DENNSTAEDTIINAE 597 
example of departure from the strict basipetal succession ; still the receptacle 
is seen to be elongated and traversed for a considerable distance upwards 
by a strand of tracheides. Such exceptions occur in about one in every 
five sori cut, and are therefore not excessively rare. These irregularities 
are of interest for comparison with those to be described for Dennstacdtia. 
In Mf. platyphylla and M. strigosa the sorus was found to be basipetal, 
the receptacle conical, and the sporangia of the same type as in the other 
species. Thus it may be concluded for Microlepia that the sorus is typically 
one showing basipetal succession of rather short-stalked, slightly oblique 
A B 
Be MY? 
Me Se 
EA 
LVL 
HH 
: Fic. 332. 
A=NMicrolepia speluncae, Baker. Sorus showing unequal lips of the indusium, and 
basipetal succession of sporangia. X100. B, C=Microlepia hirta, Kaulf. Similar 
sections to 4, but showing departures from the strict basipetal succession. X 100. 
sporangia, with reasonable regularity of orientation, inserted upon a conical 
receptacle, and protected by two unequal indusial flaps.. But that in some 
species occasional departures from the strictly basipetal succession occur, 
younger sporangia being found inserted between those which are more 
advanced. 
DENNSTAEDTIA = (Dicksonia, § Patania). 
This genus includes numerous species of more delicate habit than 
Dicksonia, and with creeping rhizomes, the solitary leaves are non-articulated, 
a character in common with Aficrolepia, and ranked as an important one 
by Smith. Hairs are ‘borne, not ramenta. The habit is like Mzcrolepza, 
but also very like Davalia, The small sori are marginal, and Prantl had 
