98 BOTANICAL GAZETTE | AUGUST 
One would be prepared to expect at least several archesporial : 
cells and some division of the macrospore mother cell. The only 
thing which reminds one at all of a primitive condition is the 
division of the primary tapetal cell by a vertical wall. Were one 
to compare Typha, in this respect, with Salix and Ranunculus, it 
would appear as a more modern form than either of them. And 
were one to take the Typhacee as primitive representatives of 
monocotyledons and the Ranunculacee and Salicacez as ancient 
representatives of dicotyledons, an inference might be drawn 
favorable to the derivation of the monocotyledons from the 
dicotyledons. But such deductions, based on single characters, 
are treacherous and cannot be taken seriously. 
A complete series of stages was not at hand to trace out in 
detail the development of the embryo sac, The macrospore con- 
tinues to enlarge until the ovule has become almost completely 
anatropous before any division takes place. The nucellus beyond 
the macrospore consists of a single layer of epidermal cells, there 
being no periclinal divisions (jigs. 5-47). In the fully devel- 
oped embryo sac just before fertilization the synergids are well 
formed, with the oosphere lying immediately behind them (/igs. 
49,51). The three antipodals are already left in a caecum-like 
pocket at the lower part of the sac, while no definite cell walls 
can ‘yet be distinguished (figs. 50,52). The behavior of the 
antipodals in Typha, therefore, seems to be the same as has been 
found for Sagittaria variabilis, Lilium Philadelphicum, and some 
other monocotyledons, where the same kind of a pocket is 
developed for the antipodals. 
The two polar nuclei come in contact somewhere near the 
middle of the embryo sac and fuse there before the pollen tube 
enters the sac (figs. 49-53). In this case, therefore, the defi- 
nitive nucleus is formed without any stimulus from the entrance 
of the pollen tube, and it may be questioned whether such stim- 
ulus is ever necessary for the complete fusion of the polar 
nuclei. 
It is not necessary, in this connection, to discuss the litera- 
ture pertaining to the Typhacee, although most of the views 
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