200 NAIADES. 
its base which is contiguous to the foramen is more transpa- 
rent than the rest, and is somewhat conical, and this appears 
to be considered by Hooker as the radicle. 
Examination of germinating specimens can only clear up 
which part of this immense radicle first germinates. All 
analogy would teach us that its true apex is the first part 
that undergoes any change. And the resistance of the drupe 
being overcome, that of the coats of the seed is[[wuts os 
that there is but little ground for assuming that any extra- 
ordinary change in this respect would occur. The change 
in the direction of part of the seed is in accordance with the 
structure of the order? Ruppia is I believe a new addition 
to the Flora of India, and it is an additional instance of the 
fact that the flora even of Calcutta, is by no means exhausted. 
Of the fourteen genera of this family enumerated in Lind- 
ley's Introduction. India possesses, Caullinia, Naias, Potama- 
geton, Zanichellia and Ruppia. To these are to be added 
Ceratophyllum, Potamogeton is the most perfect in number 
of parts, and of species. 
It belongs to an order in which the extremes of geogra- 
phical distribution occurs. Whether this depends on the 
habits of the plants, or on their low organisation, (shewn by 
their comparatively small number of species,) remains to be 
shewn. It is a curious thing that some of the species are 
decidedly marine plants, thus forming an obvious approach to 
Algz, as Thalassia marina, Zostera, Cymodora, Posidonia. 
Ruppia, Pl. CCLVIII. 
1’, Spadix, and the termination of axis. 
2’. Same more enlarged, leaves spread out, а spatha, 
3. Spadix detached. 
4. Back view of anther, 
5. Lateral ditto ,* 
6,6. Pollen. ба, burst by pressure yds. 6, fovilla. 
7. Inner of anther, shewing the rudimentary fibres of cells. 
