ON APONOGETON. 403 
simple-spiked species had been referred by Endlicher. This 
paper was, owing to my departure from India, unfortunately 
so misprinted as to be totally unintelligible ; and I have there- 
fore determined to republish it here; but to make it more 
complete examined all the species contained in Sir W. J. 
Hooker’s Herbarium, to which, as well as to some drawings 
by his son, Dr. J. Hooker, he gave me most liberal access. And 
in the Edinburgh Botanic Garden I obtained flowers, fruit, 
and germinating seeds of the A. distachys, which showed 
that it likewise is endogenous and resembles A. monostachys 
exactly in the formation of the seed ; consequently that species 
may be restored to Aponogeton. 
. The character of Quvirandra, as drawn up by De Caisne 
and published in De Lessert’s Icones, would, witha few 
trifling alterations, accurately include the Aponogeton undu- 
latus of Roxburgh. : 
The structure of the seed is very different between the 
above species, A. (Ouvirandra) undulatus has a large folia- 
ceous cotyledon, which embraces a plumule of unusual size 
and development, while in A. monostachys (and distachys) 
the seed is a homogeneous “mass, without any discernible 
Plumule till the commencement of germination, when it 
Appears protruded from a slit at the base of the long, horn- 
like cotyledon. Moreover, the former (undulatus) has sub- 
Merged and ulvaceous leaves, caducous sepals, and acutely 
elliptic pollen, while the latter (monostachys) has herbaceous 
leaves, persistent sepals, and the pollen gibbously ovoid. 
If these latter distinctions extend to the other species, as 
Sy range themselves into two groups according to the 
Structure of their seed, they may be considered of generic 
Importance; otherwise the Madagascar Ouvirandra must be 
united to Aponogeton; which would then form an assem- 
of water plants with tuberculous roots (generally edible) 
and spadicose inflorescence. If Ouvirandra and Aponoge- 
‘on be retained separate, as I should be inclined to do, they 
ach would contain plants with simple and bifurcate spikes. 
