94 American Midland Naturalist Monograph No. 6 



narrowed in the middle, more or less undulate, plane-margined, often incurved 

 and sub-cucullate at apex; costa strong,- reddish, ending just below apex, dor- 

 sally scabrous; basal leaf-cells hyaline, rectangular to elongate rectangular, 

 1-4:1, the marginal often forming a distinct border of a few rows of linear- 

 elongate cells, upper leaf-cells hexagonal-quadrate, about .015 mm, multi- 

 papillose, incrassate-pellucid, usually regularly seriate; perichaetial leaves 

 oblong, abruptly long lanceolate-acuminate: seta long, red; capsule long, cylin- 

 dric, dextrorsely orange-striate, furrowed when dry; peristome double, the teeth 

 filiform, papillose, articulate, red, the inner peristome of 16 or 32 filiform pale 

 segments half as long as the teeth and adherent to the latter by the broad 

 puncticulate basal membrane; lid narrow, long, rostrate, erect; calyptra very 

 long, cylindric, scabrous at the tip of the long and slender beak, extending 

 considerably below the capsule and laciniate at the border; spores mature in 

 late summer; dioicous. 



On rocks, walls, earth, etc., usually in crevices on calcareous substrata, 

 mainly confined to rough country. Europe, Asia, and from Ontario and Vir- 

 ginia to British Columbia. Not yet found fruiting in North America. 



Rare in our region. Cambria Co.: Cresson. T. P. James. (Porter's Catalogue). 

 NX'estmoreland Co.: In limestone rock on Chestnut Ridge, 2 miles east of Hillside, 

 Charles M. Boardman, May 30, 1936 (figured). 



Family 7. Grimmiaceae 



Autoicous or dioicous: cespitose, dark green to blackish: stem mostly 

 without central strand, radiculose only at the base, branches mostly of equal 

 height, leaves often hyaline-pointed, often piliferous, but rarely crispate, when 

 damp more or less spreading, rarely secund, mostly lanceolate, rarely and then 

 only upwards denticulate, towards the apex and at the margin two to several 

 cells thick, sometimes papillose; costa complete or nearly so; cells small, often 

 sinuate-walled; above mostly rounded-quadrate, towards the base inflated and 

 mostly pellucid, rectangular to elongate, rarely linear throughout the whole 

 leaf: seta rarely shorter than the capsule; capsule mostly symmetric, globose 

 to cylindric, mostly smooth, often immersed or emergent; annulus present, or 

 none at. all; teeth 16, mostly separate to the insertion, red to orange, papillose, 

 plane, undivided or cleft or cribrose, rarely divided to the base into filiform 

 parts, trabeculae mostly projecting only outwards; operculum mostly rostrate, 

 sometimes deciduous with the attached columella; calyptra mostly small, 

 mitrate or cucullate, glabrous, sometimes campanulate and plicate. 



A large family, world-wide in distribution, but most abundant in sub-arctic 

 and temperate regions, mostly on stones or rocks, rarely on soil or trees. In 

 Grout's Moss Flora the Hedwigiaceae are included as a sub-family of the 

 Grimmiaceae. 



Key to the Species 



.■\. Costa with basal guides, or homogeneous; calyptra rarely campanulate; spores small 

 to medium-sized B 



A. Costa with several median guides; spores small; calyptra campanulate; basal leaf- 



1. Ptychomitrium 



