60 American Midland Naturalist Monograph No. 6 



Key to the Species 



A. Capsule cernuous, unsymmetric B 



A. Capsule erect, symmetric G 



B. Leaf-cells (xsrose c 



B. Leaf-cells very slightly or not at all porose (D. condensatum Hedw. ) 



C. Leaves transversely undulate; costa not reaching, or vanishing in apex D 



C. Leaves not transversely undulate; costa percurrent to excurrent F 



D. LJpper leaf-cells elongated 1. D. rugosum 



D. LJpper leaf-cells iso-diametric E 



E. Capsule solitary; costa and lamina dorsally smooth (D. Bergeri Bland.) 



E. Capsules clustered; costa and lamina dorsally rough (D. Drummondii C. M.) 



F. Capsules clustered; guides of costa in two rows; leaves up to 15 mm long 



(D. majus Smith.) 



F. Capsules solitary; guides of costa in one row; leaves up to 8 or 9 mm long 



2. D. scoparium* 



c. Costa v/ith median guides H 



G. Costa without median guides, 2-4 stratose 6. D. longifolium 



H. Entire lamina uni-stratose; costa percurrent I 



H. LJpper lamina more or less bi-stratose; costa excurrent J 



I. Upper leaf-cells short rectangular and mamillate dorsally 3. D. montanum 



I. Uppwr leaf-cells less regular, not mamillate 4. D. flagellarc 



J. Costa and margin entire, apex usually broken off 5a. D. fulvum var. viride 



J. Costa and margin serrulate 5. D. fulvum 



1. DiCRANUM RUGOSUM (Hoffm.) Bridel 

 (D. polysetum Swartz, Schwaegrichen; D. undulatum Ehrhart) 



Plate LXI 



Tall, up to 20 cm. or more, loosely cespitose: stems erect or decumbent, 

 densely radiculose below; leaves undulate, lustrous yellowish-green; 6-9 mm 

 long, lanceolate, the upper half spinosely serrate, the lower half with recurved 

 margin; costa strong, rather narrow, vanishing in the apex, with two serrate 

 dorsal lamellae above; alar cells distinct, brownish, not reaching costa, median 

 and upper leaf-cells elongate-elliptic to linear- fusiform, incrassate and porose: 

 seta long, reddish, usually 2-5 in a cluster; capsule arcuate-cernuous, rather 

 small, when dry and empty striate and brown; spores mature in late summer 

 or early fall. 



On moist soil and on humus-covered rocks in m.oist and shady woods, 

 usually in hilly or mountainous regions. Europe, Asia, and, in North America, 

 in the northern United States and in Canada. 



Apparently rare in our region. HuNTiNGTON Co.: Porter. (Porter's Catalogue). 

 Somerset Co.: 12 mi. s.w. of Somerset. C. M. Hepner, Dec. 1, 1933 (figured). Wash- 

 ington Co.: In sandy soils in woods, near Washington. A. Linn and J. S. Simonton. 



* Dicranum Bonjeani DeNot., is regarded by Grout as a subsp)ecies of D. scoparium, 

 and separated as follows: 



Leaf-apex slender, strongly serrate, strongly falcate-secund (except some varieties), 

 leaves not undulate 2. D. scoparium 



Leaf-apex broad, often obtuse; leaves laxly spreading, rarely secund (except var. 

 alatum) , sometimes slightly undulate 2a. D. Bonjeani 



