506 FILICALES 
these genera are the two first, which were placed apart in the Synopsis 
Filicum: Dennstaedtia (as § Patania) was included in Dicksonia, while 
Microlepia was included as a section of Davallia. But evidently systematists 
had reason to know how closely allied these two were, since the synonyms 
have been numerous. The fact is that Denns/aedtia is not very nearly related 
to Dicksonia; the form of sorus is different, and the details of the sporangium ; 
these characters should weigh more strongly than any similarity of habit. 
On the other hand, A@icrolepia, while it resembles Dennstaedtia in its sorus, 
differs in some essential points from Davadiia. Certain new facts have 
confirmed the soundness of Prantl’s systematic method of founding the 
sub-tribe: it will be seen that the Ferns included in it occupy a peculiarly 
interesting position, as connecting links between the basipetal type of sorus 
seen in the Dicksonteae, and that of the Davaltias. 
Micro.eria = (Davallia, § Microlepia). 
This genus includes Ferns with creeping rhizome, on which solitary 
leaves are borne, which are not articulated at the base. The surfaces bear 
hairs, not ramenta. The leaves are repeatedly pinnate, and bear sori with 
the indusium unequally lipped; the upper lip appears as a continuation of 
the leaf-surface, the lower lip as a membranous half-cup-shaped outgrowth : 
the result is that the whole sorus appears to be intra-marginal. 
The sorus has been examined in A@icrolepia speluncae (L.), Moore, hirta 
(Kaulf), Presl, s¢vigosa (Thunb.), Presl, and platyphylla (Don), J. Sm. In 
all these it shows in the main a basipetal succession. This is seen in 
M. speluncae, in Fig. 332 a, in which the two lips of the indusium appear 
with the characteristic inequality, the superior lip (s.) having the aspect of 
a continuation of the leaf-lobe, while the inferior lip (z.) is smaller, and has 
some similarity in positioh to the indusium of Cys¢opteris. The receptacle 
is conical, but the sporangia are not very numerous, and it is not greatly 
elongated ; it is traversed by a band of tracheides (¢v.). The order of 
appearance of the sporangia is in a strict basipetal succession, but this is 
not long maintained. The sporangia themselves are on short, rather thick, 
three-rowed stalks, and the head shows a slightly oblique form, the peripheral 
face being the more convex. The annulus is almost longitudinal, but still 
it shows a slight degree of obliquity, such as will be described below in 
Dennstaedtia apitfolta ; the orientation of the sporangia shows a considerable 
regularity on the Gleicheniaceous type. 
In Microlepia hirta there is general correspondence to AZ. speluncae as 
regards structure of the sorus and sporangium, though the succession of 
sporangia is longer, and the receptacle accordingly more elongated; but 
cases occur occasionally in which the strict basipetal succession is not 
maintained. One of these is represented in Fig. 332 B, in which there is 
a larger sporangium at the tetrad stage, and below a small one in which 
the spore-mother-cells have not yet expanded. Fig. 332 c shows another 
