MOSSES WITH A HAND-LENS 



PAGE 



7. Capsule dehiscing by four valves, as in the 



Hepaticae, almost exclusively alpine or sub- 

 alpine Andreaeaceae. 15 



Capsule dehiscing by an operculum ; peristome 

 of 1 6 jointed teeth 8. 



8. Peristome single (very rarely lacking), with 



teeth not united in pairs, but usually per- 

 forate or bifid, richly colored and rarely re- 

 flexed when dry. Plants often hoary with 

 colorless leaf apices, nearly all growing on 



rocks Grimmiaceac. 5 1 __- 



Peristome double (with one or two exceptions), 

 teeth often united in pairs, rarely perforate, 

 usually reflexed when dry, inner peristome 

 of very narrow linear erect segments. 

 Plants very rarely hoary, mostly tree-grow- 

 ing Orthotrichaceac. 78 " 



9. Peristome of four large distinct unjointed teeth 



Georgiaceae. 17 



Peristome havi-ng an inner plaited whitish cone ; 

 outer peristome of shorter teeth often pres- 

 ent. Odd plants best recognized by a refer- 

 ence to the illustrations Buxbaumiaccae. 28 



Peristome lacking, or of more than four teeth. . . .10. 



10. Peristome of 32 to 64 short teeth, joined at the 



tips to a membrane which nearly closes the 

 mouth of the capsule ; calyptra densely hairy 

 with long whitish hairs (except Cat harmed) ; 

 leaves with numerous vertical lamellae on 

 the upper surface of the costa. Plants large 

 and very dark colored, growing on soil.... 



Polytrichaceae. 18 



Peristome when present consisting of 16 to 32 

 plainly articulate teeth, frequently lacking; 

 mouth of capsule not closed by a membrane. .II.*- 



11. Capsules cleistocarpous. . . .Bruchia in Dicranaceae. 36 

 Capsules cleistocarpous. . .Astomum in Tortulaceae. 37 

 Capsules gymnostonn-s; leaf-cells small, dense 



Pottia and Weisia in Tortulaceae. 91, 64 



