74 MOSSES WITH A HAND-LENS 



typical of the compactness and convenience of scientific terms. 

 It means the Twisted Moss that grows on walls. And it is on 

 walls and stones, especially those that contain lime, that one 

 should look for this moss. It grows abundantly on the mortar 

 of the wall at the upper side of the Richmond trolley line on 

 Staten Island at the point opposite the New Dorp Railroad station. 



It typically grows in small dense cushions, short, averaging 

 about ^2 inch high, dull or bright green ; leaves twisted and 

 curled when dry, oblong-lanceolate below to elongated-lingulate 

 above ; margin closely revolute, causing the leaves to appear 

 margined; costa excurrent into a very long smooth hyaline 

 hair which is usually one-half the length of the le&f; 

 capsule broadly cylindric, on a red-brown seta which is orange 

 when young. Distinct in fruiting forms by the narrow basal 

 membrane. The combination of papillose leaf-cells, smooth hair- 

 point and revolute margin will serve to distinguish from every- 

 thing except possibly Desmatodon plinthobius. 



T. RURAUS (L.) Ehrh. is larger than the preceding, I to 2^ 

 inches high, branched, bright green above, reddish-brown below ; 

 leaves recurved-squarrose above when moist, when dry appressed 

 and somewhat twisted, oblong to oblong-spatulate, rounded or 

 notched at apex; perichsetial leaves acute; costa excurrent into a 

 very long and very rough hair which is hyaline above and often 

 colored at base; margin reflexed almost to apex. The capsule is 

 cylindric, long, with lid half as long as capsule, basal mem- 

 brane constituting one-half the long peristome ; spores maturing 

 in spring. On ground in woods and on stones. Common on the 

 Pacific coast but infrequent eastward. Variable but distinguished 

 by the italicized characters. The hair-point is so very strongry 

 toothed that the roughness can be seen with a hand-lens. The 

 western forms of this species grade into the form known as 

 T. ruraliformis (Besch.) Dixon, a more robust plant with the 

 leaves acuminate; the lamina at the base of the hair-point scarious 

 and running up along the base of the hair. 



DESMATODON PLINTHOBIUS Sulliv. & Lesq. is a small moss 

 about J4 inch in height, or less, which is common in the Central 

 States. The leaves are smaller than those of Tortula muralis 

 and the hair point is often as long as the leaf, but otherwise so 

 much like that species that confusion is likely to result. The 

 small size of the plant and the short untwisted peristome will 

 serve to identifv it. 



