TRIPHYLLUM AND ARISAEMA DRACONTIUM 39 
Dracontium has the larger seed. The surface of both seeds is 
finely pitted and sometimes minute reddish spots are to be seen 
upon them. A. “iphyllum has a yellowish color and A. Dracon- 
“um a reddish-yellow blush. This color is due to substances in 
the wall of the inner coat of the seed, as the testa is translucent. 
In the general microscopic structure the seeds present only 
slight dissimilarities. The outermost row of cells in the testa of 
both species are brick-shaped and are set close together with their 
long axes at right angles to the radius of the seed. In both 
the walls of this outer row of cells are mucilaginous, swelling 
greatly when they come in contact with water. In A. Dracontium 
they are slightly larger and their outer walls are considerably 
thicker. A cuticle covers this row of cells in both species. Some 
of the cells below the outer row of the testa contain tannin, 
others are filled with mucilage in which raphide cells are im- 
bedded, still others have a red coloring matter within them. It 
is to these latter cells that the dotted appearance sometimes noted 
on the seeds is due. The tegmen consists of three rows of tabu- 
lar cells with very thick mucilaginous walls. In A. Dracontium 
these walls are orange-colored, and in A. ¢riphyllum yellowish in 
color and so serve to give each seed its distinctive appearance. 
There is a cutinized lamella on either side of the tegmen cells. 
The seeds of both plants are orthotropous and the embryo is 
imbedded in an abundant endosperm. In A. ¢triphyllum the endo- 
sperm appears entirely homogeneous to the naked eye, while in A. 
Dracontium there is a horny layer next the seed coats. Upon mi- 
croscopic examination, however, but slight differences are evident. 
The outer portion of the endosperm of A. Dracontium consists of 
3 to 5 rows of cubical aleurone cells with walls capable of great 
swelling in water, These cells contain granular proteid globules, 
a single crystalloid, and also a small amount of fat. The aleurone 
cells of A. triphyllum are of exactly the same character, but are 
generally only from two to four rows deep, and also a trifle smaller. 
Within the layers of aleurone cells, making up by far the greater 
part of the endosperm, are large starch-bearing cells which have 
thin cellulose walls. Numerous crystalloids are imbedded in the 
Starch of these cells. These crystalloids are slightly more nu- 
merous in the seeds of A. Dracontium. In both cases, however, 
