434 HEPATIC^. 



species by the presence of a strand of strong, ligneous, narrow, 

 elongated cells running along the centre of the costa; when 

 fertile by the short, laciniate bracts, surrounding the erect linear- 

 cylindrical perianth, which encloses a relatively large calyptra. 



Description of Plate CXCI.— Fig. 1 and 2. Plants natural 

 size. 3. Portion of fertile plant x (Hooker). 4. Cross-section 

 of frond x 24 (Herb. Austin). 5, 6. Ditto x 16 (ditto). 7. 

 Portion of frond x 290 (ditto). 8. Female flower (bracts, 

 perianth, and calyptra) x . 9. Section of female flower, showing 

 bract, perianth, pistillidia, and germen x. 10. Bract x. 11. 

 Capsule and portion of pedicel x . 12. Portion of male stem, 

 showing perigonial bracts and ligneous strand x. 13. Perigonial 

 bract and antheridium x. 14. Antheridium x (Hooker). 



2. Pallavicinia hibernica (Hook.), Gr. 8f Benn. 



Jiongermania hibernica, Hook. Brit. Jung. t. 78, & suppL t. 4 (1816). 



Pcdlavicinia hibernica, Gr. & Benn. Nat. Arr. Brit. PI. p. 684 (1821). 



Dilaena hibernica, Dum. Comm. bot. p. 114 (1822). 



Biplolaena hibernica, Dum. Syll. Jung. p. 83, t. 2, £. 21 (1831). 



Diplolaena Lyellii, var. hibernica, Nees Nat. Eur. Leberm. Ill, p. 343 (1833). 



Diplomitrio7i hibernicum, Oorda in 8turm Deutschl. Fl. fasc. 22, p. 87, t. 23 



(1835). 

 Moerchia hibernica, Gottsche in G. &. R. Hep. Eur. Exsicc. n. 295 (1866). 

 Delin. Hook. Brit. Jung. tab. 78 et Suppl. tab. 4 ; Ekart Syn. Jung. Germ. 



tab. X. fig. 84, et tab. xiii. fig. 116a ; Husn. Hep. Gall. pi. xi. fig. 124. 



Dioicous, loosely C2esj)itose, medium to largish in size, odorous, 

 pale green colour. Fronds procumbent, loosely imbricate, once 

 or twice dichotomously furcate, oblong, margin entire, undulate ; 

 texture somewhat delicate, cells medium to rather large in size, 

 quadrate or oblong-quadrate, walls thick, no trigones, midrib 

 thick, broader than thick, 20 cells broad x 16 cells thick, 

 gradually diminishing in thickness into the lamina, usually with 

 no ligneous strands, lamina on each side of the midrib S to 10 

 cells wide composed of 2 or 3 layers of cells ; radiculose, rootlets 

 hyaline, rarely reddish. Female flowers several, produced anti- 

 cally from the mid-rib ; bracts two, surrounding base of the 



