. 418. 



In the present genus numerous naked, elongated sporangia, 

 arranged in a few superposed layers or strata, are covered with 

 an external cortex. Each sporangium has its OAvn long colu- 

 mella, which gives off lateral branches that anastomose to form 

 an irregular network, the branches of contiguous sporangia also 



