206 Connection of the Sporocarp in Marsilia Polycarpa. 
two elongated segments, the leaflets (Fig. 9). The bundles divide 
rapidly and in the leaflets many bundles are present. 
In Pteris semipinnata, Linn, a species with pinnules on one side 
only of the pinna, it was found that the vascular strands of the 
pinnules came off from the margin of the strand of the pinna in the 
same manner as the vascular strand of the stalk of the sporocarp in 
M. polycarpa. 
It is thus seen that the condition in M. polycarpa is exactly that 
in M. quadrifolia. In sections through the point of attachment of 
the sporocarp in both species, the vascular supply of the stalk is 
from the margin of the curved leaf-trace. The origin of the 
leaflets is also from the margin of the leaf-trace and this similarity 
in origin of the sporocarps and leaflets indicates structurally that 
the sporocarps are fertile lobes of the leaf in this as in other species 
of the genus. Further the comparison with P. semipinnata shows 
that the condition of M. polycarpa has its correlative in the leaves 
of a well-known Leptosporangiate fern. 
LITERATURE. 
1. Bower, F. O. “Morphology of Ophioglossum palmatum .” Ann. Bot., 
XCVIII. 
2. Campbell, D. H. “Mosses and Ferns,” p. 433. 
3. Chrysler, M. A. “ Fertile Spike in Ophioglossaceae.” Ann. Bot., XXLV. 
4. Goebel, If. “Organography of Plants,” p. 479, Part II. 
5. Johnson, D. S. “ Development of Leaf and Sporocarp in Mavsilia quadri¬ 
folia.” Ann. Bot., XII. 
6. Van Tieghem, Ph. Traite de Botanique, p. 1405. 
DESCRIPTION OF PLATE. 
Figs. 1-3. Transverse sections of petiole. xl75. 
Fig. 1. Transverse section taken a short distance below attachment of 
the lowest sporocarp of the leaf. 
Fig. 2. Transverse section of the vascular strand just at point of attach¬ 
ment of the vascular supply to the sporocarp. 
Fig. 3. Transverse section of the vascular strand after departure of the 
vascular supply to the sporocarp. 
Figs. 4-9. Transverse sections of petiole and leaflets. x26. 
Figs. 4-6. Series of transverse sections of petiole below leaflets showing 
the marginal branching of the vascular supply. 
Fig. 7. Transverse section showing the first two leaflets already detached 
from the rachis. 
Fig. 9. Transverse section showing constriction of the rachis itself to 
form the last two pinnae. 
Fig. 9. Transverse section of four leaflets. 
