n, 'De l'Espece,' p. 462.

[516] Quatrefages, 'Etudes,' &c., pp. 12, 209, 214.

[517] Robinet, 'Manuel,' &c., p. 303.

[518] Robinet, idem, p. 15.

[519] 'Geographie Botanique Raisonnee,' 1855, pp. 810 to 991.

[520] Review by Mr. Bentham in 'Hort. Journal,' vol. ix. 1855, p. 133,
entitled 'Historical Notes on cultivated Plants,' by Dr. A.
Targioni-Tozzetti. _See_ also 'Edinburgh Review,' 1866, p. 510.

[521] 'Hist. Notes,' as above, by Targioni-Tozzeti.

[522] 'Considerations sur les Cereales,' 1842, p. 37. 'Geographie Bot.,'
1855, p. 930. "Plus on suppose l'agriculture ancienne et remontant a une
epoque d'ignorance, plus il est probable que les cultivateurs avaient
choisi des especes offrant a l'origine meme un avantage incontestable."

[523] Dr. Hooker has given me this information. _See_, also, his 'Himalayan
Journals,' 1851, vol. ii. p. 49.

[524] 'Travels in Central Africa,' Eng. translat., vol. i. pp. 529 and 390;
vol. ii. pp. 29, 265, 270. Livingstone's 'Travels,' p. 551.

[525] As in both North and South America, Mr. Edgeworth ('Journal Proc.
Linn. Soc.,' vol. vi. Bot., 1862, p. 181) states that in the deserts of the
Punjab poor women sweep up, "by a whisk into straw baskets," the seeds of
four genera of grasses, namely, of Agrostis, Panicum, Cenchrus, and
Pennisetum, as well as the seeds of four other genera belonging to distinct
families.

[526] Prof. O. Heer, 'Die Pflanzen der Pfahlbauten, 1865, aus dem Neujahr.
Naturforsc. Gesellschaft,' 1866; and Dr. H. Christ, in Ruetimeyer's 'Die
Fauna der Pfuhlbauten,' 1861, s. 226.

[527] 'Travels,' p. 535. Du Chaillu, 'Adventures in Equatorial Africa,'
1861, p. 445.

[528] In Tierra del Fuego the spot where wigwams had formerly stood could
be distinguished at a great distance by the bright green tint of the native
vegetation.

[529] 'American Acad. of Arts and Science,' April 10th, 1860, p. 413.
Downing, 'The Fruits of America,' 1845, p. 261.

[530] 'Journals of Expeditions in Australia,' 1841, vol. ii. p. 292.

[531] Darwin's 'Journal of Researches,' 1845, p. 215.

[532] De Candolle has tabulated the facts in the most interesting manner in
his 'Geographie Bot.,' p. 986.

[533] 'Flora of Australia,' Introduction, p. cx.

[534] For Canada, _see_ J. Cartier's Voyage in 1534; for Florida, _see_
Narvaez and Ferdinand de Soto's Voyages. As I have consulted these and
other old Voyages in more than one general collection of Voyages, I do not
give preci