LEMNACEAi—DUCKWEED TRIBE 23 
the eye. These are the anthers, and they being found, you have only to 
carry home the plants, and place them under the microscope, when all the 
secrets of their flowering stand revealed. Where the anthers have caught 
the eye will be seen a narrow slit, out of which they peep; if you widen 
this slit with your dissecting instrument, you will be able to extract the 
- blossom entire, and you will have before your eyes the simplest of all known 
flowering plants. The flower consists of a transparent membranous bag, 
shaped like a water-caraffe, and split on one side; within it are two stamens 
and one ovary, with a style and simple stigma.” 
What Dr. Lindley here describes as the flower is really the spathe, each 
stamen representing a separate flower. Enlarged representations of the 
inflorescence of this and other species are given on our plate, beside the 
enlarged figure of the plant. 
Country people still frequently call the Duckweed Water-lens. Gerarde 
terms it Water-lentils, and adds, that the Dutch call it Weerlinden. He 
names it also as the Duckweed, and gives a curious engraving, in which the 
ducks appear to be luxuriating upon it. 
2. Ivy-leaved Duckweed (L. trisiilca).—Fronds thin, between elliptical 
and lanceolate, serrated towards one end, and tailed at the other ; roots 
solitary. This plant is not unfrequent on clear waters, chiefly in England 
and the Channel Islands ; in Ireland and Scotland it is rare. Its fronds are 
green, and clear at the margin, half an inch or more long, bearing each a 
root, which is tipped with a little cap or sheath. This sheath is found to be 
an especial organ, formed before the root bursts forth. The form of this 
Duckweed is very different from that of any other species; and Linnzus 
remarked that its flattened fronds producing new plants, and crossing each 
other, resembled in their mode of growth the Opuntia, or Indian fig. It is a 
common species on ponds and lakes. 
3. Gibbous Duckweed (ZL. gibba).—Fronds inversely egg-shaped, hemi- 
spherical beneath. This plant is larger than the Lesser Duckweed, green 
above, and distinguished by its bulging lower surface, which is white and 
clear. It floats in ditches, pools, and lakes, flowering from June to Sep- 
tember. 
4, Greater .Duckweed (L. polyrhiza).—Fronds broadly egg-shaped, 
somewhat convex beneath; roots numerous. This is the largest of our 
native Duckweeds, and has thick firm fronds, about half an inch long, and 
almost as broad. The under part is tinged with purple, and the upper side 
is marked with seven nerves. The plant is rare on our stagnant waters; in 
Scotland it occurs locally, but is a doubtful native. It is, like all our Duck- 
weeds, an annual, sinking in winter to the bottom of the pool. 
2. WoLFFIA (/Volffia). 
Wolff's Duckweed (W. arrhiza).—Frond oblong, loosely cellular 
beneath ; root absent. This species has the distinction of being the smallest 
flowering plant at present known to science. Seeing that the longest measure- 
ment of the frond is only one-twentieth of an inch, and its breadth half that 
dimension, a rival for this honour is not very likely to be discovered. Until 
1886, when it was discovered by Mr. H. Trimen, it had been quite overlooked 
