BORNEAN FERNS. 
141 
§ HEMISTACHYUM. 
^ 
Sons compositis^ inter costam et marginem pluribus. 
1. A. Brooksii Copel. spec. nova. Plate XXV. 
Fronde ca. 120 cm alta, ad basin sicca, 35 cm lata, hiiiiiifera, arti- 
culatione vestigiale, parte apicale 25 cm alta sohimmodo pinnata fer- 
tile; pinnis fertilibus usque ad 18 cm longis, 15 mm vel ultra latis, apud 
rhachin dilatatis, soris compositis, inter costam et marginem 3 vel 4, inter 
venas 2 aut per coalescentiam 1. 
Sarawak, Penrissen mountain, alt. up to 900 m, common but seldom fertile. 
Brooks 39 (Type) ; Benkarum mountain, on summit, Brooks 37. The latter is 
the plant mentioned in a former paper, Philip. Joum. Sci. 5 (1910) Bot. 285, 
as an apparent hybrid between P. heracleum and Dryostackyum splcndens. 
This is clearly tlie most primitive known Aglaomorpha, and the specialization 
of its fertile segments is neither very great nor very firmly fixed. The type 
has, below the strictly fertile segments, one with a fertile tip; and the Beng- 
karum specimen has only two fertile segments, which are a little below the apex. 
The whole group is' a very new one, and T have individuals of each of the other 
species of the genus, in which the distinction between fertile and sterile segments 
is more or less broken down. 
§ DRYOSTAOHTUM. 
2. A. splendens (J. Sm.) Copel. comb. nova. 
Dryostaehynm splendens J. Sm. Joum. Bot. 3 (1841) 399. 
Bot. 3 (1S4I) 399. 
This species has very large, usually squarish sori, and a dilated humus-collect- 
ing base. 
3. A. pilosa (J. Sm.) Copel. comb. nova. 
Dryostackyum pilosum J. Sm., Journ. Bot. 3 (1841) 399 mniou 
Base of leaves narrowed to a stipe, and not collecting humus. Scattered fertile 
segments are not at all rare. In the absence of the humiferous base, in the 
instability of the localization of fertile segments, and in the slemler rhizome, this 
species resembles Polypodium species less specialized and more primitive than 
P. heracleum and />. coronans; however I am of the opinion that this resemblance 
is not proof of near affinity, and that A. pilosa is a simplified descendant ot 
humus-collecting species. Another possibility is that it is a hybrid of A. splen- 
dens B.n<l Photinoptcris spcciosa. 
4. A. meyeniana Schott. 
The type of the genus. 
§ PSYOMIUM. 
