186 



BRITISH MOSSES. 



Plate XXX. 



ISOTHECIE^E. 



Paet I. 

 THAMNIEiE. (TREE MOSSES). 



Fig. 1. Chaeacteeistics op Oedee. 



Capsule erect, symmetrical, distinguished by their peculiar habit ; the rhizoma 

 creeping, from which rises an erect stem, branched above, each plant forming 

 a miniature tree. 



PTEROGONIUM. 



Capsule erect, on a long seta, regular, oblong. Peristome double, the 

 outer of sixteen short, linear-lanceolate teeth ; the inner a membrane divided into 

 sixteen short teeth adhering to the outer. 



Fig. 2. Pteeogonium pilipoeme. 

 Thread-like Wing Moss (a) . 



Colour. Yellow green. 



Stems. Slender, tufted, branches incurved. 



Leaves (b) . Elliptical, secund ; margins recurved ; serrated at the apex, one or 



two-nerved at the base. 

 Flowers and Fruit. Dioicous ; seta twisted to the left ; lid long. Fruit very 



rare in Britain. Spring. 

 Locality. Mountainous places in Scotland and Ireland, on rocks and tree trunks. 



Fig. 3. Pteeogonium geacile. 



Slender Wing Moss (a) . 



Colour. Yellow green. 



Stems. Arched, branches incurved ; growing in large patches. 



