HYPNACEAE 239 



characteristic of PlagiotJtecium, the following genus, 

 Brachylliecium Starkcl (p. 248), and Rhynchoslegium 

 (p. 256), but I so pterygium occurs less frequently than 

 any of these, — some species being found only in moun- 

 tainous regions, — and the plants are smaller. 



Isopterygium turfaceum Lindb. {Plagiothecium tiir- 

 Jaceum Lindb.) appears to be the species most com- 

 monly collected in our range. It grows on moist, rich 

 soil or on decaying wood, sometimes in peat-bogs. 

 The plants are usually yellowish-green and often well 

 fruited. 



Isopterygium elegans (Hook.) Lindb. {PlagiotJte- 

 cium elegans (Hook.) Sull.) occurs on the ground or on 

 rocks in moist woods. The plants rarely fruit; the 

 branches usually point one way; and the leaves are 

 especially glossy, and quite a bright green. 



Isopterygium MuUerianum (Schimp.) Lindb. {Plag- 

 iothecium Milllerianum Schimp.) is found on moist 

 rocks and soil in mountainous regions, rarely fruited. 

 It grows in rather small tufts, and the branches are 

 often long, slender, and frequently taper at the ends. 



Isopterygium micans (Sw.) Broth. {Hypnummicans 

 Sw.) is a very small species occurring from New York 

 southward. The leaves are very small and slender, but 

 the branches still have a flattened look. 



