222 WOLFFIA ARRHIZA IN ENGLAND. 
W. Brasiliensis (Weddell) is thought by Dr. Welwitsch to be a form 
of arrhiza ; this may be so, but authentic specimens look very distinct 
from our plant, the raised nodules on the epidermis being quite evi- 
dent in the dried plant. 
The characters of the British species may be thus given :— 
Frond i-i line long, j-j line broad. Upper surface more or less 
convex or nearly flat, elliptic or subrotund in outline, bright-green ; 
under surface globose, spongy, pale green; on a side view the frond 
almost as deep as long, semitransparent. Gemmiparous. The bud 
single, arising within the parent frond and ultimately bursting 
through the epidermis at the base of the extremity of its long 
axis, then invaginated by a circular projecting entire rim, which, 
when the young frond is separated from its parent, forms a cup- 
shaped fossa. Perfectly rootless. Flowers not yet seen in Britain. 
GEOGRAPHICAL Dssrrisution.—Zwrope: Portugal, abundant, Wel- 
wilsch!; France, Duchesne, etc.; Corsica, Bertoloni; Italy, Mi- 
cheli; Switzerland, Suter ; Belgium, Le Jeune; Holland, Hoffmann ; 
Germany, Bwluheim ! ; England. Asia: (*JF. Delilii, Schleid.") 
Bengal, Roxburgh, de Eastern Java, Miquel. Africa: Angola, 
Welwitsch !, abundant and profusely flowering ; Egypt?, Schleid. 
merica : New Orleans!, specimens in Kew He rbarium, dried 
amongst Lemna minor, and not nam 
Though this minute plant has so atendad a range, it probably re- 
quires a considerably high temperature, and is nowhere in Europe 
very abundant except in Portugal and the South of France. T believe 
the other European stations are mostly isolated ones. It is remark- 
able that the plant has never been seen in flower in Europe 
It is quite unnecessary to enter heré into any account of the phy- 
siology, anatomy, economy, and mode of reproduction of this interesting 
species. An excellent account of all this will be found in Hoffmann’s 
paper already referred to. Weddell (loc. cit.) has given a full description 
of the flowers and fruit of W. Brasiliensis, and an account by Hegel- 
maier of flowering specimens of JF. arrhiza, collected for the first time 
by Dr. Welwitsch, in Angola, will be found in this Journal (vol. iii. 
p. 110). 
Several figures of our plant can be quoted, the original one of 
Micheli (loc. cit. tab. 11, fig. 4) is very fair, and Hoffmann’s nearly 
all that can be desired. Franchet (ioc. cit.) has figured the mode of 
