30 LEMXA. [class II. ORDER I. 



2. L. polyrrln'za, (Fig. 41.) greater Ducktveed. Fronds ovato-rotun- 

 date compressed, roots numerous in clusters. 



English Botany, t. 2458. — English Rora, vol. i. p. 33. — Lindley, 

 Synopsis, p. 252. — Hooter, British Flora, vol. i. p. 13. 



The largest of the genus, and well distinguished by its clustered 

 roots gi-owing from the point of union Mhere the fronds unite. Fronds 

 about half an inch long, and nearly as broad, striated above with a 

 dark purple margin, somewhat convex beneath, of a purple colour. 

 Flou-ers not known in Britain. " Wiggers records a young German, 

 named Graver, as having found the flou-ers, situated where the fronds 

 overlay each other, in July and August. The seed proved larger and 

 flatter than in L. r/ibba." — Smith. 



Habitat. — Ditches and pools, not common ; Nottingham meadows. 



Annual. 



3. L. gib'ba, (Fig. 42.) gibbous Ducktveed. Fronds broadly obovate, 

 slightly convex above, hemispherical, and pale beneath, roots soli- 

 tary. 



English Botany, t. 1233.— English Flora, vol. i. p. 32.— Lindley, 

 Synopsis, p. 2.52. — Hooker, British Flora, vol. i. p. 13. 



Larger than L. minor. Fronds green above, in a young state flat, 

 pale beneath, and gradually swelling until almost hemispherical, first 

 commencing to swell at the base of the root, until at length the en- 

 larged pellucid cellules burst; the fronds then turn yellow, and shortly 

 decay. Roots solitary. Flowers from tlie margin of the frond, j)eri- 

 anth scarcely visible. — This species somewhat resembles L. minor, but 

 is readily distinguished by its large cellular and gibbous, or hemisphe- 

 rical under surface. " Capsule four-seeded. Seed fun'owed, not 

 transversely placed, but with the hilum towards the top of the cap- 

 sule."— Wilson in Br. Fl. 



Habitat. — In stagnant waters, not so common as the following spe- 

 cies. 



Annual ; flowering from June to September. 



4. L. mi'nor, (Fig. 43.) lesser Duckweed. Fronds nearly ovate com- 

 pressed, slightly convex beneath, roots solitary. 



English BotJiny, t. 1095. — English Flora, vol. i. p. 32. — Lindley, 

 Synopsis, p. 2.52. — Hooker, British Flora, vol. i. p. 13. 



Fronds from one to two lines' long, irregular, plane or slightly con- 

 vex above as well as beneath, where it is of a pale colour, somewhat 

 fleshy, and of a more compact texture than L. gibba. Flotrers similar 

 to the last. " The capsule is single-seeded ; seed transverse, with its 

 hihim ' directed towards the narrow end of the frond.' " — Hooker. — 

 This is the most common of all the species, increasing with great rapi- 

 dity by gemmfe or buds, frequently covering the surface of extensive 

 pools of stagnant water, and often considered a troublesome intruder 

 in fish-ponds. Ducks and other water-fowl feed upon it, hence 



