BORNEAN FERNS. 
139 
mm lata, basi abrupte cuneata et anguste paullo decurrente, deinde 
sensim ad apicem angustata, integra, glabra, dura. 
Bungo Range, alt. 900 m, Brooks 3. 
Recognizable by the narrow, acuminate, not cordate, very rigid fronds. 
Polypodium sparsipilum Copel. spec. nova. Plate XXIII. B. 
Eupolypodium rhizomate paleis brunneis nitidis late lanceolatis 1.5 
mm longis dense obtecto ; stipitibus confertis, filif ormibus 6-9 mm altis, 
pilis horizontalibus 1.5 mm longis ornatis; fronde ca. 5 cm alta, 3-4 mm 
lata, subintegra, herbacea, diaphana, pilis sparsissimis vestita; venis 
plerisque furcatis; soris orbicularibus, subsuperficialibus, subcostalibus. 
Bengkarum, alt. 900 m, Brooks l-'i- . 
This little fern seems to be nearest to P. trichopodum F. Mueller, of New 
Guinea. The veins terminate in hydathodes. 
Polypodium setaceum Copel. spec. nova. Plate XXIV. 
Eupolypodiun rhizomate repente usque ad 2.5 mm crasso, paleis fer- 
rugineis linearibus 2—3 mm longis vestito; frondibus ad ramos breves 
articulatis, confertis, setaceis, 55 cm et .ultra longis, 1.5 min latis, in 
stipitem brevem attenuatis, integris, glabris, opacis, costa infra promi- 
nente, supra sulcata, lamina utroque .latere costae supra convexa, infra 
concava, venis occultis; soris fere costalibus elongatis. 
Tringos, Sarawak river. Brooks 6. 
This suggests P. bisulcatum Hooker, but has the fronds decidedly more slender 
and very different in cross section, and closely clustered. 
THE DRYNARIA GROUP. 
There is probably no group of organisms known which are more 
distinct in appearance but more evidently homogenetic than these are. 
Polypodium heracleum may stand in the place of the parent. By diag- 
nosis and by unquestionable affinity it is a Polypodium j or if Poly- 
podium be broken up it is still in whatever division contains P. musae- 
folium. But it is no less certainly related to Drynaria quercifolia. 
The status which shall be given to the individual members of this 
group, and the size of the minor groups are purely matters of judgment. 
We may keep all these ferns in one genus, even in Polypodium, and find 
justification enough in their obvious homogeneity— and this is the most 
important single criterion ; or we may recognize one distinct daughter- 
genus, and include in it P. heracleum or leave the latter with its . for- 
bears. At the other extreme, we may recognize a considerable number 
of' genera, most of them of a single species each ; and these genera will 
have distinguishing characters as obvious as anyone can .reasonably 
demand. Polypodiurfi coronans, Dry ostachyum pilosum , and the Bor- 
nean fern to be described below will each constitute a new genus if 
this plan be followed. 
