OBSERVATIONS ON THE MORPHOLOGY 
OF THE AROIDS 
JAMES ELttis Gow 
(WITH FORTY-SEVEN FIGURES) 
The material for the following observations was collected in 
the greenhouses of the New York Botanical Gardens, Bronx Park, 
New York, and was worked up by the writer during the years 
tgt1 and 1912. The usual methods were used, the sections being 
cut in paraffin, and stained usually by the iron-alum-hematoxylin 
process, or triple stained with Delafield’s hematoxylin, safranin, 
and orarige G. The species are given in the order studied: 
1. Aglaonema commutatum 
At the time this work was begun, the writer was not aware 
of the work done by CAMPBELL on this species.‘ The results 
confirm CAMPBELL’s conclusions as to the seven antipodals (fig. 1) 
and the spherical proembryo (fig. 2). In the specimen here figured, 
two of the antipodals appear in process of disintegration. 
2. Aglaonema nitidum 
The staminate flower consists of a synandrium, cleft into lobes 
by 2-5 shallow creases, each lobe containing a single loculus. The 
youngest material examined showed the tapetum largely broken 
down, the pollen grains fully formed, and the first nuclear division 
completed. The division of the generative nucleus had not taken 
place. It probably occurs in the tube, and not in the pollen grain. 
The pistillate flower consists of a single carpel which contains 
one basally attached anatropous ovule. The inner integuments 
are massive, the outer being thinner and never closing over the 
inner. In the mature embryo sac there are 10 cells, 5 of which 
occupy the position of antipodals, the other 5 performing the usual 
functions. The divisions of the endosperm nucleus give rise to a 
quantity of heavy-walled endosperm (fig. 3). The antipodals, or 
* CAMPBELL, D. H., Studies on the Araceae. Ann. Botany 14:1~25. pls. 1-3. 
1900 
127] [Botanical Gazette, vol. 56 
