274 HANDBOOK OF BRITISH HEPATIC^E. 



GENUS 45. DUMORTIERA, Nets. 



Fronds thin, almost without pores or scales. 

 Peduncles terminal, elongated, two-channelled. 

 Capitulum orbicular, 2-8 lobed, often hairy. 

 Involucre one-flowered, two-lipped at the 

 apex. Calyptra persistent. Capsule stipi- 

 tate, deeply cut in four to eight segments. 

 Andraecium shortly pedunculate. 



Dumortiera irrigua, Wtts. 



Fronds of a wavy dark-green, of close tex- 

 ture, without pores. Male receptacle stalked, 

 flattish. Female receptacles hemispherical, 

 five and six rayed, each ray slightly split. 



Hygropyla irrigua, Tayl. Linn. Trans. 

 XVII., 390; Mack. Hip. II., 54. Marchantia 

 irrigua, Hook. Br. Fl. V., p. 106. Dumortiera 

 irrigua, Nees Hep. 159; Cooke Hep. f. 189; 

 Carr. and Pears. Exs. 285, 286. 



In dripping place. (Fr. April, May.) 



Fronds i to 5 inches long, about I inch 

 broad, membranaceous-fleshy, procumbent, bilobed, 

 margin of the lobes elevated, slightly undulate, 

 rounded, bright green, tawny when old, one-nerved, 

 eporose, attached by fibrils along the nerve. Fruc- 

 tification dioicous mostly, sometimes monoicous. 

 Male receptacle plane above, granulate, circular, 

 depressed in the centre, hemispherical beneath, 



