KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 51. N:0 3. 23 
fig. 14, they are about as broad at the base as long, ti. e. semicircular, in others 
they are only a trifle more elongated — and they have always a broad rounded 
apex. The sori appear as faint but distinct depressions on the impressions of the 
lower side of the pinnae. There is normally one in each pinnule, placed near but 
not quite close to the rachis and almost in the median line of the pinnule. At a 
close examination, however, it is seen that the position of the sorus is a little more 
distal, just forward of the midrib. The sporangia cannot be seen, but from com- 
parison with HEER's Greenland Gleicheniae and the recent genus it seems fairly certain 
that the depressions mentioned really represent the impressions of sori. 
The species evidently belongs to the subgenus Hugleichenia of the recent Glei- 
cheniae, which differs from the other subgenus Mertensia by having only one sorus 
in each pinnule. 'The position of the sorus in the Patagonian fossil species agrees 
perfectly with that in recent Hugleicheniae. Among other fossil forms, the nearest 
analogies to our species are to be found in some of HEER'S species of Gleichenia from 
the Lower Cretaceous of Western Greenland. Of the species referred by him to the 
subgenus Hugleichenia, only Gleichenia acutipennis (HEER 1874, p. 53; pl. 10, figs. 
P3) Gadelicatula (ibidem,-p.154; pl. I; -figs.!1l.e; and f; pl. 10, figs..16, 17) and 
G. optabilis (HEER 1880 b, p. 5; pl. 1, fig. 13) have the sori placed in the same 
manner as the Patagonian species. Gleichenia acutipennis differs in having longer 
and more pointed pinnules; G. delicatula, which is otherwise fairly similar to our 
form, is so much smaller and finer that a specific determination does not seem permis- 
sible. G. optabilis, on the other hand, is larger and also has somewhat more pointed 
pinnules. It seems better under these circumstances not to identify the Patagonian 
form with any of these Greenland species, admitting at the same time that there is 
a great resemblance to the latter. 
In the collections of the Palaeobotanical Museum in Stockholm there are some 
few fragments of a Gleichenites collected by Prof. NATHORST during the Swedish Arctic 
Expedition of 1883 at Helmsdale in Scotland. These fragments have never been 
described, and cannot be referred to Gleichenites cycadina (SCHENK) SEWARD, the only 
species founded on impressions which is recorded in SEWARD'S Fossil Flora of Suther- 
land (1911). These Helmsdale specimens agree, as far as their characters can be 
made out, completely with our species, also in regard to the position of the sori. A 
definite specific identification, however, would be somewhat rash in view of the poor 
quality of the material. 
The present species was found in the locality marked b on the sketch-map, text-fig.2. 
Gleichenites cf. micromerus HR. 
PEllyefigsa 165-18: 
Cf. Gleichenia micromera HEER 1874, p. 55; pl. 10, figs. 14, 15. 
A small and incomplete but well preserved specimen from the Rio Fösiles locality 
may be compared with HEER'S Gleichenia micromera. 
