84 



Orthotrichum. 

 0. anomalum. 



This form is usually found growing on stones. The calyptra is very- 

 hairy and the capsule is exserted. The leaves are costate, entire, acu- 

 minate, ovate in shape. Plants form large dense cushions. They are 

 dark green. Mature in spring. 

 0. strangidatum. 



Calyptra mitrate, naked, capsule cylindric. Leaves costate, entire, 

 acute or obtuse. Margin of leaf revolute. Plants small, growing on 

 trees. Mature in spring. 

 Phascum. 



P. cuspidatum. 



These plants are very minute, with the capsule immersed. The calyptra 

 is cucullate. The capsule is globose or ovate oblong, with an apiculate 

 operculum. The leaves are entire, acuminate, with an excurrent costa. 

 They are ovate to ovate-lanceolate, often revolute in the upper part. 

 The plants are dark green, densely tufted. They grow in waste places, in 

 fields, and on clay banks. Mature in spring. 

 Philonotis. 

 P. fontana. 



Calyptra cucullate. Capsule globular. Leaves costate, serrate, 

 acuminate, revolute, ovate lanceolate. One or two plicae on either side 

 of the costa. Costa usually excurrent. Capsule large and brown, striate. 

 Seta dark red. Plants form large tufts, aquatic or semi-aquatic. They 

 are usually yellow green. Medium to large. Mature in spring. 

 Physcomitrixtoi. 

 P. turbinatum. 



Capsule urn shaped. Leaves costate, entire, acute. Costa ends below 

 the apex. Leaves are obovate, often serrate above the middle. Plants 

 are small, bright green, growing in open places. Mature in spring. 

 Physcomitrium closely resembles Potlia, but Pottia matures in the autumn, 

 and its costa is excurrent. 



POGONATUM. 



p. brevicaule. 



This species is easily recognized by the persisting protonema, which forms 

 a soft green felt like mass on fresh turned clay banks. Leaves are very 

 few and grow at the base of the plant. Calyptra is conical and hairy. 

 The capsule cylindrical. The leaves are costate, serrate. On the back 

 of the leaf, the costa forms outgrowths called lamellae. The margin of 

 the leaf is spinulose. The plants are one or two inches high and form a 

 pretty cluster with the glistening white of the operculum or calyptra. 

 Mature in autumn. 



POHLIA. 



P. nutans. 



One of the prettiest of the spring mosses. It resembles Bryum caespi- 

 ticium, but the choice of habitat is peculiar to each. The Bryum prefers 

 dry open situations, the Pohlia prefers moist soil in deep woods. The 



