108 BOTANICAL GAZETTE [AUGUST 
from that known in other Loranthaceae. In Viscum album, V. 
articulatum, and Arceuthobium Oxycedri the sacs are similar to the 
common type of embryo sac. In Loranthus sphaerocarpus the sac 
is long and tubular, extending up in the narrow stylar canal. In 
the two species of Dendrophthora which are the subject of this study 
and Arceuthobium Oxycedri the embryo sacs originate in a quite 
similar manner in the elongated floral axes, which also bear a strong 
resemblance in general form. The sac in the latter species grows 
up to the apex of the axis where it is met by the pollen tube. As 
already shown, there is a strong similarity between the mega- 
sporangia of Dendrophthora, Thesium, and Santalum. Also the 
sacs of Dendrophthora and Santalum are much alike in their general 
shape and behavior. In the latter the sac grows downward, curves, 
and extends upward just outside of the ““mamelon.” The simi- 
larity between the genera of the Santalaceae mentioned above and 
Dendrophthora in the position of the megasporangia and develop- 
ment of gametophytes might be taken as indicative of a phylo- 
genetic relationship. . 
the two sacs formed in each flattened ““mamelon,” the one 
coward the apex of the spike becomes functional. The preceding 
description applies to this sac. It is somewhat larger and usually 
develops a little more rapidly than its mate. As a rule, the long 
arm of the latter extends a short distance above the level of the 
apex of the “‘mamelon.” The development and arrangement of 
its nuclei are the same as in the micropylar end of the functional 
sac. Only a few examples of 4 nuclei in the egg apparatus were 
found. 
The divisions of the nuclei of the sac of Dendrophthora gracile 
are usually completed much earlier than those of the sac of D. 
opuntioides. Examples were found in which the nuclei of the 
long arm of the sac were formed by the time the sac had begun its 
downward growth (figs. 44, 45). Aside from this difference in 
ah of division the embryo sacs, these two species of Dendroph- 
ord are essentially alike. No traces of mitotic divisions of the 
embryo sac nuclei subsequent to that of the megaspore mother 
cell were observed until after the maturation of the sac. The 
chromatic material of the nucleus during this period appears to 

