LE>rNACEj^. 17 



Section L— STAUROGETON. Reich. 



Fronds submerged, translucent, at length tailed, each giving rise to 

 a single root-fibre, and furnished with naked lateral clefts from which 

 young fronds are produced, which remain permanently attached to the 

 parent frond; epidermis absent. Flowers from a cleft in the margin 

 of the frond. Ovary containing a single semi-anatropous ovule. 

 Fruit 1-seeded, indehiscent. 



SPECIES I.— L E M N A T R I S U L C A. Linn. 



Plate MCCCXCIV. 



Beicli. Ic. Fl. Germ, et Helv. Vol. VH. Tab. XV. Fig. 18. 

 Billot, Fl. Gall, et Germ. Exsicc. No. 2384 



Fronds submerged, translucent, thin, flat, elliptical-lanceolate, 

 crenate-seiTate towards the apex, the yoxmg fronds at length tailed, 

 and attenuated into a stalk, by which they remain attached to the 

 parent frond, each frond giving rise to a single root-fibre. 



In ponds and ditches. Rather common, and generally distributed 

 in England. Rare in Scotland, where it is reported only from the 

 counties of Berwick, Roxburgh, Edinburgh, Fife, and Forfar. Local, 

 but widely distributed in Ireland. 



England, Scotland, Ireland. Perennial. Spring, early Summer. 



Fronds :! to i inch long, not including the tail, wliich sometimes 

 attains the length of ^ or even ^ inch. The young fronds spring at 

 right angles from the sides of the parent frond, and remain connected 

 with it ; from these other fronds are at length given ofi^, so that we 

 have at last a group of fronds, all tailed or stalked, excejDt those last 

 produced. The fronds in this, as in the other species of the genus, are 

 said to be annual, but I have found the old fronds in February: 

 whether they die wholly away before the new fronds attain any size, I 

 am unable to say; but I suspect they do not, and escape observation in 

 winter from Ipng in the mud at the bottom of the water. The frond, 

 with the young ones proceeding from it, before the stalks of the latter are 

 developed, appears hastate with 3 neai'ly equal lobes, in which it diifers 

 from all the other British species. The flowers I have never seen. 

 They are figured by Reichenbach as coming from clefts situated about 

 the place where the young fronds ought to be given off; i.e. nearer 

 the tailed end of the fr'ond than the apex. 



Ivy-leaved Duckweed. 



French, Lenticule prolifere. German, Dreifurchige Wasserlinse. 

 Althongh pretty enongh to excite general interest, we have nothing to record of the 

 nse.s of the species of Lenina. Their popular name of Duckweed is given in allusioa 

 VOL. IX. D 



