FILICES 



93 



to which the stipules belong, the two posterior wings of the stipule 

 being folded together behind it ; while the chamber formed by the 

 anterior wings encloses all the younger leaves. The stipules remain 

 succulent, not merely as long as the leaves last, but even after the 

 lamina has fallen off; and adventitious buds are not unfrequent upon 

 them. The leaf-stalk is articulated immediately above the stipule ; the 

 leaf always becomes detached at this articulation by a smooth scar, 

 leaving behind the base of the leaf-stalk with its succulent stipules. 

 The primary and secondary pinnae are attached to their respective rachis 

 by similar articulations ; and at each articulation is tx. piclvimis or cushion, 

 containing collenchymatous tissue. In the mesophyll of the leaf occur, 

 in all the genera, outgrowths of the cell-walls bounding the intercellular 

 spaces and projecting into them. Where the intercellular spaces are 

 small these outgrowths have the form of humps and cones : in larger 

 spaces they elongate into long slender filaments which present a super- 

 ficial resemblance to the hyphas of Fungi, but are quite solid, and consist 

 of cuticularised cellulose. Thev are found also less abundantlv in the 

 leaf-stalk, stem, and root. Layers and bundles of sclerenchyme occur 

 in the mesophyll, but are only feebly developed and of a light colour. 

 The leaves of Kaulfussia are characterised by the presence of remarkably 

 large stomates on the under side, formed in the ordinary way, but dis- 

 tinguished by the great size of the orifice, and by the guard-cells forming 

 a narrow ring, and being surrounded by two or three layers of epidermal 

 cells, which are also arranged in a ring. There are only two semicir- 

 cular guard-cells, and the structure of these organs is ver}' different from 

 that of the stomates of Marchantia, to which they bear a superficial 

 resemblance. Lenticels occur in the leaf-stalk of many species. 

 Spherocrystals have been found in the mesophyll and leaf-stalk of 

 Marattia cicutaefolia (Kaulf.) and Angiopteris evecta (Hoffm.). 



The roots arise endoo;enouslv from immediatelv beneath the s;rowin2; 

 point of the stem. They strike obliquely downwards through the 

 succulent parenchyme of the stem, penetrating the network of the 

 ' vascular 'bundles, with which thev mav easilv be confounded, and srene- 

 rally emerging from a leaf-stalk. They are of a lighter colour, greater 

 thickness, and more delicate texture than those of true ferns, approach- 

 ing those of Ophioglossaceae. After entering the soil they branch 

 copiously and apparently monopodially. 



The sporanges are produced in large numbers on the under side of 

 ordinary leaves, each being developed, not from a single cell, but from 

 a group of cells. They are situated on the veins, and usually form two 

 rows of sori, which cover the lateral veins either for their whole length 

 or only near the margin of the leaf ; in Kaulfussia they are placed on 



