266 



Scientific Proceedings^ Royal Dublin Society. 



Dermal Appendages. 



Like Drymoglosswm the dermal appendage of Paltonium is a scale (Fig- 9, a) 

 the cell-walls of which are very much thickened. It differs from that of 

 Drymoglossum in its mode of attachment to the epidermis — being attached 



Fig. 9. — Paltonium lanceolatum. Scale and hairs from rhizome. 



at the base, while that of Drymoglossum is peltate, being attached in the 

 middle; and, secondly, in its bearing numerous unicellular hairs, which grow 

 out from the thinner cells in the centre of the scale. 



Anatomy. 



The stem, which is about twice as thick as that of Drymoglosswm, has an 

 advanced dictyostele, with numerous perforations. The number of meris- 

 teles present vary from 9 to 11. Hoots arise externally from the centre of 

 the meristeles. 



The leaf-trace consists of two bundles, which divide and fuse again, so 

 as to form a series of perforations at the base of the petiole. Higher up the 

 original two bundles are reverted to, and these finally fuse into one. 



Soms. 



■The sorus is linear, and lies close to the margin, which rolls over it, 

 forming a false indusium. The sporangia (Fig. 10) are like those of Drymo- 

 glossum in their vertical annulus, with thirteen to fourteen indurated' cells, 

 and the three-celled stalk. It also resembles Drymoglossum in having two- 

 sided spores. 



Venation. 



The venation of the fertile leaf of Paltonium is shown in Fig. 11. It will 

 be seen that a commissure is present below the sorus; but- it here appears 



