Anatomy of the Ophioglossaceae. /. 207 
endodermis are seen in Text-fig. 9. / and 12 - 14 . and will be referred to 
later. This account will, however, suffice to make clear the longitudinal 
reconstructions, to the consideration of which we may now turn. 
The conventions upon which the diagrams (Text-figs. 3-8) have 
been constructed must be borne in mind in making deductions from them. 
The diagrams represent the stele of the stem and the leaf-traces departing 
from it. Only the xylem and the endodermis are indicated, but it will be 
understood that conjunctive parenchyma, phloem, and pericycle come in 
order between the xylem and the external endodermis ; phloem is wanting 
opposite the leaf-gaps and there is no internal phloem. The leaf-traces, 
which are really spirally arranged, are represented as if they formed two 
orthostichies and arose alternately. The level of origin of root-traces 
is indicated, but it must not be inferred that they arise vertically below the 
leaves as shown; for this reason the endodermis is not represented as 
disturbed by the root-traces. The position of the apex of the stem is indi- 
cated by a star, and the crosses in the leaf axils mark the position of vestigial 
lateral buds. The xylem of the stele and leaf-traces is represented as 
if seen in longitudinal section. So also is the external endodermis, which 
is represented by a line. The internal endodermis is supposed to be seen 
in surface view also, as if the stele were split in half ; the extent of an 
incomplete internal endodermis can thus be represented. The surface view 
of the internal endodermis is dotted, and the slight inward extension of the 
endodermis round the margin of the leaf-gap is similarly shaded. When 
the internal endodermis was complete its section is represented by a line. 
The convention by which the endodermis is represented will be readily 
understood by comparing the reconstruction in Text-fig. 8 with the trans- 
verse sections of the same stele in Text-fig. 9. The diagrams were ail 
constructed to the same scales, but the longitudinal and transverse scales 
are different, so that the stele is represented as broader in proportion to its 
length than is actually the case. Owing to its length, Text-fig. 7 has had 
to be reduced as compared with the other reconstructions. 
All the six plants showed at the base a small stele with solid xylem. 
This basal region was complete in all except plant E, and with this excep- 
tion all the plants showed the crowded first-formed roots. A number 
of roots were attached before any leaf-trace or leaf-gap was evident. From 
Bruchmann’s account of the development of the sporophyte we may perhaps 
infer the existence of as many earlier scale-leaves as there are basal roots. 
If this is so, the lowest evident leaf-trace in these plants would not mark 
the first leaf ; presumably the vascular tissue in the first developed scale- 
leaves was either absent or so small in amount that it did not affect the 
stele. In some cases it may have been displaced by the cortical growth 
and become unrecognizable ; an example of this is seen in plant F, where, 
however, a corresponding leaf-gap is present in the stele. 
Q 2 
