284 
Bower. — Notes on the Morphology of 
Observations have from time to time been made on the vascular supply 
running from the petiole to the fertile spike in Ophioglossmn. Prantl 
showed in O. lusitanicum how two strands come off laterally from the 
marginal strands of the petiole, and unite to form the single strand of 
the spike. 1 A somewhat similar state, though simpler still, was traced in 
O. Bergianum , 2 where branches coming off laterally from the single petiolar 
strand fuse to form the supply of the spike. In such cases the vascular 
system of the spike is evidently a secondary derivative of that of the petiole. 
In larger species of Ophioglossmn the plan is the same, only with more 
profuse branching. But no sufficient series of drawings has been published 
giving the whole story of origin of the supply to the spike, though it has 
been suggested for various species by several authors. Accordingly, the 
changes have been depicted as seen in O. reticulatum (Fig. 22, I-X), from 
which it is clear that the five strands of the spike seen in X arise by 
successive branchings and fusions from the marginal strands of the petiole, 
while these are themselves derived by lateral branching from the original 
leaf-trace strand. This is set down explicitly to meet the statement of 
Campbell, ‘that the bundles which supply the spike are not secondarily 
given off from the main bundles of the petiole, but are themselves the 
adaxial bundles which can be traced from the base of the petiole into 
the spike.’ 3 I can only read the origin of the vascular supply of the spike 
in the species quoted as secondary, indicating that the spike is a subsidiary 
part in its relation to the whole leaf. 
Passing from the relatively stable type of Eu-Ophioglossmn with its 
single spike to those of Ophioderma and Cheiroglossa with less stability 
of the fertile tract, it is to be remembered that it has been shown that the 
leaf-trace is in them a divided one, a condition which comparison with the 
Ferns indicates to be probably later and derivative. This suggests that 
the instability of the spike seen in them is also derivative, a view which 
had already been developed before the anatomical facts came to hand. It 
has led to the seriation of the various forms already known for O.palmatum 
as showing a progression of complexity from the type of the single spike. 
The occasional branchings of the spike seen in O. pendulum are held to be 
incipient developments in a similar direction. 4 It will now be seen how the 
facts of vascular supply will relate these aberrant forms with the type of 
Eu- Ophioglossum. 
It has already been shown 5 how the strands of the fertile leaf of 
O. pendulum form at the base a semicircle open on the adaxial side (Fig. 3), 
which, however, closes higher up (Fig. 4), and then becomes flattened as the 
leaf expands (Fig. 5). This is in accord with Campbell’s drawings. 6 But 
1 loc. cit., PI. VII, Fig. 1. 2 Studies, ii, p. 68, and Land Flora, p. 463. 
3 American Naturalist, vol. xli, No. 483, p. 157. 
4 See Studies, ii, p. 28, &c., and Land Flora, p. 435, &c. 
6 Ann. of Bot., 1904, PI. XII, Figs. 3-5. 
6 loc. cit., p. 154, Fig. 13. 
