6o 
F. IV. Oliver. 
ON A VASCULAR SPORANGIUM FROM THE 
STEPH ANIAN OF GRAND ’CROIX. 
[With Plate I.] 
By F. W. Oliver. 
N the course of an investigation into certain seeds contained in 
the well-known silicified ‘magmas’ of Grand’Croix many 
fossilised fragments other than those forming the main subject of 
that inquiry have necessarily come under my observation. These 
include numerous fern-sporangia of varying affinity and preservation, 
for the most part detached, though in occasional instances showing 
continuity with the vegetative organs. In one instance a trans¬ 
verse section of a detached sporangium was obtained which revealed 
an organization of more than passing interest The facts of its 
structure, which are novel and perhaps unique, give rise to the con¬ 
jecture that we have in this sporangium a point not without mor¬ 
phological signification, and this quite apart from any confident 
attribution of the sporangium in question to its systematic position 
—which indeed for the present must remain a matter of opinion. 
The preparation which forms the subject of the present 
communication showed a transverse section of a sporangium, the 
wall of which possesses a lining of unmistakeable tracheal elements. 
This section is represented in photograph 1, PI. I., taken directly 
from the object. In outline the section is not quite circular, the 
diameter which coincides with the plane of symmetry slightly 
exceeding that at right angles to it. The dimensions are 
.65 mm. X -53 mm. The wall of the sporangium is unequally 
developed on the two sides. Whilst for about half its perimeter 
the wall consists of a single layer of relatively small rectangular 
cells, its other half is two, and, at places, three cells deep, and the 
cells of this side are larger, thicker walled and rounded. This 
broad indurated band represents the annulus here, and suggests a 
comparison with the sporangium of Botryopteris forcusis, B.R. 
which has been fully figured and described by Renault 1 . 
The interior of the sporangium appears filled with a mass of 
contracted and collapsed spores; the less deformed of these have 
an average diameter of .02 mm. Lying between the wall and the 
sporogenous mass is an interrupted ring of tracheal elements. 
’Aim. des Sci. Nat. (Bot.), ser. vi. vol. i. Flore fossile d’Autuii 
et d’Kpinac, pt. ii., p. 47 
