54 



W. W. WATTS. 



pinnules. The main nerve in each pinnule, while not robust 

 (Kuhn's "tenera" may be accepted), projects very dis- 

 tinctly and prominently from the surface of the frond, being 

 in this respect very similar to the costa of Hypolepis 

 teniiifolia. The structure of the side-nerves is of much 

 interest. These branch off from the main nerve at a very 

 acute angle, and then ramify dichotomously, the branches 

 curving towards the margin of the pinnule (see Plate IV a, d). 

 The nerve-ends are free, and are more or less thickened and 

 dentate. Kuhn's "apice vix incrassati" hardly does justice 

 to the case (see Plate IV b). 



5. The sorus now demands attention. This is the point 

 at which, in Domin's opinion (vide supra), the data are 

 contradictory. The figures drawn by Mr. Brittlebank show 

 the sorus-structure accurately. The sporangia spring from 

 the sides of the upper nerve-branches, and lie more or less 

 on the surface of the lamina. There are no sporangia on 

 the lowest parts of the nerve-branches (cf. Kuhn's "basis 

 ima nervorum sterilis"), Plate IV c shows also that Kuhn's 

 description of the annulus as " vertical and incomplete,, 

 not reaching the base of the sporangium" is quite correct. 



We are now in a position to consider the proper place of 

 this interesting plant in Fern-Classification. 



1, That it is not an Achrostichum is already quite clear. 



2. Kuhn associates it closely with the supposed genus 

 Allosorus, of which Cryptogramma crispa (R.Br.) may be 

 taken as typical. The similarity of the sorus-structure i& 

 certainly striking, and raises the question whether the name 

 Neurosoria, is sufficiently distinctive; but the nerve-struc- 

 ture is quite different in Cryptogramma crispa and Neuro- 

 soria pteroides, being, in the former, simply pinnate, not 

 dichotomously branched, and the nerve-ends not being free,, 

 but joined together submarginally, the lines of junction, a& 

 well as the upper nerve-branches bearing sporangia. All 



