102 



THE FLORIST. 



obviously distinguishable in texture from the frond itself, there is here 

 no obvious membrane distinct from the substance of the frond covering 

 the sorus, but the margin of the frond is turned down over the spore- 

 cases, and is more or less, though very slightly, attenuated, and changed 

 in colour and appearance, the extreme edge sometimes becoming mem- 

 branous, but not usually so. Such are the covers in a portion of the 

 group now before us, which admits of being broken up into three 

 divisions, thus — 

 Sori naked or spuriously indusiate — 



Receptacles linear, reticulate-anastomosed . . $15. Hemionitidece. 

 Receptacles linear, simple or forked, sometimes short- 

 linear, i.e., oblong . . . . . . $16. Gymnogrammece. 



Receptacles oblong, parallel, contiguous, the spore- 

 cases becoming laterally confluent, so as to simu- 

 late a broad marginal sorus, which is spuriously- 

 indusiate $17- Platylomece. 



The Hemionitidece consist of seven genera, whose sori are more or 

 less and variously reticulated. The veins are consequently reticulated 



throughout this section. 

 In Polytcenium, how- 

 ever, they, and conse- 

 quently the sori, are very 

 sparingly united, the few 

 veins forming long pa- 

 rallel lines uniting here 

 and there only ; while in 

 Anetium, Antrophyum, 

 and Hemionitis, the veins 

 are uniform-reticulated ; 

 in Dictyocline they are 

 pinnate, with reticulated 

 venules between ; in 

 Syngranima they are 



semi-reticulated ; and in 

 215. Hemionitidece : Hemionitis palmata. 7-, . . ., 



Uiclyogramma they are 

 combined in the transverse-costal form, the intermediate venules 

 reticulated, and the marginal ones free. 



The Gymnogrammece differ from the foregoing in having their naked 

 lines of spore-cases, not reticulated, but either simple or forking, the 

 simple lines being sometimes short, so as to be merely oblong, though 

 more commonly they are linear. They comprise nine genera, namely : 

 Pterozonium, Gymnogramma, Grammitis, and Calymmodon, with free 

 veins; Stegnogramma and Ampekplens, a somewhat doubtful genus, 

 with the veins connivent ; Digvammaria, with transverse-ccstal com- 

 bined veins ; and Loxogramma and Selliguea, with reticulated veins. 



The Plalylomece have usually been associated with Pteridice, doubt- 

 less because their laterally confluent sori form a marginal line of spore- 

 cases, but the structure is wholly distinct. In Pteris the sori are 

 transverse to the veins, but the Plalylomece belong to the series in 

 which the sorus is parallel to the vein. The peculiar characteristic, is 

 that the forking and not very distant veins bear the sori along a portion 



