45° BOTANICAL GAZETTE [JUNE 
The general structure of Lepidostrobus is well known, but it 
seemed worth while to section this American specimen and to record 
the results. We have not attempted to refer it to any described 
species, as this would involve us in unfamiliar details. The only 
purpose is to describe briefly the structure of the first American 
Coal-measure strobilus to be sectioned, so far as we can discover. 
The stalks of the crowded sporophylls stand approximately at 
right angles to the axis of the strobilus (fig. 2), and are triangular 
in cross-section, the keeled abaxial face fitting between two spo- 
rangia on the sporophylls below (fig. 4). This stalklike base of the 
sporophyll is about 20 mm. long, and broadens widely as it joins 
the lamina (fig. 5), whose plane is approximately at right angles 
to that of the stalk. The lamina is 20 mm. long, extending below 
the plane of the stalk in a broad triangular base and narrowing 
rapidly above into a long acuminate extension (fig. 8). The result 
is that each lamina overlaps several others above, the surface 
appearance of the strobilus resembling that of a roof covered with 
pointed tiles; and the broad, wavy, and notched base interlocks 
with the sporophylls below. The sporangia are thus very closely 
and heavily incased, and all the structures of the strobilus are 
fitted solidly together. A single and very simple vascular strand 
traverses the stalk of the sporophyll and continues into the jJamina, 
consisting of a small central group of protoxylem elements (fig. 20), 
completely invested by a narrow zone of vessels of larger caliber, 
and this in turn by a broad zone of delicate tissue which abuts 
against the cortex. 
In the narrow space between the distal end of the sporangium 
and the base of the lamina, the ligule appears as a small conical 
body arising from a shallow pit (fig. 16). This relationship of the 
ligule to the sporangium and the lamina of the sporophyll seems to 
be constant among the ligulate forms, the distance from the base of 
the sporophyll in this case being determined by the great radial 
extension of the sporangium. The cells of the sporophyll imme- 
diately below the pit of the ligule are much longer than the other 
cells, and radiate from the ligular pit. These radiating and elon- 
gated cells perhaps indicate that in the early stages of the spor 
phyll considerable photosynthetic work was done by the ligule. 
