EXPLANATION OF PLATE XVII 



Ophiothcca wrightii Berk. & Curt. 



Figs. 429, 430, 431, 432. Habit, X 10; capillitium and spore, X 550; capillitium and 

 spore to show variation, X 550; spore and detail of spine from the same collection 

 as Fig. 431; both, X 1200. 



Perichana dcpressa Lib. 



Figs. 433, 434. Habit, X 10; spore, X 1200. 



Pcrichama quadrata Macbr. 



Figs. 435, 436, 437, 438. Habit, X 10; capillitium and spore, X 550; capillitium, 

 X 1200; spore, X 1200. 



Perkhana corlicalis (Batsch) Rost. 



Figs. 439, 440. Habit, X 15; spore, X 1200. 



Perichana marginata Schw. 



Figs. 441, 442. Habit, X 10; spore, X 1200. 



Lachnobolus congestus (Somm.) List. 



Figs. 443, 444, 445. Habit, X 10; capillitium, X 1200; spore, X 1200. 



Arcyria magna Rex 



Figs. 446, 447, 448, 449. Habit, X 5; capillitium, X 1200; spore from an Iowa col- 

 lection, X 1200; spore from Rex's collection, X 1200. 



Arcyria air sled Hi Rost. 



Figs. 450, 451, 452. Habit, X 5; capillitium, X 1200; spore, X 1200. 



Arcyria nutans (Bull.) Grev. 



Figs. 453, 454, 455. Habit, X 5; capillitium, X 1200; spore, X 1200. 



Arcyria versicolor Phill. 



Figs. 456, 457, 458. Habit, X 10; capillitium, X 1200; spore, X 1200. 



Arcyria cinerea (Bull.) Pers. 



Figs. 459, 460. Habit, X 10; spore, X 1200. 



