WOLFFIA ARRHIZA IN ENGLAND. 219 
tisve apice acuminatis acutis basi rotundatis supra glabris subtus ad 
nervum centralem subtilissime puberulis siccis membranaceis, centrali 
nervo ad apicem dueto ad apicem utrinque nervos 8-10 patulo-subad- 
scendentes vel apicem versus venas fortiores mittente, pedunculo petio- 
lum equanti, amento quam folium triplo breviori sublaxifloro, rachi 
dense molliter hirtella, bractea breviter pedicellata apice saccato-galeata 
acuta dorso subtiliter hirtella.—In Brasilia (Sellon, Herb. Reg. Ber. 
n. 228).— Frutex, ramuli glabri, nodi tumidi, foliorum limbi 0,12 longi 
0,035 lati, petioli 0,003 longi. : 
P. Francovilleanum ; folis brevissime petiolatis subovato-ellipticis 
apice protracto-acuminatis acutis basi inzequaliter rotundatis latere 
maj. aurieulatim producto supra glabris subtus ad nervum centrale 
villosis margine ciliatis siccis rigidulo-membranaceis, centrali nervo ad 
apicem ducto ad apicem nervos utrinque 20 alternos venasque fortiores 
patulo-adscendentes mittente, peduneulo petiolum multot. superanti, 
amento quam folium triplo breviori deusifloro, rachi villosa foveolata, 
bractea prope florem inserta lanceolata.— In Brasilia prope Barra 
(Spruce, n. 1784, Herb. Francov.) et San Gabriel da Cocheira ad Rio 
Negro (Spruce, n. 2362, Herb. Cand.).—Fruticulus simplex apicem 
versus dense villosus, nodi tumidi, foliorum limbi 0,2 longi 0,085 
lati, petioli 0,005 longi. 
WOLFFIA ARRHIZA, Winner, IN ENGLAND. 
By Henry Trimen, M.B. Lonp., F.L.S. 
Th 
subject of this article has been hitherto overlooked in England, though 
now that attention is drawn to its existence here, it is likely to be 
found in many places within our boundary. 
The locality where I detected this—I suppose our smallest phane- 
rogamous plant—is a pond near Staines, Middlesex. It grows in 
abundance there, floating on the surface of the water between the 
fronds of Lemna polyrrhiza, L. gibba, and L. minor. 
The genus Wolffia (named after Johann Friedrich Wolff, author of a 
