84 HEPATIC^^. 



more quadrate cells with large trigones, bracts very much more 

 dentate or denticulate. 



From P. lavif/ata (Sclirad.) by its much less polished leaves, 

 its darker brown colour (never greenish), antical lobe being never 

 acute, postical entire and proportionally broader, stipules broader 

 and entire, and by its not having the pungent taste of P. IcBvigata. 



The North American species P. platyphylloidea (Schweintz.), 

 which has been confounded with it by some authors, is its nearest 

 ally, but is of a lighter yellowish colour, with longer leaves and 

 relatively smaller lobules and stijiules, and with bracts only slightly 

 dentate. Var. torva (de Not.) Lindb. (Madotheca torva, de Not. 

 MSS.) is a much smaller form with tlie stem irregularly branched, 

 and the leaves very closely imbricate and polished. 



Description of Plate XXIX. — Fig. 1. Plant natural size. 



2. Portion of branch, antical view x 11 (Killarney, Dr. Carrington)- 



3. Ditto, postical view x 11 (ditto). 4. Leaf x 11 (ditto). 5, 6. 

 Leaves x 16 (ditto). 7. Leaf and stipule x 16 (Mangerton, Holt 

 and Stewart). 8. Leaf x 24 (France, Montague). 9. Lobule of 

 leaf X 16 (Killarney, Dr. Carrington). 10. Portion of leaf x 290 

 (ditto). 11, 12. Stipules x 16 (ditto). 13. Bract x 24 (France, 

 Montague). 14. Ditto x 11 (Mangerton, Holt and Stewart). 

 15. Bracteole x 11 (ditto). 16. Ditto x 24 (France, Montague). 

 17. Perigonial bract x 16 (Oporto, Newton). 18. Ditto, expla- 

 nate x 16. 19. Perigonial bracteole x 16 (ditto). 20. Anthe- 

 ridium x 24 (ditto). 



3. Porella platyphylla (Z.), Lindb. 



Lichenastrwm arboris vitce facie, foliis minus 7-otundis, Dill. Hist. Muse. p. 501, 



t. 72, f. 32 (1741). 

 Jungermania platyphylla, L. Sp. pi. ed. 2, 2, p. IGOO (1762) ; Hook. Brit. Jung. 



t. 40 (1816). 

 Madotheca platyphylla, Dum. Couini. p. Ill (1822). 

 Pordla 'platyphylla (//.), Lindb. Muse. Seand. p. 3 (1879). 



Dioicous, ca3spitose, large, in colour yellowish, brownisli or 

 blackish green. Stems firm, ligneous, opaque, brownish or dull 

 dark green, imbricate, procumbent or suberect, irregularly pinnate, 



