PLANTS JAVANICLE RARIORES. 569
having pilose capsules ; and it is at least certain that the section of Gymnogramma referred to should be removed from that genus, and if still distinguished as a genus or subgenus, might receive the name of Pleurogramma.
This section is also manifestly related to Meniscium, which, though readily distinguished by its technical cha- racter, may be considered as a subgenus of Polypodium, nearly approaching in vascular structure to the pinnate species of Lastrea, but differing in the sori terminating the corresponding veins at their point of junction, and by their confluence forming a semilunar line. It is deserving of remark, that in some, and especially the original species of Meniscium in that part of the frond where the power of producing capsules is the weakest, the sorus is transferred from the point of union of veins to the upright branch arising from that point, and from semilunar becomes round or sublinear.
Lastrea may even be considered as approaching in [5 affinity rather more nearly to that section of Nephrodium, which M. Gaudichaud has separated under the generic name of Polystichum, than to any subdivision of Polypodium ; an approximation which appears to be confirmed by more than one fern, entirely agreeing in habit, in undivided veins and lateral fructification with this group of Nephro- dium, but having a short linear sorus, with an Indusium of corresponding form, inserted by its longitudinal axis in the middle of the sorus. To this group the name of Mesochl.ena may be given ; and though in general appearance it is abundantly different from Didymochlaena, it can only be distinguished from that genus, according to my view of the structure of its indusium, by its simple veins and lateral sori.
The most extensive but least natural section of Poly- podium is that in which none of the veins anastomose, the sorus standing either on the apex, generally more or less dilated, of the branch, or distinctly below the apex, which is then scarcely or not at all dilated ; the vein when simple, or its upper soriferous division when branched, terminating within the margin of the frond or pinna.