256 Scientific Proceedings, Royal Dublin Society. 



separating it from T. blechnoides are slight ; and until we get more positive 

 information regarding it, it may be neglected. 



For all working purposes, therefore, Taenitis is a genus of only one 

 species — T. blechnoides Willd. 



The position given to this small genus by various systematists is 

 interesting. Presl (1836) (10) places it under Grammifideae between 

 Pte.ropsis (a genus which no longer exists, but is now merged in the Vittarieae 

 and Taenitidinae) and Drymoglossum. In the Synopsis Filicum (1874) it is 

 placed under Grammitideae between Vittaria and Drymoglossum. Prantl 

 (1892) (9) placed it under Polypodieae, sub-group Taenitidinae, along with 

 such forms as Gheiropleuria and Platytaenia. Christ (1897) (2) places it 

 under the Polypodieae between Pcdtonium and Drymoglossum. Diels(1902) (5) 

 places it in the Taenitidinae (Polypodieae) along with Drymoglossum, 

 Hymenolepis, Paltonium, Platytaenia; but widely apart from the Asplenieae- 

 Blechneae (2, p. 245), which includes Blechnum itself. In Engler's syllabus 

 (1912) (6) it is again placed under the Taenitidinae along with Drymoglossum, 

 and ranked under the Polypodieae ; while Blechnum, with which it has often 

 been related, lies apart from it in the Asplenicae. 



The following will be an attempt to study, as far as possible, the structure 

 of Taenitis with a view to placing it in its true phyletic position. 



External Morphology. 



The rhizome of Taenitis blechnoides may be variously inclined to the 

 vertical. Leaves arise on all sides at a distance of about half an inch apart 

 and roots may occur at any point on the surface. The leaves are erect, of 

 about a foot to a foot and a half in length, and they are simply pinnate 

 There is no dimorphism of the leaves, sterile and fertile ones being identical 

 in size. The sorus forms a continuous line midway between the margin and 

 the mid-rib ; but towards the distal end of the pinna it usually becomes 

 broken into short portions, and finally disappears. Similar interruptions may 

 also occur occasionally lower down on the leaf blades. There is no indusium 

 visible in the mature state. 



On the base of the petiole is frequently found a bud situated marginally 

 on the stalk. Both the stem and the base of the petioles are covered with 

 hairs and very simple scales. 



Dermal Appendages. 



The hairs (Plate XV, B, 1) consist of a single row of cells, the terminal 

 one being glandular as in Blechnum. The cells at the base are larger than 



