38 MISSOURI BOTANICAL GARDEN. 
Closely related to W. gladiata Hglm., of Mexico, but 
differing in its constantly more narrow form, long flagellate 
apex, proportionately broader base, in being more cavern- 
ous, and having fewer and larger punctations. 
Specimens examined from Georgia (Waite) ; Florida (Ravenel, 1877; 
Smith and Austin, 1878; J. D. Smith, 1878-80; Curtiss, no. 2699, 1881; 
Swingle, no, 71, 1892; Nash, no. 254, 1894); Missouri (Eggert; Bush, 
1895; Widmann, 1895; Trelease, 1897); Arkansas (Eggert, 1892); Louis- 
iana (Dr. Hale, about 1880-40); Texas (Joor, about 1877). 
WOLFFIELLA oBLoneA (Ph.) Hglm. Engler’s bot. Jahrb. 
21°: 303. Jan. 1895. Lemna oblonga Philippi, Lin- 
naea. 29: 45. 1857. Wolfia oblonga (Ph.) Hglm. 
Monogr. Lemnac. 131. 1868. W. lingulata Hglm. 
var. minor Hglm. Lemnac. in Martius Fl. Bras. 3?: 
10. Feb. 1878. 
Fronds at maturity solitary or in pairs, rarely three 
cohering; long oblong or commonly gradually tapering 
from the obliquely rounded base to the slightly narrower 
bluntly rounded apex; slightly faleate, rarely nearly 
straight ; basal portion alone exposed to the air; .53-1 mm. 
broad by 1.7-4.6 mm. long, about 3-5.5 times as long as 
broad. Reproduétive pouch isosceles-triangular with the 
base a little narrower than the sides. Stipe scar small, 
blunt, rounded, situated at the lowerright-hand juncture of 
the two walls of the pouch, conspicuous from the cluster of 
pigment cells it contains.— A Mexican and South American 
species, at present reported from but one locality in our 
range.— Plate 4B, 
Hegelmaier* was in doubt as to the advisability of 
separating this species from W. lingulata on the ground of 
the striking similarity of his W. lingulata var. minor to 
W. oblonga. My examination of a number of collections, 
both from Mexico and South America, prove beyond a 
doubt in my mind that his variety is not one of W. lingu- 
lata but merely an elongated form of W. oblonga. In the 
* Hegelmaier, Friedr. Systematische Uebersicht der Lemnaceen. 
Engler’s bot. Jahrb, 213: 303-304. Jan. 1895. 
18 
