60 TASMANIAX BRYOPHYTA, 



family the sporopliyte terminates the main axis, or a 

 lateral branch, though in some genera this is obscure. In 

 all cases the plant is leafy, only in one genus, Zoopsis, re- 

 duction has obscured this. The two families are quite dis^ 

 tinct, though the dividing line is not easily defined. 



Metzgeriaceae. 



Generally thalloid, rarely leafy. Tissue of the frond 

 never with air-chambers or ventral scales; a midrib i3 

 generally well defined. Sporopliyte solitai'y, on the side or 

 surface of the frond, never borne on a special apparatus, 

 having an involucre and often also a pseudo-perianth. 



Plant thalloid, expanded. 



Aneura.— Fleshy, thick, at least in the middle; no 

 defined midrib. No perianth. Calyptra large, 

 fleshy, papillate. 



Metzgeria. — Membranous, wings thin, midrib very 

 narrow, well marked. Frond forked, equal 

 breadth throughout. No perianth. Calyptra 

 hairy. 



Hymenophytum. — Cylindric below, winged above. 

 Fruit from the under surface. Perianth pre- 

 sent. 



Pallavicinius. — Cylindric below, winged above. 

 Fruit on the upper surface. Perianth present. 



Symphyogyna. — Cylindric below, winged above. Fruit 



from the upper surface. Perianth absent. 

 Plant leafy. 



Treubia. — Leaves reduced to lateral lobes. Seta very 

 long. 



FossoMBRONiA. — Leaves erect closely overlapping. 

 Seta short. 



Aneura, Dum. 



Leafless, decumbent, but often with ascending 

 branches, vaguely branched, thick or membranous; no 

 distinct midrib, but thick in the middle and thinner to- 

 wards the margins; surface, or cortical layer of cells, 

 usually much smaller than the inner cells, and chloro- 

 phyll ous. Reproductive organs on short lateral branches 

 on the lower part of the frond. Perianth absent. Caly^Dtra 

 large, clavate, fleshy. Capsule on a long seta, 4-valved, 

 elators attached to the apex of the valves. Gemmae 

 formed in the cortical cells, oblong, 2-celled. 



