234 Pickett: EMBRYO-SAC OF ARISAEMA TRIPHYLLUM 
(6) The formation of a tetrad of potential megaspores from 
some of which the embryo-sac or sacs develop, instead of from an 
archesporial cell, is shown. 
(c) More than one embryo-sac may be developed in Arisaema 
triphyllum, as Campbell (4, p. 671) has shown for other members of 
the Araceae. 
(d) The fusion of the polar nuclei is doubtful. 
(e) The antipodal cells rarely develop fully as in typical 
angiosperms. 
The writer wishes to express his gratitude to Prof. D. M. 
Mottier of Indiana University, at whose suggestion the present 
study was undertaken, for his kindly critical and encouraging 
words. 
INDIANA UNIVERSITY, BLOOMINGTON, INDIANA. 
LITERATURE CITED 
- 
* 
Strasburger. Die Angiospermen und die Gymnospermen. 1879. 
- Mottier. On the development of the embryo-sac of Arisaema 
triphyllum. Bot. Gaz. 17: 258-260. Au 1892. 
N 
3. Campbell. Studies on the Araceae. Ann. Bot. 14: 1-25. Mr 
1900, 
4. Campbell. Studies on the Araceae. Ann. Bot. 17: 665-687. S 
1903 
Gow. The embryogeny of Arisaema triphyllum. Bot. Gaz. 45: 
38-44. Ja 1908. 
Rosendahl. Embryo-sac development and embryology of Wheto 
carpus foetidus. Minn. Bot. Stud. 4: 1-10. Je 1909. 
on 
a 
Description of plates 13 and 14 
All drawings were made with the aid of a camera lucida. 
Fic. 1. Longitudinal section of a young ovule with two megaspore mother cells 
in normal position shortly after the beginning of differentiation. M225: 
Fic. 2. Longitudinal section of young ovule with three SL fer dif- 
ferentiated. The two lower cells may be considered as lateral hypoder 
X225. 
Fic. 3. Longitudinal section of ovule slightly larger and older than those shown 
in FIG. I and 2, but without any clearly differentiated sporogenous cells. 225. 
Fic. 4. Longitudinal section of very young ae before differentiation of 
ee cells and beginning of integuments. 33 
FIG. 5. onevedinat — rat = showing lateral megaspore mother cell, 
ible t g beginning of p nal division of epidermal 
a 
cells. X225. 
re Me “3 
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