1%] ORIENTATION OF THE PLANT EGG 311 
iterpretation. Hofmeister’s™® classic memoir is the first paper 
importance that deals with the embryogeny. In pl. 2, fig. 20 
ithe work cited he figures the first segmentation stage, and in 
ig. 27 shows an octant stage. Other less correct intermediate 
sages are figured in p/. 3, but the fig. 73, which gives a view of 
am embryo with developed cotyledon, is excellent. Nearly 
thirty years later Kienitz-Gerloff*? undertook an examination of 
this plant, and concluded a research characterized by accurate 
_ servation of the earlier stages, coupled with erroneous con- 
_ eption of the later. His series of figures in the work cited 
ary the embryo from the stage just succeeding the octant 
sage up to ligular development. Farmer*® in 1890 incidentally 
considered the embryogeny and came to the conclusion that the 
list root was adventitious. 
The segmentation of the Isoetes egg is briefly as follows : 
The egg is cleft by a wall nearly perpendicular to the axis of 
—achegone. From the hemisphere next the archegone neck, 
fet quadrant and octant walls have appeared, are developed 
tte cotyledon, the root, and, later, probably from the cotyledon 
itadrant (not the root quadrant as has been suggested), the 
Sem. “The hemisphere away from the neck develops only a 
— ™S of cells, which has been generally considered as the foot, 
atl so described. Now the development of a primary root 
a the epibasal hemisphere is so difficult an hypoticsis + 
— that Farmer’s solution of the dilemma by considering 
‘ P a an adventitious organ would necessarily be eae 
let explanation were not at hand. It can properly . 
ag however, whether the first transverse wall oe 
Wine basal wall. This has been the current miners 
um : ak embryogeny has been compared ft ee 
: . Plant which manifests, as has been indice : 
o mal bryophyte type of orientation of its egg: If, how 
: “Lor Entw; : : K.S. Gesellsch. 
Vig, ‘ BL nClungsgeschichte der Jsoetes lacustris. Abh. 
Ueber 
lca Bot. 
On Isoeres latusiy 
Wachsthum und Zelltheilung und die Entwickelung des Embryos von 
eit. 39: 761. 1881. 
is. Ann. of Bot. 5: 37- 1890. 
