172 CHARACTERS OF TRIBES AND GENERA. 
forming an acute angle with the mid-rib, their apices pro- 
longed into a transverse, marginal vein, which becomes 
the receptacle. Sporangia seated in an extrose slit of the 
margin which represents an indusium, forming a continuous 
linear sorus. 
Type. Vittaria lineata, Sm. 
Ilust. Hook and Bauer, Gen. Fil., t. 76, B ; Moore, Ind. 
Fil., p. 21; J. Sm. Brit. and For., fig. 56. 
Oss.—This genus is abundantly represented throughout 
the tropics and sub-tropical regions of both hemispheres, 
generally growing on trees, their pendulous linear fronds 
looking like bunches of grass. A considerable number 
of species have been described by different authors. 
They differ very little in general appearance, the most 
obvious difference consisting in the sporangia being seated 
either in a slit of the margin open exteriorly, or in a groove, 
formed by the margin being involute. In my “ Genera of 
Ferns,” 1841, I separated the species possessing the latter 
character from Vittaria, and characterised them as a genus 
under the name of Teniopsis, which I afterwards found 
was synonymous with Haplopteris of Presl. Since then I 
have examined numerous herbarium specimens, and find it 
difficult in many cases to place them under the respective 
genera, and as there is no difference in general habit, and 
no practical advantage gained by the separation, I have re- 
united them, and given up Teniopsis as a genus. 
M. Fée has adopted the same course in his memoir of 
this genus, published in 1852, In that work he describes 
twenty-five species, eighteen of which are exemplified by 
figures. In his descriptions he attaches much importance 
to the fronds being membraneous or coriaceous, and to the 
mid-rib being more or less evident, but on comparing the ` 
figures with one another and with specimens, they appear - 
