246 BOTANICAL GAZETTE [OCTOBER 
PSILOTACEAE 
Fig. 6 shows a magnified view of the stem of T’mesipteris tannensis, 
as viewed in transverse section. On the lower left side is a blunt 
projection from the surface of the stem, the base of a sporophyll.® 
At the top of the figure is another sharper projection, which is the 
basal portion of a foliage leaf. Subtending each of the projections 
from the surface of the stem noted above is a fibrovascular strand, 
which has recently come off from the central cylinder. Fig. 7 shows 
part of the foregoing more highly magnified, to make clear the rela- 
tions of the outgoing traces to the stele of the stem. With the greater 
magnification an additional trace can be seen emerging from the 
central cylinder on the lower right hand. In passing out none of 
these three traces subtends a gap in the central cylinder, which in this 
region is a continuous fibrovascular tube. In the upper region of 
the stem, particularly where it gives rise to sporophylls, as BERTRAND 
has pointed out,’ the central cylinder breaks up into separate strands, 
much as happens in the upper part of the axis of Phylloglossum. In 
isolated transverse sections one often sees appearances such as are 
represented in figs. 10 and rz of the present article. On the strength 
of such evidence Miss Syxes® has asserted that there are foliar gaps 
in Tmesipteris. Her own figures, however, cannot be reconciled with 
this statement. On page 71 she represents sections taken at various 
heights through a portion of the stem, and makes a diagram of the 
bundle arrangement in this region. According to her figures the gaps 
are mainly on one side of the central cylinder or stele, and no less 
than three traces are related to one of these, that is, they are derived 
from the fibrovascular strands along its lateral margins. Three other 
traces originate near smaller stelar lacunae and one comes off — 
from any gap. A greater inconstancy in the mode of origin of traces 
could scarcely be imagined. A general acquaintance with filze 
vascular anatomy should make it clear that true foliar gaps 17 the 
same region of the stem should be nearly of a size and sho z 
occur immediately above a single leaf-trace. This state of affairs 18 
® Miss SyKEs prefers to regard this as a fertile branch. cis 
7 Recherches sur les Tmesipteridées. Archiv. Bot. du Nord de la France se 
1882. 
8 Anatomy and morphology of Tmesipteris. Annals of Botany 22:63-89- ih 
