490 Boodle.—Anatomy of the Hymenophyllaceae . 
another in details, and this supports the classification of 
H. demissum , H. scabrum , and //. dilatatum close together in 
the same section of the genus in Hooker and Baker’s Synopsis. 
H. flabdlatum is there placed next to H. scabrum , which fits 
in with the structure of the former being apparently derived 
from the two-banded type. In Trichomanes , T. scandens , 
7 ". rigidum , 7 ". apiifolium , 7 ". Prieurii , and 7 ". ericoides are 
classed together (with other species not examined) in the last 
section of the genus. This agrees well with their structure. 
7 ". spicatum with 7 ". heterophyllum are classed in a different 
section from T. scandens, &c., and T. Bancroftii with T. alatum 
are placed in a third section. These four species might struc¬ 
turally form part of the same series as the above ( T . scandens , 
&c.). Hence the upright habit may have been assumed in 
three different series. 
Prantl 1 expresses his opinion of the development of the 
Hymenophyllaceae in the form of a phylogenetic tree, and 
represents Hymenophyllum and Cardiomanes (i. e. Trichomanes 
reniforme) as springing independently from the base of the 
series, the other subdivisions of Trichomanes being lateral 
branches of other series. Prantl was unable to examine the 
anatomy of T. reniforme^ and in Hymenophyllum appears to 
have examined only the simple types 2 . This partly accounts 
for his regarding the simpler structures (sub-collateral, &c.) as 
the more primitive. 
Bower’s interesting results in spore-counting 3 show that 
Trichomanes reniforme agrees with Hymenophyllum in forming 
a large number of spores per sporangium, while other species 
of Trichomanes have a low number. It is very interesting, 
therefore, that Trichomanes reniforme resembles some of the 
Hymenophyllums rather closely in structure, but differs in 
this from other species of Trichomanes . Bower regards the 
low number of spores in Trichomanes as being attained by 
1 Prantl, 1 . c., p. 58. 
2 With the exception of H.flabellatum , in which he remarks that the protoxylem 
strangely lies in the middle of the strand. 
3 Bower, The Leptosporangiate Ferns, Phil. Trans., 1899^. 64. 
