774 Campbell .— The Embryo-sac of Pandanus. 
Angiosperms. Of these nuclei two were at the upper end of the sac, the 
others at the antipodal end. It was impossible to tell whether this stage 
represented the condition at the time of fertilization, and an effort was 
made to obtain material which would settle this question. 
Through the kindness of Dr. W. R. Shaw, of Manila, formerly instructor 
at Stanford University, a supply of carefully preserved material was secured, 
which furnished the later stages of development. Dr. Shaw writes that 
the Philippine species is probably P. coronatus, Martelli, a name supposed 
to be synonymous with P. tectorius, Soland. 
A study of the more advanced stages of P. coronatus showed that the 
older stages found in the Javanese species were very far from mature. 
A brief account of the embryo-sac of P. coronatus was published, but the 
details were reserved for further study . 1 
A summary of the results published in the earlier papers is given here, 
and in addition the history of the embryo-sac from the latest stages secured 
in the Javanese species to the condition of the mature embryo-sac shown in 
P. coronatus. The post-fertilization stages have also been carefully followed, 
including the endosperm formation and the early history of the embryo. 
The species collected in Java included two small ones, P. Artocarpus , 
Griff., and P. affinis , Kurz, and the larger widespread species, P. odoratis- 
simus , L. f., which reaches to Hawaii. Of these P. Artocarpus furnished 
the greater part of the material that was studied. 
All of the Pandanaceae are dioecious. The pistillate flowers in 
Pandanus are in dense heads, which in the smaller species are borne 
several together at the end of a short branch, each head subtended by 
a conspicuous bract. In the larger species the inflorescence is usually 
solitary and enveloped in a large number of bracts. The head of fruit may 
occasionally be nearly or quite a foot in diameter. 
The Pandanaceae have been placed close to the Sparganiaceae, the 
flowers as well as the spiky heads of fruit, especially in the smaller species, 
closely resembling those of Sparganiutn. In the smaller ones like P. Arto¬ 
carpus and P. affinis, the individual flower consists of a single carpel, which 
closely resembles that of Sparganium simplex, except for the absence of the 
conspicuous scale-like bracts that are found in the latter. In the larger 
species several carpels are more or less completely coherent and may be com¬ 
pared to the compound pistils of Sparganium eurycarpum. The carpels in 
P. Artocarpus and P. affinis (PL LIX, Fig. i) are slender and much crowded 
together into nearly globular heads. The sessile stigma is elongated and 
sharply pointed, extending down the inner face of the carpel for about one- 
third of its length. In P. coronatus and the other species with large 
syncarpous fruits, the stigmas are discoid. 
Each carpel contains a solitary anatropous ovule attached to one side 
1 Bulletin of the Torrey Botanical Club, xxxvii, 1910, 293-5. 
