282 BOTANICAL GAZETTE [APRIL 
female, or bisexual organs. Further evidence to support this 
view of the homology of the sex organs, and that the simple 
axial row of an archegonium is reduced from forms which had 
two or more, is furnished by several groups of pteridophytes. 
In three species of Equisetum (2. hiemale, E. arvense, E. 
limosum), the archegonium frequently 
consists of an egg, a shallow ventral 
canal and two neck canal cells pyriform 
in shape and lying side by side (fg. 7). 
Jeffrey (4) regards an archegonium of 
this form as typical. In his monograph 
he figures &. arvense and E. hiemale with 
two neck canal cells in this position, and 
the text calls attention to this charac- 
IG. I1.— Longitudinal teristic. 
median section of archego- ; . 
: ' = I have a few specimens showing the 
nium of Zguisetum lmo- 
sum, showing the lateral Same conditions in /soetes lacustris (jig. #). 
position of the neck canal Campbell (5) found two laterally placed 
sa: nuclei in the single neck canal cell of 
Isoetes echinospora with no intervening wall. 
Occasionally a division of the 
lowermost cell of the axial row, 
probably the “central” cell, occurs in 
Selaginella apus. This possibly may 
be interpreted as an egg and a ven- 
tral canal cell laterally placed (fg. 3). 
That they may both function as eggs 
seems evident from the case of poly- 
embryony shown in fig. 4. 
But much more striking are the 
sex organs of at least two species of Fic. 2.—Longitudinal median 
Lycopodium. It will be remembered pth bes a opener 
that the gametophytes of only eleven nee aie ack canal cells. 
species of this genus have ever been 
discovered, and that these differ so markedly among themselves 
as to be divided by Pritzel into five categories. They range from 
the simplest to the most complex gametophytes known, with the 
