THE MAS GROVE OF THE BOMBAY PRESIDENCY. 647 



on account of its club-shaped lower end, the radicle will fall perpendi- 

 cularly into the mud, and by means of the terminal point it easily bores 

 a hole into the soft substratum, where, after a few hours already, you 

 can find the secondary roots. In spite of this highly practical con- 

 trivance the radicles may be found washed up in quantities all along 

 the sea-shore ; but even then they are able to grow roots in any 

 suitable place, because the lower portion of the radicle shows positive 

 and the upper one negative geotropism. 



The young mangrove plant is very circumspect during the first period 

 of her detached youth. The epicotyl grows rather slowly in the begin- 

 ing, and it is well that it does so, for a premature development of leaves 

 and branches before the young shrub has formed a strong, resistent 

 root system, adapted to its surroundings, could only end in an early des- 

 truction. For the same reason there do not appear any leaves before 

 the stem, consisting of long internodes, reaches the high- water level. 

 As soon as the stem bears branches, there is visible, just 

 above the ground, the formation of the first aerial roots. They 

 do not appear at an earlier period, as there is no need of them, for 

 a thin elastic shoot, being devoid of leaves, does not offer a 

 large surface to the action of the dashing waves. A median 

 longitudinal section of the fruit exhibits some further peculiar- 

 ities (Fig. 2, Plate A). The two cotyledons are grown together to 

 form a strange structure, the upper part of which is conical and serves, 

 as Haberlandt explains it, as an absorbing organ, through which the 

 embryo receives the necessary food-materials during the rapid growth 

 of the radicle. Behind the conical portion there follows an enlargement 

 of the cotyledons which, most probably, prevents the falling off of the 

 hypocotyl, which in the course of a short time increases rapidly in weight. 

 The continuation of the cotyledons through the micropyle andca. ^ to 1 

 in. beyond it is a tubular vagina which surrounds the epicotyl and is at 

 the same time an impediment of the upward growth of the embryo 

 before the radicle falls off. 



Another species of Rhizophora which is found in the same localities 

 as the preceding, but is not nearly so common, is Rhizophora canjugata. 

 It is a glabrous shrub or small tree with elliptic- lanceolate, coriaceous 

 leaves, dark-green above, paler beneath. The calyx is externally rugose 

 and glabrous, the petals white and glabrous. The conical or obclavate, 

 glabrous fruit is smaller than that of Rhizophora mucranata, being only 



