LEMNACEAE 240 
LFFIELL A Hegelmaier. 
E. -body thin, dui shaped or sabre- 
orm. Pro dx gative iw cea 
Inflorescence and fru unkno 
About 7 en mostly H e dis 
tribution. 
1. W. ge ana (J. D. Smith) C. 
Thompso Plants solit itary or usually 
several pole tok cohering; body ` at- 
tenuate from the base to the slender apex, 
0 mm 
Stagna: ant Dn hs ‘Plain and adj. 
and N. 
provinces, Fla. ex. Mo. J. 
3. LEMNA L. Plant-body disk-like, d nerved. Anther- 
sacs opening transversely. Utricle somewhat flattened, often ribbed.— 
out 8 species, Mind distributed in tropical e temperate regions Wen 
EDS. PFROG-BUTT 
Plant-bodies long-stipitate, forming large submerged masses. 1. L.trisulca. 
Pla Eo sessile, or short-stipitate, floating, more or less de- 
Plant-body symmetrical or nearly s 
ant-body elliptic-obovate : Teac lenticular. 
2. L.m 
Plant body e d oblong: utricle elongate. 3. L. 
mind: 
Plan nt-body-thiek, panum obovate, papillose on the me- 
4. L. perpusilla. 
Plant-body thi in, elliptic, smooth. 
Pla eek e a 3-nerved : root-sheath with lateral 
5. L. trinervis. 
Pintbod O 1-nerved: root-sheath without ap- 
ages. 6. L. cyclostasa. 
lca L. Root-sheath acute: 
plant- "bodies both ooo and aerial, 
often falcate, 5-10 mm. long, acute: 
aerial p smaller than ‘the submerged 
a submerge 
spring-runs, various provinces, Ala. to 
Calif., Alas., Ont., and N. S.—(0. W.) 
2. L. L.  Root-sheath - m 
plant- bodies elliptic, obovate, 
orbicular, 2—4 mm. long, m mostly oer ee. 
commonly keeled on p back and papil- 
lose on the midrib: seeds 12—165-ribbed. 
.—Ponds and "redii. water, various 
provinces, Fla. to Calif., B. C., and Ont. d 
—(0. W.) 
3. I. minima Philippi. Root-sheath obtuse: sigue body oblong or elliptic, 1.5— 
3.9 mm. long, rounded at the apex, sometimes slightly oblique, nearly nerveless, 
