EEfALUS ACOROIDES. 
271 
and during the discharge of the male flowers, they are 
directed straight upwards. The position of the axis is 
always vertical. During the anthesis the spathe opens a 
little by gaping asunder at the top. At the same time the 
edges of the spathe-leaves are slightly rolled back, whereby 
an open passage is afforded to the loosening male flowers. 
Along the principal veins—especially on the midrib which 
forms the keel—the spathe-leaves are richly trimmed with 
long rough hairs, which are developed in especially great 
numbers at the top of the leaves. 
The male flowers are formed just as in Vallisneria, a great 
number on a common axis (PI. XXIV., A, fig. 2), on which 
every flower is fixed by a thin pedicel often 5-6 times longer 
than the flower (PL XXIV., A, fig. 3). 
In the pedipel occur a lot of large tannin cells. That these 
really contain tannin and not Raciborski’s “ myriophyllin,” 
which has been discovered by him in so many waterplants, 
is evident from the fact that ferric chloride causes typical 
tannin staining (dark black-green), and by the fact that no 
reaction occurs with Fehling’s fluid. Tannin cells were also 
observed by H. Schenck (29) in Vallisneria, even in the 
vascular bundles. Similar tannin cells occur in all vegetative 
parts of the plant, especially in the rhizome. In the male 
pedicel they lie equally distributed, except just below the 
perianth, where they are lacking on the spot where the crack 
takes place when the male flowers are detached. Here the 
tissue of the pedicel consists only of short rounded cells, 
which are poor in contents. The tannin cells appear again 
in the perianth. 
At the rupture of the pedicel the male flower suddenly 
floats up to the surface, where at the same time the leaves of 
»the perianth turn up explosively, probably owing to the 
great difference in the external pressure. At the opening 
of the flower the anthers are raised aloft in the same manner 
as in Vallisneria (PI. XXIV., A, fig. 4, 5). So far the agree¬ 
ment with this plant is complete. But in Enalus the perianth 
