LEMNACE®. 17 
Section I.—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—LEMNA TRISULCA. Li. 
Prate MCCCXCIYV. 
Reich. Ic. Fl. Germ. et Helv. Vol. VII. Tab. XV. Fig. 18. 
Billot, Fl. Gall. et Germ. Exsicc. No. 2384. 
Fronds submerged, translucent, thin, flat, elliptical-lanceolate, 
crenate-serrate towards the apex, the young 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 } inch long, not including the tail, which sometimes 
attains the length of 4} 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 off, so that we 
have at last a group of fronds, all tailed or stalked, except 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 lying 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 nearly equal lobes, in which it differs 
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; ie. nearer 
the tailed end of the frond than the apex. 
Ivy-leaved Duckweed. 
French, Lenticule prolifére. German, Dreifurchige Wasserlinse. 
Although pretty enough to excite general interest, we have nothing to record of the 
uses of the species of Lemna. Their popular name of Duckweed is given in allusion 
VOL. IX. D i 
