450 
each space between the primary veins situated half way between 
the rachis and edge oblique, one to three lines long, one line wide. 
The affinity of this species is with G. membranacea HK., a 
native of the Malay and Philippine Islands. It differs from that 
species in having a short and stramineous stipe instead of one 
that is black and 2-6 in. long; also in the character of the 
veins, the primary veins not reaching the edge and the interme- 
diate ones being much less distinct. Such a wide geographical 
separation as lies between the Philippines and South America 
need not of necessity be a bar to identity of species, since we 
have such examples as Asplenium filix-foemina and Dryopteris 
mollis that extend almost the world around. But these instances 
are quite rare; and in the genus Gymmnogramme lam not aware of 
a single species that is common to both the eastern and western 
hemispheres. 
This fern enjoys the distinction of being thé nil species, in the 
section of Se//iguea to which it belongs, that is found in the western 
hemisphere. Out of 21 known species of Se//iguea, including this, 
only 4 are natives of the new world, and of these only one occurs 
in any abundance. The fact that Gymnogramme heterophlebia has 
never been detected before is good evidence that it is a rare plant; 
for although new species of ferns are still discovered occasionally, 
South America has been pretty thoroughly ransacked and any 
fern that has hitherto escaped observation may be safely ranked 
among the rarities of that family. 
This species happily illustrates the duplication of venation in 
different genera. If the sori were round instead of long the spe- 
cies would be a good example of the sub-genus Phymatodes in Poly- 
podium, and would stand not far from Phymatodes persicariacfolium 
Schrad. 
Another exceedingly interesting species in this collection is Adt- 
antum olivaceum Baker. This belongs to the sub-genus Hewardia. 
In 1840 John Smith, of the Royal Botanical Gardens at Kew, 
then acknowledged to be one of the ablest pteridologists of his 
day, read a paper before the Linnaean Society and published a 
description in Hooker’s Journal of Botany, in which he represented 
Hewardia as an entirely new genus from Guiana, which he dedi- 
cated to his friend Robert Heward, a Jamaica botanist of that pe- 
