388 ANNUAL REPORT SM’THSONIAN INSTITUTION, 1907. 
‘In the genus Botryopteris, type of the Botryopteridex, the stem 
(probably a rhizome) has a remarkably simple structure, the stele 
consisting of a solid strand of tracheides surrounded by phloem. 
The relatively large petioles, borne in a spiral order on the stem, 
contain a single bundle, with a characteristic w-like transverse sec- 
tion. The stem also bore numerous diarch adventitious roots, an 
indication of its rhizome nature. 
In all respects the characters of the vegetative organs were those 
of a simple type of Fern, comparable, as Renault at once recognized, 
to the recent Hymenophyllacee. The fructifications confirm the Fili- 
cinean affinities of the genus, but at the same time show it to be very 
different from any Fern now living. The sporangia, densely grouped 
in tufts on the naked rachis of a modified frond, are of large size 
(1.5-2 mm. in length) and are characterized by the broad annulus, 
forming a longitudinal band many cells in width, running the whole 
length of the sporangium on one side. No 
very close analogy for this structure is to be 
found among recent Ferns, though the areola 
of the Osmundaceous sporangium may be 
8 regarded as a shortened multiseriate annu- 
lus. In Zygopteris we have a much more 
advanced type. The stele has in some spe- 
cies a stellate contour, the prominences cor- 
responding to the insertion of the leaf traces; 
Fic. 6.—Zygopieris pinnata, the wood is of complex structure, the larger 
A, Group of sporangia in elements forming a broad external zone, 
eee pate ao while the interior is occupied by a system of 
section, enlarged. After smaller tracheides intermingled with paren- 
Heneult: chyma. In this respect there is a striking 
agreement with the structure of some Hymenophyllacez (e. g., 7'7i- 
chomanes radicans and T. reniforme), an agreement which is much 
emphasized by the fact that in several species of Zygopteris the 
branching was axillary, exactly as in the recent family. In Zygop- 
teris corrugata, however, the branching was more of the nature of a 
dichotomy. The well-known double-anchor form of the petiolar bun- 
dle is characteristic of the genus. It is rare to find any traces of 
the lamina in petrified specimens, but a large bipinnate frond with 
flabelliform leaflets has been referred on good grounds, to the genus, 
under the name of Zygopteris pinnata. The sporangia (fig. 6) are 
borne on a special fertile frond; they are characterized by the fact 
that the broad, multiseriate annulus is present on both sides of the 
pyriform sporangium. 
The genus Corynepteris includes fronds of Sphenopteroid habit 
bearing sporangia grouped in circular sori, recalling the synangia of 
A 
