92 XXI. LEMNACES. [Lemna 
Quilunda near Prata, growing with Pistia, Nymphees, etc. 14 Sept. 
1854. Somewhat scarce among fronds of Azolla pennata R. Br. 
(Welwitsch herb. No. 37) in lakes in the Libongo district, on the left 
bank of the river Lifune. Sept, 1858. No. 213. ‘ 
MossaMEDES.—Fronds obovate-elliptical, with a short but evident 
longitudinal keel on the upper surface. Anthersdidymous. Plentiful 
in deep ponds at the mouth of the river Girafil and near Aguada. In 
fl. 18 July, 1859. No. 207. 
2, WOLFFIA Horkel ; Benth. & Hook. f. Gen. Pl. iii. p. 1001. 
1. W. cylindracea Hegelm. Lemnac. p. 123, t. 1, figs. 14, 15 
(1868), and in Engl. Bot. Jahrb, xxi. p. 302 (1895). 
Telmatophace cylindracea Welw. ex Hegelm. Lemnace. Lc. 
Lisonao.—Floating, densely gregarious, deep green, shining, root- 
less ; fronds cylindrico-elliptical, somewhat convex on both faces, the 
longitudinal diameter twice the transverse, apices somewhat obtuse ; 
offshoots growing out at the ends of the longitudinal diameter of the 
frond from its southern axis. Flowers and fruit vainly sought. In 
rocky pools on the mountains behind the Banza de Libongo, in the 
purest, freshest drinking-water, where no other water-plant grows. 
Sept. 1858. No. 212. 
2. W. Michelii Schleid. Beitr. Botan. i. 229 (1844). 
W. arrhiza Wimm. FI. Schles. 1857, p. 140; Hegelm. in Journ. 
Bot. 1865, p. 118, Lemnac. p. 124, and in Engl. Bot. Jahrb., ic., 
p. 301; Durand & Schinz, Consp. Fl. Afr. v. p. 485. 
Barra Do DanpE.—Plentiful and gregarious in lakes on the left of 
the river Dande, near Bombo, about 8 geographical miles from the 
river mouth. In fl. end of Sept. 1858. No. 210. 
IcoLto & BeNnGo.—Lagoa de Quilunda, near Prata, along with Pistia 
and Nympheex. Found in such enormous quantities that it is collected 
in baskets with the Pistia, which is as plentiful, and used as manure. 
14 Sept. 1854. No. 211. 
3. W. repanda Hegelm. in Journ. Bot., /.c., Lemnac. p. 129, t. 4, 
figs. 20-30, and in Engl. Bot. Jahrb., J.c.; Durand & Schinz, dc. 
Loanpa.—F ronds oblong-ovate or ovate, a little larger than those of 
LL. minor, convex on both faces, bearing near the edge on the lower 
face a process twice as long as the frond. Flowers on the back of the 
frond as in W. arrhiza. Plentiful, mixed with Lemna paucicostata 
in deep ponds near Bemposta. In fl. and fr. March 1854. No. 205. 
(in part). 
4, W. Welwitschii Hegelm. in Journ. Bot., ic., p. 114, Lemnac. 
p- 130, t. 4, figs. 1-10, and in Engl. Bot. Jahrb., d.c., p. 300. 
W. conguensis Welw. ex Trimen Journ. Bot. 1866, p. 221. 
AmbBriz.—Fronds large for the genus, exceeding Lemna polyrrhiza in 
diameter, very thin, pale green, pellucid, rootless, sometimes floating, 
sometimes resting on the river mud. Flowers on the back of the leaf 
asin Wolffia arrhiza, but fruit sought in vain. Growing with other 
species of the Order, and with Nymphzew in the lakes of Quizembo, 
and in sluggish streams near Ambriz. In fl. but without fr. Nov. 1853. 
No. 209. 
