838 MR JOHN M'LEAN THOMPSON ON 



Such uncertainty of opinion regarding the systematic position of Deparia Moorei — 

 and, in fact, of the group of plants which at some time or another have borne the 

 generic name Deparia, — indicated that its position could not be defined with any 

 degree of certainty until it had been subjected to a careful investigation. This 

 investigation I undertook at the suggestion of Professor Bower, and to him I am 

 indebted for much valuable guidance and criticism. My best thanks are due also to 

 Lord Bute, in whose laboratory part of the investigation was conducted. 



Deparia Moorei, Hook., is well figured in Hooker's Exotic Ferns, on PI. xxviii. 

 It has a short, sturdy, horizontal creeping rhizome, bearing a few scales towards its 

 apex. The leaves are crowded upon the axis, and when well developed are nearly a 

 foot in length. The firm, slender rachis bears both scales and hairs, and divides into 

 three pinnae, which, taken collectively, have a cordate-deltoid circumference. The 

 broad lamina is thin but firm, and bears numerous minute hairs. The pinnae are 

 deeply cut towards their bases into broadly toothed lobes, and their venation is 

 closely reticulate. The sori are marginal or are borne on the upper surface of the 

 lamina at the ends of small veins. They are slightly stalked, and are thus distinctly 

 projecting beyond the leaf-margin or above the upper surface. At maturity the 

 indusium is cup-shaped, and has a slightly crenate margin. 



The Axis. 



The axis is a short, condensed, and slow-growing horizontal rhizome, measuring 

 some 2^ ins. in length, and, at most, \ in. in breadth. On the lateral and upper 

 margins especially of the broad blunt apex, the leaf-primordia form a close series of 

 protuberances beset with brown scales and young roots. Leaf-bases arranged in close 

 succession and numerous thin, fibrous roots occupy the remaining surface of the axis. 



Near the apex the superficial tissue is a narrow zone of small, irregular, slightly 

 sclerotic cells, raised here and there into mounds which form the broad bases of the 

 brown scales. 



In form these scales are fairly regular (fig. 19). They are lanceolate, with 

 acuminate tips, and bear on their margins curious branched or unbranched hairs 

 (figs. 13, 14), which lie along the minutely serrate margin of the scales, or jut obliquely 

 outward. Towards the attenuated and tortuous apices of the scales shorter un- 

 branched hairs predominate. The broad scale-bases are formed of minute and usually 

 colourless cells one or two layers in thickness, but the greater part of each scale 

 consists of rather thick-walled oblong cells of a light brown colour. The scales are 

 closely adpressed to the axis throughout their entire length. 



The superficial tissue in older parts of the axis is usually a broader sclerotic zone 

 from which the scales have been removed. 



Towards the apex of the axis the ground tissue consists entirely of small-celled, 

 compact parenchyma, containing abundant minute starch grains and occasional 

 crystals of calcium oxalate, but in older parts the sclerotic character has progressed 



