cee FISHER: SEED DEVELOPMENT IN PEPEROMIA 
a single tapetal cell. In fact, its position and whole antecedent 
development, being so closely similar to that so generally found in 
Angiosperms, constitute a strong bit of positive evidence for the 
view that it is a megaspore mother-cell. 
(2) As is evidenced by the occurrence of synapsis in the nucleus 
of the definitive archesporial cell, preceding its division, the two 
divisions by which these four nuclei are formed are the reduction 
divisions, as is the case in the last two divisions in the formation of 
the megaspore nuclei in all other plants in which they are formed 
—-so far as they have been investigated. In rare cases like that of 
Alchemilla speciosa (Murbeck, 53, 54; Strasburger, 74), in which ap- 
parent megaspore-formation occurs without reduction of chromo- 
somes, there is no sexual fusion in the initiation of the embryo which 
is later developed in the embryo sac. Therefore, as Strasburger 
contends, such abnormal cases can not be considered examples of 
true megaspore-formation. The presence of the reduction di- 
visions is considered by some workers as sufficient evidence for 
the acceptance of the theory of the homology of the megaspores 
of Angiosperms with those of the Gymnosperms and the higher 
Pteridophytes. It should mean as much in Peperomia as it does 
elsewhere in heterosporous plants. 
(3) The tetrahedral arrangement of these first four nuclei 
points more strongly to the homology in question than does the 
linear tetrad, or axial row, arrangement, which occurs in nearly 
all seed-plants, both Gymnosperms and Angiosperms—since a 
tetrahedral arrangement of the microspores is found in nearly all 
heterosporous plants and in the megaspores of all heterosporous 
Pteridophytes. The linear tetrad of megaspores is universal in 
the Cycadales, the Coniferales, and the Ginkgoales, in all investi- 
gated cases known to the writer; but Juel (36) found a close 
approach to the tetrahedral arrangement in the megaspores of 
Larix sibirica as a general rule, the typical axial row being seldom 
found. The tetrahedral arrangement of megaspores is not al- 
together unknown in Angiosperms, having been observed in 
Fatsia japonica by Ducamp (17). Transitions between the axial 
row and the tetrahedral arrangement have been observed in 
Aralia racemosa by Ducamp (17), in Garcinia by Treub (77), in 
Burmannia Championii by Ernst and Bernard (22), in Cynomorium 
