FEBRUARY. 



41 



The number of genera referred here is six : — Monogramma, a minute 



plant, in which there are no veins beyond the costa ; Dicliclopteris, in 



which there is only a costa and the receptacle 



distinct from but parallel with it ; Pleuro- 



gramma and Xiphopteris with free veins from 



a central costa ; and Hymenolepis and Gym- 



nopteris, in which the veins are compound 



reticulated. 



The second group (£), with linear marginal 

 receptacles, embraces a larger number of sec- 

 tions, which may be set forth thus : — 



. %i. Plkokogp.a.mmk^e : 



(6). Receptacles marginal, &C. Pleurogramnia linearis. 



Sori non-indusiate, linear, mostly immersed in a groove 

 or furrow of the frond, sometimes superficial — 



— submarginal, usually occupying a shallow dorsal 



furrow (rarely oblong) ..... |5. Tcenitidcce. 



— marginal, always occupying an extrorse-marginal 



furrow §6. Vittariece. 



Sori indusiate, superficial, linear, oblong, or rotundate — 



Indusium bursting along the outer edge . . • \7 • Lindsceece. 

 Indusium bursting along the inner edge — 

 Receptacles resupinate, i.e., the spore-cases attached 

 to the under surface of the indusium itself . 



Receptacles normal, i.e., the spore-cases attached to 

 the frond — 



— punctiform (transverse-marginal) . 



— linear (transverse marginal) . . . . 



§8. Adiantece. 



. §9. Cheilanthece. 

 . . §10. Pteridece. 



The Tcenitidece, remarkable for the furrow in which the submarginal 



spore-cases are in almost all cases 

 inserted, embrace several genera. In 

 Scoliosorus and Holcosorus the veins 

 are reduced to an obscure costa ; in 

 Tcenitis, Sckizokpton, and Loma- 

 gramma, they are uniform-reticulated ; 

 in Drymoglossum, Diblemma, and 

 Paragramma they are compound- 

 reticulated ; in Dicranoglossum the 

 veins form simple arcs, each one 

 meeting the next, along both sides of 

 the costa; and in Tceniopsis the 

 veins are free, except where combined 



§5. tam BU : T*niopsis lineata. by th(J marginal re ^ eptacle . 



The Vittariece very much resemble the genus Tceniopsis in the 

 last section, only in Tceniopsis the sori mostly occupy a furrow (they are 

 usually immersed, but not always) along the back of the grass-like 

 frond near each margin ; while in the present section, consisting only 

 of Vittaria, the furrow is along the extreme edge, its opening being 

 turned outwards, so that the spore -cases seem to lie in the split margin. 



