MOSSES WITH A HAND-LENS 55 



grow on granitic rocks from Connecticut southwards. The leaves 

 slender. The spores mature in winter or early spring, 

 are crisped and without whitish hair points ; the calyptra is 

 mitrate, plicate and without hairs; the operculum is long beaked; 

 the capsule nearly smooth when dry, and the peristome teeth are 

 The crispate leaves remind one very strongly of Ulota and 

 indeed it is most likely to be mistaken for a member of that 

 genus so far as general appearance goes, but its habitat on gra- 

 nitic rocks and its long beaked operculum, scarcely striate cap- 

 sule and single peristome of slender teeth will easily differ- 

 entiate it. 



GRIMMIA AND RHACOMITRIUM 



are so much alike, except in microscopic characters, that it 

 will be much more convenient to treat them together. The 

 family description will answer for these genera. 



KEY TO THE SPECIES. 



1. Capsule exserted or at least shorter than the seta 3. 



Capsules immersed, longer than the seta 5. 



2. Seta strongly curved; leaf margins not reflexed G. Olneyi. 



.Seta straight ; leaf margins recurved 3. 



3. Stems usually elongated and slender, bearing numerous short 



clustered obtuse lateral branchlets; leaves lanceolate, acute; 



subalpine or growing on exposed rocks 4. 



Stems stout without short lateral branchlets; leaves Ungulate 

 broadly obtuse; growing near waterfalls and on wet rocks in 

 cool or elevated regions R. aciculare. 



4. Leaves without whitish hair tips R. fasciculare. 



Whitish hair tips present on some of the leaves R. microcarpum. 



5. Plants with conspicuous whitish leaf tips, columella not attached 



to operculum G. Pennsylvania. 



Whitish leaf tips absent or inconspicuous; operculum falling 



with columella attached G. apocarpa. 



GRIMMIA. 



G. APOCARPA (L.) Hedw., the Common Grimmia, is our most 

 common member of the family next to Hedwigia, for which it 

 might possibly be mistaken, but it is smaller, with whitish leaf 

 tips scarcely visible, often lacking on many of the leaves, with 

 leaves plainly costate and with margins strongly recurved. The 

 peristome is well developed and plainly visible with a lens. The 

 most distinctive character is the falling of the columella attached 

 to the operculum. This character is best ascertained by remov- 



XII. Ptychomitrium incurvum. (From Sulliv. " Icones.") 2. 

 Plant, highly magnified. 6. Apex of leaf. 12. Side view of annulus and 

 peristome tooth. 6 and 12 require a compound microscope. 



