172 BOTANICAL GAZETTE [SEPTEMBER 
the description given by this author seem an extraordinary per- 
formance, and none the less that apparent discrepancies with 
other species may disappear upon reexamination. His account 
of S. Martensii differs from the foregoing in the following par- 
ticulars: The megaspore when about one fourth its final size pos- 
sesses two coats, exine and intine. Against the inner surface of 
the latter lies a thick layer of protoplasm inclosing a transpar- 
ent fluid in which floats a large ‘‘nucleus.”” Near the apex “the 
protoplasm has a different appearance,” but he was unable to 
interpret it. Obviously, he misinterpreted the so-called nucleus, 
which is the protoplasmic vesicle, and in all probability the 
peculiar appearance near the apex was due to the presence of 
the real nucleus. A dome-shaped diaphragm separates the 
gametophyte into two regions. This he thinks arises at the first 
division of the spore into twocells. The one toward the apex 
of the spore becomes subdivided into a tissue three layers thick 
in the middle, one layer at the periphery. The continuous 
division of the lower cell fills the basal portion of the spore with 
larger cells. The hollow spherical portion of the gametophyte 
below the disk he describes as becoming filled with ‘ frei- 
gebildete Primordialzellen.” He could not demonstrate the 
presence of nuclei in these cells, but regards it as probable. 
According to his statement, the growth of the prothallium occurs 
at two periods. The disk-shaped mass of cells appears before 
the spores are shed, the tissue below the diaphragm, the “ sec- 
ondary endosperm,” afterward. Archegonia do not develop 
until the spores fall. 
In 1894 Heinsen reexamined the species studied by Pfeffer. 
He fell into the same error as regards the interpretation of the 
protoplasmic vesicle and nucleus in the young megaspore. He 
was unable to determine the origin of the megaspores, other 
than that a tetrad arose endogenously in the spore mother cell. 
He denied the existence of a primary and secondary endosperm, 
and of a diaphragm, and corrected Pfeffer’s misinterpretation of 
the food balls in the gametophyte cavity “as freely formed cells.” 
Infrequently he found the archegonia formed in unshed spores- 
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