IOWA ACADEMY OF SCIENCES. 27 



21. Dictydium cancellatum (Batsch). 



This is rare in the hills, though so common everywhere else. 

 The specimens taken are unusually small. The stipe is short 

 and unmarked above, although exhibiting the characteristic 

 twist. This is D. cemuum (Pers.) Noes, as usually written, 

 but Batsch surely recognized and figured the species, Elenchus 

 II, 137, PL xlii, Pig. 232, and there seems no reason why the 

 specific name he used should not pass current. 



22. Perichcena corticalis (Batsch) Rost. 



Rare, but in typical condition, and on the usual habitat, bark 

 of fallen stems of Ulmus americana. 



23. Trichia fallax Pers. 



Typical in form and capillitium. Very dark colored, both 

 within and without. 



21. Trichia inconspicua Rost. 



Typical. Occurring as in Iowa on bark of fallen stems of 

 Populus tremuloides. 



25. Hemiarcyria varnej/i Rex. 



Typical. Much resembles Hemiarcyria clavata (Pers.) Rost,, 

 bnt has more slender threads, smoother and with abundant free 

 tips. 



26. Hemiarcyria clavata (Pers.) Rost. 



Rare. Probably sought too early. Doubtless as common 

 in the fall in the central hills as in other parts of the western 

 states. 



27. Arcyria incarnata Pers. 



Rare. Collected only once, in a very light, delicate form, 

 near Hot Springs. 



28. Arcyria nutans (Bull.) Grev. 



Found in small colonies on fallen willow stems, near Custer. 

 Typical. 



29. Arcyria pomiformis Rost. 



This is an exceedingly delicate form. The peridium is wholly 

 evanescent, the stipe very short, the threads regularly marked 

 by the transverse plates or ridges characteristic of the genus. 

 The spores are entirely smooth, about .008 mm. 



30. Lachnobolus incarnatus (A. & S.) Schroeter. 



Typical specimens were collected on the bark of fallen P. 

 tremuloids, near Harney 's peak. 



21. Lycogaha epidendrurn (Buxb.) Fr. 



Rare. Only a single specimen observed near Custer. 



