204 CLI, LEMNACEE (BROWN). | Wolffia. 
Frond with a colourless process from the lower edge of 
the bud-cavity. 
Frond always distinctly denticulate on the margin ; 
colourless process about 4 times as long as the 
frond and not half as broad. ‘ c . lL. W.repanda, 
Frond entire, or occasionally denticulate ; colourless 
process about twice as long as the frond and 4 
as broad : : : : 4 - . 2. W. Delilit. 
Frond without a colourless process. 
Frond 2-3 lin. long, very thin, pellucid, undulated . 3. W. Welwitschit, 
Frond minute, }~4 lin. long, thick. 
Frond nearly as broad as long, flattish above . 4 W. Michelii. 
Frond much longer than broad, convex above . 5. W. cylindracea. 
1. W. repanda, Hegelmaier in Journ. Bot, 1865, 113, Frond 
minute, 4 lin. long, } lin. broad, elliptic-oblong, thin, flat above, con- 
vex beneath (convex on both sides, ex Welwitsch), denticulate on the 
margin, producing from the lower edge of the cavity from which the 
young frond emerges a flat linear colourless process, resembling a root, 
about 4 times as long as the individual fronds. Flower in the centre 
oe see 
_ ower Guinea. Angola: Loanda; plentiful in deep ponds near Bemposta, 
mixed with Lemna paucicostata, Hegelm., Welwitsch, 205! 
In two of Hegelmaier’s figures and in that of Engler & Prantl’s Pflanzenfamilien, 
the curious root-like process is erroneously represented as arising near the middle of 
the undersurface of the young frond; this is never the case. This process 3s," 
reality, nothing more than the stalk tkat attaches the young frond to its parent, 
which, after their separation, elongates in a remarkable manner to fully 4 times the 
length of the frond, and somewhat resembles a root, but hus no root-cap, and cannot 
in any sense be regurded as a root. 
2. W. Delilii, Schleid. in Linnea, xiii. 390. Frond very small, 
1 lin. long, } lin. broad, elliptic or elliptic-oblong, thin, flat, very 
obtusely rounded at the end, entire or occasionally minutely denticulate, 
producing from the lower edge of the cavity from which the young 
frond emerges a broad flat linear colourless process, about twice as long 
as the individual fronds, and 3 as broad. Flower seated in the uppe? 
surface of the frond a little to one side of the middle, and nearest, the 
basal end, according to Hegelmaier’s figures.—Kunth, Enum. 1. 4. 
W. hyalina, Hegelmaier, Monogr. Lemn. 128, t. 4, figs. 11-19, and in 
Engl. Jahrb. xxi. 301; Engl. PA. Ost-Afr. C. 423; Engl. & Prantl, 
Pflanzenfam. ii. iii, 164, and 154, fig. 101, F,G; Durand & Schinz, 
Conspect. Fl. Afr. v. 485. Lemna hyalina, Del. Fl). Aigypt. 27. 
Wile Land. Darfur: Surudj district, in fresh-water pools on Gebel Barkin, 
Pfund (ex Hegelmaier). Kordofan : Bara, Pfund, 235! 
