ENALUS ACOROIDEiS. 
269 
central cylinder, which occupies a rather small part of the 
whole volume of the root, is surrounded by a slightly 
developed endodermis with thin walls. The xylem has only 
very few feebly-developed vessels, whereas the phloem is 
relatively better developed. Tannin cells occur in the root, 
though rather few, and not one inside the endodermis. 
The Stem. — The cortex is strongly developed, its external 
cell-layers are cutinized and withput cell-contents ; the 
internal layers on the contrary quite filled up with large starch 
grains, which may reach a diameter of 40-50 /b, and which 
show an evident stratification just like potato-starch. The 
starch reaches its maximum in the cells close outside the 
> endodermis, which itself is entirely free from starch. The 
I endodermis differs very little from the other tissue, its walls 
are not thickened but the cells are extended in the tangential 
direction. The vascular system is also little developed. 
The vessels are very few and just as in the root are not 
lignified. Also in the parenchyma inside the endodermis 
there is some starch, whereas the tannin cells in the stem are 
very numerous, especially inside the endodermis where they 
often lie very close together, while those in the cortex are 
more scattered. They all have a coarse-grained content. 
The Leaves. — Sauvageau (28) has given us a detailed 
description of the structure of the leaves of Enalus, to 
which nothing needs to be added. In regard to the lignifica- 
tion of the mechanical elements it may be observed that so 
far as I have found in my material these elements in the 
leaves, whether young or old, never showed any reaction of 
lignification. Treatment with aniline chloride and with 
phloroglucin and hydrochloric acid showed negative results, 
while on the contrary iodine-zinc chloride (Schulz’e 
solution) gave an evident cellulose reaction. An examina¬ 
tion of the old fibres also, which after the decay of the leaves 
still remain around the stem, indicates that their lignification 
is extremely slight, almost none. They dissolve almost 
I 8(10)04 ( 18 ) 
