FLORA OF NORTH-WESTERN MEXICO. 285 
The tTvo Myrf(iC€(S from Mexico, enumerated by Hooker and Arnott, are also too imperfect to be made 
out; if one of them be Myrfus communis, it must be cultivated. 
CUCURBITACEiE. 
213. Bryonia atienuata, Hook, et Am. Bot. Beech, p. ^%4..~Anguria ? dubia?, Hook, et Am, 
1. c. p. 294 ! Tepic and Acapulco (Lay and Collie !}. 
214. MoMORDicA Bahamina, Linn., De Cand. Prodr. vol. iii. p. 311. Tepic (Lay t). 
215. LuFFA quinquejida, Seem. — Elaterium quinquefidumj Hook, et Am. Bot. Beech, p. 292. 
Acapulco (Lay and Collie ! Sinclair !) 
216. SicYos vitifoUuSj Hook, et Am. Bot. Beech, p. 292, et Willd.? Tepic (Lay!). 
217. Gronovia scandens, Linn., De Cand. Prodr. vol. iii. p. 320. Tepic (Lay!). 
PASSIFLORACEiE. 
{Passiflore<je ! Turnerace<B ! Malesherbiaceee !) 
218. Passiflora viridijloraj Car.j Hook, et Am. Bot. Beech, p. 292. Acapulco (Lay and Collie I). 
219. Passiflora pannosa, Hook, et Arn. Bot. Beecli. p. 293, et Sii)ith ? Talisco (Lay and 
Collie!). 
\ 
^^^ r 
220. Turnera tomentosa, H.B.K., De Cand. Prodr. vol. iii. p. 347? Tepic (Lay !). 
CACTE^. 
{Auctore F. Scheer.) 
Having furnished Dr. Secmann with letters to Mr. John Potts, manager of the Jlint at Chihuahua, we 
might have expected, from the zeal and labours of both gentlejnen, a large addition, not only to our know- 
ledge of Cactece, but of many other plants, of which that district seems to contain much as yet unknown. 
Dr. Seemann was not able to extend his journey so far north ; and, as it is not likely that other travellers 
will soon venture into a region so difficult of access and so full of perils, it appears desirable that what has 
been collected by Mr. Potts should no longer remain unpublished. 
Ever since 1842, Mr. Potts has sent mo plants almost anmially ; these were found, either by himself, 
about the city of Cliihuahua, or on short excursions from thence, or by his brother, the late Mr. Frederick 
Potts, who resided chiefly on the borders of the State of Sonora. The diiEcultics which these gentlemen 
had to contend with were not small,— personal danger from the Comanches and other tribes of Indians to 
whoever ventures beyond the immediate precincts of towns or haciendas being of constant occurrence. 
The trouble of forwarding what had been collected was considerable. Much was lost before an opportunity 
to despatch packages offered j some of these were six months or more on their way to England ; some 
never reached their destination, amongst which was a large case entrusted to an American traveller, con- 
taining, among other things, a pine-cone of an unusual size, and weighing about eighteen pounds ! A very 
large collection was brought by Mr. Potts liimself in 1850. It is also needless to add that many plants 
woidd arrive in a ver}' dilapidated condition. 
Being myself at first but slenderly acquainted with this tribe of plants, and not wishing to increase the 
confusion of nomenclature with which its study was and still is encumbered, I abstained in most instances 
