APONOGETON. 203 
ed remarkable differences between Spathium monostachyum 
and S. undulatum, in which the plumule is highly developed 
and lodged in the bosom of a fleshy foliaceous involute coty- 
ledon, a remarkable circumstance in monocotyledonous em- 
ryos. 
Mr. Edgeworth has likewise pointed out curious differences 
between the two plants, in the submerged pluvceous habit of 
S. undulatum, and its persistent bracts, to which may be added 
some difference in the pollen, so that my friend is inclined to 
consider it as worth ranking distinctly under the name Lim- 
nogeton. 
APONOGETON. 
Aponogeton monostachyum. Stoloniferum. Carpella alba 
ventricoso-inflata cellulosa, demum spontanea in farina solu- 
bilia. Stylo rostrato. 
Semina pauca ascendentia, oblonga, cellulosa viridia 6-8 
costata, hilo indistincte, foramine hiloque propinquis, aunulo 
circumcinctis. 
Embryo orthotropis, viridescens, radicula brevi albida, plu- 
mula albida inclusa fere omnino. 
Testalaxa simplice striata. Tegument interius embryo- 
nam? apice mammillatam e striatis vel exterius cellulis, inte- 
rium quasi mucilaginos. 
Stomata upper surface in vast abundance to be seen iu all 
stages, open or shut, when shut, the disc is linear opaque, when 
open the disc is oval with irregular opaque margins. Seram- 
pure Oct. 28th, 1841. 
