Podostemacea. 167 



about to leave them, the spathe remaining closed till it 

 comes into contact with the air. In this manner we find on 

 the same slanting piece of rock, and within a few inches of 

 each other, patches of these plants which have gone through 

 the whole process of vegetation and fructification, dried and 

 shrivelled up, so that scarcely a vestige of them remains, 

 along side of others which are perfecting their seeds. To 

 these succeed those which are just bursting into flower, 

 while in the deeper water, others are ready to follow them, 

 as soon as the waters have fallen a little further. The seeds, 

 which have a mucilaginous coat when moistened, are shed 

 on the rocks during the dry season among the remains of the 

 plants which produced them, and lie there till they are 

 moistened by the first rains, when they adhere firmly to the 

 spot on which they have fallen, and are thus prevented 

 from being carried away by the floods of the rainy season. 

 Vegetation is entirely carried on while they are submerged, 

 and by the next dry season the plants are ready to go 

 through all the changes of their progenitors. 



The nature of the stems, branches, and leaves of these 

 plants is very remarkable, alike in the variety of forms 

 which they assume, as in their organic structure. They con- 

 sist almost entirely of a homogeneous mass of cellular tissue, 

 and, in this respect, resemble the alga? and other low types 

 of the vegetable kingdom. Griffith, in speaking of the two 

 species which he has described says, " in neither of these 

 plants have I been able to ascertain the existence of any 

 vascular tissue, the place of which appears to be supplied by 

 fibres of very small diameter packed very closely together, 

 and, at least after maceration in spirit, filled with grumous 

 matter." Like other submerged plants they are destitute of 

 stomates. 



In systematic Botanical works, much diversity exists with 

 regard to the limitation of the genera of this natural order. 

 The genus Mourera, as modelled by Professor Endlicher, 



