m 
SVEDELIUS LIFE-HISTORY OF 
entirely in concentrated sulphuric acid and leave only a 
very little remainder of the wall behind, whereas the stains 
for lignification give negative results. It is apparently only 
the middle lamella which is slightly lignified, whereas the 
thickening layers consist of unchanged cellulose. Sauvageau 
(28 , however, states concerning these “fibres scléreuses,” 
that they are totally lignified at an older stage, though 
lignification takes place very slowly, just as in Posidonia. 
Commonly water plants are distinguished by the fact that 
lignified elements are not developed in any high degree. 
Among the water plants examined by Sauvageau (27) 
Zostera marina proved most striking in that respect, as it 
lacked every trace of lignification. Other species, however, 
e.g ., Cymodocea æquorea, proved variable ; sometimes they 
totally lacked, sometimes again they had, lignified elements. 
To judge from the account of Sauvageau (28), compared 
with my own observations, Enalus acoroides seems also 
sometimes to be like Cymodocea æquorea. 
The Flowers«— Enalus acoroides is diceciom. Both the 
axis with the male flowers and the therewith homologous 
single female flower are surrounded by two spathe-leaves of 
partly different structure and development in both sexes. 
(PL XXIV., A fig. 1, 8). This seems to be in connection with 
the pollination in so far as their form in the female flower 
helps to keep the flower floating, and especially to give it that 
horizontal exposure, which plays an important part in the 
pollination and particularly in the catching of the male 
flowers, as will be shown below. 
The Male Flower —-The spathe-leaves of the male inflores¬ 
cence (PI. XXIV., A fig. 1) are widely ovate-lanceolate and 
somewhat keeled just like the female spathe-leaves. Their 
length does not much exceed 5 cm. Their breadth is about 3 
cm., or perhaps a little more. At the base one of them 
overlaps the other with both margins. The breadth of the 
whole spathe at the time of the anthesis or discharge of the 
male flowers is about 25 mm. Both during the early stages. 
