432 EEFATICjE. 



Genus 40. PALLAVICINIA, Gr. 8f Benn. 



Pallavicinia, Gr. t Benn. Nat. Arr. Brit. PI. (1821). 



Dilmia, Dum. Comm. Bot. (1822). 



Bhjttia, Endl. (1840), G. L. N. Syn. Hep. (184G). 



Fronds prostrate or suberect, green, radiculose, strongly costate^ 

 simple or with a few postical branches, rarely furcate at the apex. 

 Inflorescence dioicous, antical. Bracts $, 2-3 series, variously 

 divided, more or less connate. Perianth large, tubular, fleshy, 

 mouth ciliolate. Calyptra included, equal or shorter than the 

 perianth, irregularly torn at the apex, somewhat delicate, below 

 the middle only somewhat fleshy and surrounded by the (about 

 20) sterile pistillidia. Capsule on a long pedicel, cylindrical, 

 composed of one layer of cells, dividing to its base into 4 valves, 

 often incompletely. Elaters slender, bispiral, deciduous. Spores 

 minute. Androecia uniseriate, situated on the margin of the 

 midrib, at the base of small incised or dentate peri gonial bracts. 

 Antheridia solitary. 



1. Pallavicinia Lyellii [Hook.), Gr. §' Benn, 



Jungermania Lyellii, Hook. Brit. Jung. t. 77 (1810). 



Palhvicinia Lyellii, Gr. & Benn. Nat. Arr. Brit. PL p. 775 (1821). 



Dilcena Lyellii, Dum. Comm. Bot. p. 114 (1822). 



Blyttia Lyellii, Endl. Gen. PI. (1840). 



Steetzia Lyellii, Lelim. PI. Preiss., TI. p. 129 (1846). 



Dioicous, in spreading patches, often stratified, medium size, 

 pale to yellowish green in colour. Fronds horizontal, simple or 

 with one or two lateral branches proceeding from the postical 

 side of the frond, oblong, nearly linear or obovate-ligulate, strongly 

 costate, costa plano-convex, postically rotundate, composed of 

 several layers of cells, with a strand of narrow, elongated, darker 

 coloured ligneous cells along the centre, sometimes two strands 

 are observed, apex of frond emarginate, very rarely furcate, 

 gradually or abruptly narrowing at the base, margin undulate, 

 entire or subserrate; radiculose, rootlets few, proceeding chiefly 



