DUMORTIERA. 477 



Description of Plate CCXII. — Fig. 1. Fertile frond, natural 

 size. 2. Frond, natural size. 3. Ditto, postical view. 4. Portion 

 of frond, cross-section x ?. 5. Portion of frond, antical view x ?. 

 G. Portion of frond, showing receptacle for gemma? («), and young 

 female flowers (b). 7. Female receptacle x ?. 8. Ditto, showing 

 calyptra {a), and capsule [b) x ?. 9. Portion of female recept- 

 acle X ?. 10. Spores and elaters x ?. 11. Gemma x ? (Bischoff). 



Genus 50. DUMORTIERA, Nces. 



Dumortiera, Nees in Nov. Act. N. 0. vii. (1823). 

 Hygropyla, Tayl. Linn. Trans, xvii. p. 390, t. 15 (1835). 



Fronds large, delicate, soft, with a slight costa, subdichotomous 

 or with apex emarginate, with or without pores, mostly with hair- 

 like rootlets scattered over the entire postical surface. Inflor- 

 escence terminal, dioicous or monoicous. Capitulum $ pedunculate, 

 peduncle long, bi-canaliculate, apex smooth or setose, orbicular, 

 convex or subplane, divided into 2-8 segments, segments hairj^ or 

 smooth. Involucre tubular, often setulose, apex shortly bivalved, 

 monocarpous. Perianth absent. Calyptra included, obovate. 

 delicate, rupturing at the apex. Capsule with short pedicel, 

 subglobose, deeply cut into 4-8 segments, segments afterwards 

 more or less revolute. Elaters very long, straight, attenuate at 

 each end, 1-2- or 3-spiral, deciduous. Spores globose, asperu- 

 lous. Androecia very shortly pedunculate, discoid; antheridia 

 ovate. Gemmse wanting. 



Dumortiera irrigua (//7/.y.), Nccs. 



Marchantia irrujrca, Wils. in Hook. Brit. Fl. vi. p, lOCt, n. 5 (1833). 

 Hygropyla irrigua, Tayl. Linn. Trans, xvii. 390, t. 15 (1835). 

 Dumortiera irrigua (Wils.), Nees, Nat. Eur. Leber, iv. p. 159 (1838). 

 Dumortiera hirsnta (Swartz), Steph. Sp. Hep. p. 224 (1900). 

 Dumwtiera hirsuta (Svv.), var. irrigua (Tayl.), Spruce Hep. Am. et And. p. 5GG 

 (1885) ; Schiffn. in Eng. & Prantl. Pflanzenf. 91 und 92, Lief. p. SO (1893). 



Dioicous, procumbent, large, bright pleasant green in colour, 

 when older brownish. Fronds bilobed, lobes rotundate, very 



