E^TRODUCTION TO CRYPTOGAMIC BOTANY. 523 



1. MAEATTIACEiE, Kaulf. 



'Dmmk.G^M, Ag., Lindl. Agyeat^, Swartz. Poropte- 

 RIDES, Willd. 



Sori dorsal, oblong or annular. Sporangia ringless, coria- 

 ceous, more or less combined into a lobed mass, with or with- 

 out an indusium. 



590. The ringless sporangia of the ferns included in this 

 tribe are so different from those which occur in other species, 

 that they have been considered as constituting a distinct order. 

 They are, however, so evidently ferns by habit, by their circi- 

 nating aestivation and venation, by the origin of the sori from 

 the veins, &c., that, notwithstanding this difficulty, I cannot 

 make up my mind to separate them, especially since the ring- 

 less sporangia of Parkeria ; and the very imperfect develop- 

 ment of the ring in Osmunda and Todea seem to connect 

 them with more normal ferns, as do the several gradations of 

 structure in the different genera. The want of a ring is not, 

 however, the only peculiarity. The young frond is involved in 

 two appendages belonging to the base of the stipes, which per- 

 form the functions of a volva. This, however, is not more 

 truly a volva, than that of so fungoid an aspect which occurs 

 in some Balanophorce, but which really arises from the valvate 

 aestivation of the lower leaves. In Angiopteris evecta, for 

 example, the edges of the two foliaceous lobes wrap over each 

 other long before the bursting forth of the frond ; and from 

 what I have seen in other plants of the order, it appears very 

 doubtful whether they are ever continuous, as figured by 

 De Vriese.* If a bulb (Fig. 118, c) of Marattia alata be 

 examined, the base will be found composed of two or more 

 imbricating concave scales, within which the first frond is more 

 or less completely inclosed by two lobes arising on each side 

 at the base. These are never circinate, and cannot be regarded 

 as inferior pinnae, but rather as appendages of the rhizoma, as 

 they grow beneath the point at which the stem disarticulates. 

 In M. cristata, the edge at length becomes green, foliaceous, 



* MoHOgraphie des Marattiacfies, par \V. H. de Vriese et P. Hartiog. 

 Leide and Dusseldorf, 1853. 



