Oe oa \ ee ee eee 
A PROTOCORM OF OPHIOGLOSSUM 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 167 
LoREN C. PETRY 
(WITH THIRTEEN FIGURES) 
Historical 
The earliest description of the growing region of Ophioglossum 
vulgatum is by Braun (4) in 1839. He recognized the spiral 
arrangement of the Jeaves and described the sheathing of the grow- 
ing point. HorMerster (9) in 1857 described the apical cell of 
the same species as triangular in transverse section; its exact 
form was not stated. The vascular cylinder was described as a 
loose network with a large gap corresponding to each leaf. How- 
ever, he stated that the bundle connecting with the leaf is sent off 
from the upper angle of the gap. Russow (13) gave the histologi- 
cal details of the structures of O. vulgatum, and pointed out the 
positions of protoxylem and protophloem. 
The first extensive description of the anatomy of this species 
is by Hotte (10). He refuted HormersTer’s statement that the 
leaf trace attaches to the upper angle of the gap. He further stated 
that there is a root corresponding to each leaf and that the bundle 
of the leaf trace is continuous with that of the root inserted immedi- 
ately below it. The apical cell is described and figured. 
Van TiecHEM (14) in 1890 discussed the transition of the 
vascular cylinder of O. vulgatum from a solid stele to the medullated 
condition, and described an endodermis surrounding each bundle of 
the mature stem. Rostowzew (12) described the development of 
young plants of this species from buds upon roots. His figures 
indicate that the apical cell is sometimes a truncated pyramid. 
Bower (1) in 1896 described the vascular anatomy of 0. 
Bergianum as resembling closely that of O. oulgatum. He discussed 
the anatomy of the latter species and decided that the relation 
between root and leaf is variable. BRUCHMANN (5) described the 
development of the embryo of this species. The vascular develop- 
155] [Botanical Gazette, vol. 55 
