260 208 
Closely allied to D. tetragona, D. megalodus and D. Poileana; it resembles D. me- 
galodus in venation and cutting but differs by its densely setose capsules and lack 
of the adpressed stellate hairs on the leaf-tissue of the under-surfaces; from D. 
Poiteana it differs by the dense stellate pubescence of stipe and rachis, the deeper 
incised pinnz and fewer anastomosing veins; as a rule only the basal pair of veins 
are united into a free excurrent vein. From D. juruensis it differs by its not-granulose 
surfaces and the not-bulbiferous rachis. 
262. Dryopteris tetragona (Sw.) Urban, Symb. Ant. 4: 20. 1903; C. Chr. Ind. 297. 
Syn. Polypodium tetragonum Sw. Prod. 132. 1788: Schkuhr, Kr. Gew. 1: tab. 18. 
? Polypodium androgynum Poir. Enc. 5: 535. 1804. 
Polypodium subtetragonum Link, Hort. Berol. 3: 105. 1833! 
Polypodium imbricatum Liebm. Mex. Bregn. 58 (Vid. Selsk. Skr. V. 1: 
210). 1849! 
(For other synonyms see Index Fil.). 
Type from Jamaica leg. Swartz (S!). As Swartz has named different forms 
D. tetragonum I consider that form typical, which is figured by Scakunr and which 
agrees perfectly with the original diagnosis. 
D. tetragona has been considered a very variable species of a wide distribution, 
and this is to a certain degree true, but I have found that about half the number 
of the hundreds of specimens named tefragona and examined by me belong to more 
or less allied species, which it is not difficult to distinguish from D. tetragona. The 
common West-Indian typical form of this shows the following specific characters: 
Rhizome shortly creeping or obliquely erect with brown scales, which are 
covered with stellate hairs. Stipes fasciculated like the rachis stramineous, quadran- 
gular, slightly and very shortly hairy by stellate hairs. Leaves somewhat dimor- 
phous, the pinnz of the fertile leaves being narrower (2 cm br.) than those of the 
sterile ones (2!/s cem br.). Lamina ovate with 6—12 pairs (generally 8) of lateral pinnze 
and à similar terminal one. Pinnze opposite or nearly so, short-stalked, oblong, 
acuminate, the lower ones narrowed towards the base, about 10 cm long by 2—2!/» 
cm broad, incised '/2 or 7/3 of the way down into close, acute, entire segments, her- 
baceous, dark-green, the under-surface generally nitid, glabrous on both surfaces, 
excepling the costze (which are flat with two low furrows) and costulze beneath, which 
are slightly hairy by spreading, simple, acute hairs, ciliate at the margins. Veins 
simple, 8—10-jugate, the basal pair united and sending a branch to the sinus, the two 
next free and reaching the margin immediately above the sinus. Sori inframedial, 
exindusiate; sporangia setose. 
The form here described is very common in the West-Indies and there fairly 
constant; nearly identical forms are found on the continent from Mexico to Ecuador; 
the specimens herefrom have, however, generally a more dull under-surface. In the 
following I enumerate the islands and countries, from which I have seen specimens 
and add some of the more important collector-numbers. 
