480 



INTRODUCTION TO CRYPTOGAMIC BOTANY. 



5, PoTTiACEi, Br. & Sc, Mont 



Sporangia pedunculate, straight, oval ; peristome none, or 

 16-fid ; calyptra mitriform ; leaves green, composed of wide 

 large cells. Annual or biennial. 



529. These mosses are at once distinguished from Phascum 

 by their constantly pedunculate and dehiscent sporangia. 

 They are common either on newly moved soil, like Phascei, 

 or on the mudcaps of walls, or situations corresponding with 

 them in character. The fruit is either altogether destitute of 

 a peristome, as Pottia, or, as in Anacalypta, there are sixteen 

 teeth united at the base by a membrane. It is, however, not 



Fig. 106. 



a. Portion of edge of leaf of Oymnostomum curvirostrum, magnified. 

 Moug., No. 905. 



b. Ditto of Pottia truncata, var. major. Moug., No. 809. 



c. Ditto of Orthotrichum Bruchii, from the base and towards the 

 tip, with a single cell of the latter. Moug., No. 826. 



d. Splachnum luteum, young and old sporangium with a pair of 

 teeth. From Hookerian Herbarium. 



e. Buxhaumia aphylla. After Schimper. 



