7 88 Campbell .— Embryo-sac of Pandanus, 
sixteen-nucleate embryo-sac of Peperomia is primitive (which we do not 
think are very convincing) 1 cannot be applied to Pandanus . Since there 
are three megaspores produced in Pandanus , the embryo-sac can at most 
represent two of these, and as it may contain more than sixty-four nuclei, to 
speak of a reduction is out of the question. We entirely agree with Ernst 2 
in believing that the time has come to recognize that the embryo-sacs with 
an increased number of nuclei are not abnormalities, but are rather older 
types of embryo-sacs which have survived. It is more than likely that 
the number of these types will be increased as a further investigation of 
the lower members of both the monocotyledonous and dicotyledonous 
series is made. 
Whether the indefinite type of structure shown by Peperomia , with its 
poorly organized egg apparatus, is an older type than that of Pandanus or 
Gunner a , where a typical egg apparatus is present, is not easy to answer, 
although we are inclined to believe that it is. 
There is little question that the type of Pandanus is more primitive 
than that of Sparganium , where the large development of antipodal tissue 
is secondary. The latter may very well be derived from the former, but 
the reverse is hardly conceivable. 
EXPLANATION OF PLATES LIX AND LX. 
Illustrating Prof. Campbell’s paper on the Embryo-sac of Pandanus. 
PLATE LIX. 
Fig. i. a , two young pistillate flowers of Pandanus affinis , Kurz. x 3. b, a somewhat older 
flower of P. Artocarpus , Griff, x 3. 
Fig. 2. Two pollen-spores of Pandanus sp., showing the small prothallial t^?) cell (%). x 600. 
Fig. 3. Median section of the nucellus of a young ovule of P. affinis. The sporogenous cell 
is still undivided, x 600. 
Fig. 4. The young embryo-sac of P. Artocarpus , with the sister cell, x. x 600. 
Fig. 5. The upper part of the young nucellus of P. Artocarpus , showing the embryo-sac and 
the two cells, x, derived from its sister cell : t, the tapetal or parietal cells, x 600. 
Fig. 6. The young embryo-sac of P. Artocarpus , with a single row of tapetal cells above it. 
The cell x is probably a sister cell of the embryo-sac. x 6co. 
Fig. 7. Young embryo-sac of P. Artocarpus , in which the primary nucleus has divided. 
Fig. 8. A somewhat older embryo-sac of the same species ; a large vacuole has developed 
in the embryo-sac. x 600. 
Figs. 9-11. Young embryo-sac of P. Artocarpus with four nuclei. In Figs. 9 and 10, a is the 
micropylar region ; b , the chalazal. x 600. 
Fig. 12. nearly median section of an embryo-sac of P. Artocarpus with six chalazal nuclei, 
of which three show in this section ; one of the two micropylar nuclei can be seen; b , another 
section of the same, showing the second micropylar nucleus and the two sister cells of the embryo-sac. 
1 See Bulletin of the Torrey Botanical Club, xxxvi, 1909, pp. 205-20. 
3 Ernst, A.: Zur Phylogenie des Embryosackes der Angiospermen. Ber. der deutsch. bot. 
Gesellsch., xxvi, 1908, pp. 419-38. 
