ON A NEW GENUS OF RUBBER-PRODUCING PLANTS. 291 
The other fern which has been confounded by mein my Revision 
is the one there named Davallia dareeformis, Levinge MS., which 
is made up out of the two ferns previously known as Acrophorus 
Hookeri, Moore, and Polypodium dareeforme, Hook. I have 
thrown these two into one by misunderstanding Levinge's MS. 
note at Kew. Levinge noted that P. daregforme, Hook., was a 
Davallia ; and I erroneously assumed that he meant it to be the 
same plant as Acrophorus Hookeri. The two are extremely 
alike, as may be seen from the typical sheets of them here (type 
sheets exhibited at the Meeting); but the scales on the rhizome 
sufficiently distinguish them specifically. Col. Beddome indeed 
still maintains that they are generically distinct ; 7. e. that there 
is a small scale over the young sorus in Acrophorus Hookeri, and 
that there is absolutely no such scale in Polypodium dareeforme. 
I certainly think that the orthodox school of English pteridolo- 
gists pay far too exclusive attention to this small scale as a generic 
character throughout the whole of their arrangement, and that 
Mettenius and Mr. J. Smith have better indicated the true affi- 
nities of ferns by laying more stress on the articulation of the 
caudex and the venation. The amalgamated D. darecformis, 
Levinge, of my paper must be split in any case into two species, 
viz. — 
D. DAREÆFORMIS, Levinge,=Polypodium daresforme, Hook. 
2nd Cent. Ferns, t. 24.—Acrophorus Hookeri, Bedd. Ferns Brit. 
Ind. t. 95.—Gymnogrammitis, Griff. Ic. Pl. As. t. 129. fig. 1. 
D. Crarrır, Hook. $ Baker, Syn. Fil. 91, = Acrophorus 
Hookeri, Moore, Ind. Fil. ii. 2, not of Bedd. 
to the Natural Order Apocfnaces, from the Malayan Archi- 
On Dyera, a new Genus of prince from Plants belonging 
pelago. By Sir J. D. Hooker, F.R.S., Vice-Pres. L.S. 
[Read June 15, 1882.] 
Ix the course of studying the Apocynaces for the ‘ Flora of British 
India' my attention was drawn to two Malayan Rubber-producing 
plants which constitute a new genus of the Order. Of these, one, 
from Malacca, had been correctly referred by Mr. Dyer to Alsto- 
nia? costulata, Miquel (Flor. Ind. Bat. Suppl. 556), a Sumatran 
plant, described from leaves only, of which an authentically 
