DIDYMIUM 119 



1829. Physarum ccesium Fr., Syst. Myc. 3 : 147. 



1832. Licea macrospora Schw., Trans. Am. Phil. Soc. II. 4 : 258. 



1836. Diderma nitens Klotzsch, in Sm., Engl. Fl. 5 (2) : 311. 



1837. Diderma neesii Corda, Icon. 2 : 23. 



1849. Leocarpus cyanescens Fr., Summ. Veg. Scand. 450. 



1850. Diderma libertianum Fres., Beitr. Myc. 28. 



1864. Didymium libertianum (Fres.) de Bary, Mycetozoen 124. 



1873. Chondrioderma difforme (Pers.) Rost. in Fuckel, Symb. Myc. Nachtr. 73. 



1876. Chondrioderma liceoides Rost., Mon. App. 17. 



1899. Diderma persoonii Macbr., N. A. Slime-Moulds 96. 



1919. Didymium tubulatum Jahn, Ber. Deutsch. Bot. Ges. 36 : 663. 



Plasmodiocarpous, the smooth, white outer peridium separable 

 from the thin, colorless or purplish inner layer; capillitium of rather 

 coarse, flat, dichotomously branching threads, broader below; spores 

 minutely warted or almost smooth, dark brown, 12-14 /x. 



The white crust-like outer wall has more than once carried this 

 species into Diderma. It is doubtful whether or not Chondrioderma 

 calcareum Rost. should be referred here. Miss Lister cites a variety, 

 comatum, with finer and more abundant capillitium, which may repre- 

 sent Rostafinski's species. The spores seem to be paler and somewhat 

 smaller. In some of our specimens the crust-like outer peridium shows 

 crystals on the broken edge only. The var. repandum G. Lister (D. tubu- 

 latum Jahn) is characterized by tubular or funnel-shaped ingrowths 

 reaching from the upper part of the peridium to the base. It may 

 prove to be distinct. 



Reported common on Long Island by Mr. Hagelstein and in Oregon 

 by Mr. H. C. Gilbert, rare elsewhere in the United States, also re- 

 ported from Bolivia; not uncommon in the old world. 



21. Didymium quitense (Pat.) Ton. 



Fl. Myx. 150. 1909. 

 PI. VIII, Fig. 174. 



1895. Chondrioderma quitense Pat., Bull. Soc. Myc. Fr. 11 : 212. 



Sporangia more or less plasmodiocarpous, scattered, depressed, 

 white; the outer peridium distinct, crust-like, remote from the thin 

 membranous inner wall; columella undefined; capillitium brown, much 

 branched, forming a network, especially outwardly; spores very dark 

 violaceous brown, rough with a tendency to obscure reticulation, 

 12-15 n or larger, up to 17 \x. 



This species is different from D. difforme chiefly in the rougher and 

 somewhat banded epispore. The collection with large spores, 15-17 n, 

 is somewhat doubtfully here referred. 



Colorado, Montana, California, Ecuador. 



