206 LEMNACE. 
5. More advanced. Lower sepal and stamina, behind. 
6. Flower; 6a do. more advanced, anterior lower sepal 
removed to shew the dehiscence of the anthers, 
7. Pollen, dry 8, 8a do. immersed in water. 
9. Pistillum, the two lower sepals partly removed, and one 
upper one remaining with its anthers, one cell opened 
longitudinally shewing the situation of the ovule, and 
its direction. ; 
9a. Ovule laterally, 94 in front, 10 long section. 
11. Transverse of ovary, a ovuliferous portion. 
12. Do. more towards the apex. 
13. Fruit. 
14. Do. long section thro’ one fertile and one barren cell. 
15. Transverse of Do. shewing that the fertile cells are 
separate from the others, one cell having already se- 
parated at a. 
16. Seed. Back and side view. 
17. Seed/ long section, а outer tegument, 5 inner, с coty- 
ledon, d radicle, e Plumula, f foramina, g raphe, A 
chalaza. 
18. Embryo separated, 18 a long section of the same. 
19. Base of Embryo a front shewing the slit, 19 a do. 
slit laid open. 
20. Plumula detached, under ,*;, it appears simple. 
LEMNAC EZ. 
General Remarks. 
The diagnostic character of the genus Lemna as given by 
Achille Richard appears to me,if I may venture an opinion, to 
display a want of precision. For not only are parts assumed 
to be annalogous to other parts of other vegetables, such 
as—Herbz acaules sepius triplylle, subtus radicantes ! 
— Flores e fissure marginali foliorum orte, minimi ;—but cha- 
racters of very minor importance are also admitted, such as— 
spatha compressa reticulata pelucida.—Stamina spatha lon- 
