Jennings: Manual of Mosses 11 



3. Spores few, about 16 to 20, smooth, about 0.2 mm in diameter; leaves linear- 

 lanceolate, with percurrent costa Archtdium, p. 44 



3. Spores numerous, rarely exreedrng O.Ci mm in diameter 4 



4. Leaf-margms plane or involute 5 



4. Leaf-margins more or less revolute - 9 



5. Capsules pyriform, with a distinct neck 6 



5. Capsules globose to ovoid ' 



6. Green protoncma occasionally abundant; neck none; capsule acute 



SpoiUdera, p. 49 



6. Green protonema sparse; usually none; neck more or less well developed; 



capsule more or less rostrate Bruchia, p. 46 



7. Leaves crisped when dry, strongly papillose on both sides; operculum rudi- 

 mentary but persistent .Astomum, p. 78 



7. Leaves not crisp>ed when dry, smooth 8 



8. Calyptra cucullatc (mitrate in Pleuridium palustre); leaves linear-lanceolate 



to lanceolate-subulate Pleundium, p. 48 



8. Calyptra campanulate; leaves lanceolate-ovate to lanceolate-obovate, dentate 



or serrate Physcomitrella, p. 116 



9. Capsule apiculate; leaves papillose Phascum, p. 88 



9. Capsule not at all or faintly apiculate; leaves smooth Acaulon, p. 87 



10. Protonema long persisting; stem-leaves minute; plant looks like a grain of 



wheat sitting in a tuft of bristles Diphyscium, p. 155 



10. Protonema brownish, persistent; plant looks like a shriveled, brownish grain 



of wheat sitting obliquely on a stout seta about 1 cm high 



Buxbaumia, p. 156 



10. Protonema persistent; plants practically stemless, leaves ecostate; calyptra 



splitting down one side and usually remaining attached to the seta 



Discelitim. p. 113 



10. Protonema jsersistent; plants practically stemless (1-2 mm); costa strongly 



lamellate in apical p)ortion of the leaf Pogonatum, p. 165 



10. Protonema not persistent; calyptra not as in Discelium. If with hypophy- 

 sis see Splachnaceae, p. 110 11 



11. Peristome teeth none, or if present articulate, at least at base 12 



11. Peristome teeth not distinctly articulate 60 



12. Peristome present, sometimes imperfect 13 



12. Peristome none 52 



13. Leaves distichous, dorsally winged and clasping at the base 127 



13. Leaves not distichously' clasping and dorsally winged 14 



14. Leaves consisting of costa only, outer cells large and empty, inner small 



and chlorophyllose Leucobryum, p. 66 



14. Leaves with a lamina consisting mainly of one layerf of more or less uni- 

 form cells 15 



15. Peristome single, 16- or 32-toothed; teeth without a median longitudinal line 



on the exterior face 16 



15. Peristome double, with 16 outer teeth and an inner variously segmented or 

 almost lacking membrane: teeth mostly with a median longitudinal line on 



the exterior face 37 



16. Capsules more or less octagonal, the angles with differentiated cells, when 



dry 8-s:riate and furrowed Rhabdoweisia, p. 57 



16. Capsule not octagonal, or, if plicate, the cells uniform 17 



17. Exterior face of teeth longitudinally striate. (See also Ditrichum) 18 



17. Exterior face of teeth smooth or papillose, not longitudinally striate. (See 



also Seligeria ) 24 



18. Leaves with differentiated, often enlarged, hyaline or brownish alar cells .... 12 



18. Leaves without differentiated alar cells 19 



19. Leaf-cells strongly and coarsely papillose. (See also Oncophorus) 



Oreowfiria, p. 46 



