of Limnanthemum lacunosum. 7 



collected at Boston, North America, by Mr. Greene, which, 

 as they seem to afford a new example of very unequal cotyle- 

 dons, are the more entitled to particular investigation, since the 

 fuller development and the petiolar inflorescence of that genus 

 has long excited the curiosity of botanists. I was able to ex- 

 amine two germinating specimens hanging still to their seeds ; 

 but unfortunately neither was quite entire, though one, how- 

 ever, perhaps explains the other. One plant (Plate I. fig. 1.) is 

 in a very young state ; it consists of the seed, which is laterally 

 opened and encloses a small dark body, viz. one of the coty- 

 ledons, connected with the radicle by a very short petiole ; the 

 radicle is an inch long, very slender, and descends parallel 

 to the seed : opposite to this enclosed cotyledon, rises, in an 

 oblique direction, a very fine white filament, almost as long as 

 the radicle, but mutilated or torn off at its tip. In the other 

 specimen (fig. 2.), the radicle of which is very short and evi- 

 dently in an injured state, this filament is almost two inches 

 long, white, cylindrical, and scarcely half a line in diameter, 

 and ends here in an oblong body, out of which three cylindri- 

 cal long roots descend, while a petiole with its leaf and the ru- 

 diments of a second ascend from it. Though it cannot be quite 

 determined whether that oblong body has a foliaceous nature, 

 nevertheless it seems certain that it embraces the base of the 

 petiole, as well as that the roots arise from the same point : 

 therefore I cannot but consider that body as the other coty- 

 ledon, at the top of whose petiole, the germs of the new plant 

 originate. For, first, the filament, which I think to be the 

 petiole of the cotyledon, stands opposite to the cotyledon, 

 inclosed in the seed, and has that situation towards the 

 radicle, which cotyledons always have in exogenous plants. 

 Secondly, Trapa affords a similar instance of unequal coty- 

 ledons. Thirdly, the more advanced vegetation of Limnan- 

 themum shows the strongest analogy with such a formation 

 of petiolar development as that alluded to; namely, the 

 seed and its filament being obliterated, more and more roots 

 and leaves grow from the same point (fig. 3.), till one petiole 

 attains a much greater length than the others (fig. 4.) ; this 

 petiole, commonly half a foot high, while the rest are scarcely 

 more than an inch, develops soon, not far from the origin of 



