320 
The Ohio Naturalist. 
[Vol. V, No. 6, 
DEVELOPMENT OF THE EMBRYO SAC AND EMBRYO OF 
STAPHYLEA TRIFOLIATA.* 
Lumina C. Riddle. 
Material for the study of Staphylea trifoliata, L. was collected 
along the hanks of the Olentangy River during several Sjirings, 
killed in chrome-acetic acid and imbedded in ])araffin. The sec- 
tions jirepared varied in thickness from 8-15 microns. Analin 
safranin and gentian violet, and iron-alum haematoxylin were 
used in staining, lioth giving good results although the latter 
stain was too dense for pollen grains. 
Sta]diylea trifoliata belongs to the Family Staphyleaceae and 
to the Order Sapindales and is thus allied to the Hippocasta- 
naceae, Aceraceae, Celastraceae, and Sajiindaceae. Scarcely any 
mor])hological work seems to have been done on this Order so 
that very little comjiarison can be made between Staphylea and 
nearly related plants. Mottier, Hot. Oaz. 18:875-877, has 
rejjorted on the develo])ment of the embryo-sac of Acer rubrum 
and some ])oints of comparison will be noted later. Strasburger 
also made observations on Staphylea pinnata and Acer in 
“ Zellbildung and Zelltheilung” Jena, 1880; and “Neue Unter- 
suchungen uelier den Befruchtungsvorgang bei den Phaneroga- 
men” Jena 1884. 
As a general rule the flowers were quite normal in the num- 
ber of parts the only variation being four carpels instead of three 
in the gvnoecium. The number of ovules in each carjiel may be 
as high as eight but very rarely more than one matured in each 
cavity and often only one in the entire ca]i.sule. The ovules are 
anatropous and the liest sections were those cut across the 
ovulary. As soon as the ovules were large enough they were 
removed from the capsule before killing. The integuments 
become too woody to make microtome sections long before the 
embrvo is mature. There are two integuments on the ovule but 
no aril. 
The hypodermal archesporial cell (FI. 19, Fig. 1) ajijiears 
before there are any traces of integuments. In one case a three 
celled archesporium (Fig. 2) was found. The single arches])orial 
cell cuts off a primary parietal cell (Fig. 8) which divides to form 
from three to five tapetal cells (Figs. 4 7) forcing the mega- 
s])orocyte deep into the tissue of the nucellus. The megasporocvte 
then divides into four megaspores (Fig. 8) and the lowest becomes 
functional destroving the others as it enlarges and divides 
(Figs. 9 -10). 
* Contributions from the Botanical Laboratcirv of the Ohio State Uni- 
versity, XIX. 
