Lemna.'] 
civ. fistiace^:. 
477 
Embryo either in the axis of a fleshy albumen and having a 
lateral cleft for the emission of the plumule, or at the apex of 
the nucleus. — Floating frondose plants, minute and usually len- 
ticular, or with large lobed fronds. 
1. Lemna Linn. Duckweed. 
Spatha membranous, urceolate. Stain. 1 — 2, distinct, each 
bearing a 2-celled didymous anther (the cells bilocular?) 
Fruit utricular. — Fronds without distinct stem or leaves, floating 
on the surface of the water , and increasing, not only by seeds, but, 
far more abundantly, by gemmae or buds, concealed, in lateral 
clefts of the parent frond, which, growing out on 2 opposite sides 
into new plants, and these again producing offspring in the same 
way, while still attached to their parent, present a remarkable 
appearance. — Name : \tyva, of the Greeks, it is said from XtTrtg, 
a scale. 
1. L. trisulca L. {Ivy -leaved D .) ; fronds thin elliptico-lan* 
ceolate caudate at one extremity serrate at the other, roots 
solitary. E. B. t. 926. 
Clear stagnant waters. Less frequent in Scotland than in England. 
©. 6, 7. — Fronds ^ J of an inch in length, pellucid at the 
margins, reticulate. Hoots solitary, calyptrate at the extremity, as in 
most of the genus. Stamens 2. Ovary with a single ovule. Seed 
solitary, transverse, attached by a short stalk to the bottom of the 
utricle. 
2. L. minor L. ( lesser 71) ; fronds nearly ovate compressed, 
roots solitary. E. B. t. 1095. 
Stagnant waters, common. ©. 7. — About a line or aline and 
a half long, of a rather thick and succulent, but compact texture, 
slightly convex beneath. The young fronds constitute the Lemna 
arrhiza of the French authors. Stamens 2. Ovary 1-ovuled. The 
utricle is single-seeded ; seed transverse, with its hilum “ directed 
towards the narrow end of the frond : ” Wilson. 
3. L. polyrrhiza L. ( greater D.) ; fronds obovato-rotundate 
compressed, roots numerous from the same point. E. B. t. 2458. 
Spirodela Schleid. 
Stagnant waters. Rare in Scotland: near Glasgow. ©. Flowers 
unknown in Britain. — The largest of all the species, half an inch 
long and nearly as broad, succulent, firm, faintly striate, a little 
convex below, where, and at the margin above, the frond is of a deep 
purple colour. Spiral vessels are conspicuous throughout the whole 
plant ; but in all the other species there are either none, or they 
are evanescent. Stamens 2 ; filaments tapering below. Ovary with 
2 erect ovules. The mature fruit of this species has not been 
observed. 
4. L. gibba L. ( gibbous D .) ; fronds obovate nearly plane 
