century before the arrival of the Spaniards. It is asserted that the Hand-tree grows wild in the forests of Guatimala.[OI] We found two Malvaceæ, _Sida Phyllanthos_ (Cavan.), and _Sida Pichinchensis_, rising in the equatorial region to the great height of 13,430, and 15,066 feet on the mountain of Antisana and at the volcano of Rucu Pichincha.[OJ] The _Saxifraga Boussingaultii_ rises from 600 to upwards of 700 feet higher, on the declivity of Chimborazo. Footnote 88: p. 225—“_Form of the Mimosæ_.” The delicate and feathery foliage of the Mimosæ, Acaciæ, Schrankiæ, and Desmanthus, may be regarded as peculiarly characteristic of tropical vegetation; although some representatives of this form may also be found without the tropics. In the Old Continent of the northern hemisphere, and indeed in Asia, I can instance only one low shrub, described by Marshal von Bieberstein as _Acacia Stephaniana_, but which, according to Kunth’s more recent investigations, is a species of the genus _Prosopis_. This social plant covers the arid plains of the province of Schirvan on the Kur (Cyrus), near New Schamach, as far as the ancient Araxes. Olivier found it also in the neighbourhood of Bagdad. It is the _Acacia foliis bipinnatis_ mentioned by Buxbaum, and which extends towards the north as far as 42° lat.[OK] In Africa the _Acacia gummifera_ (Willd.), extends to Mogador, and therefore as far as 32° north lat. In the New Continent, _Acacia glandulosa_ (Michaux), and _A. brachyloba_ (Willd.), adorn the banks of the Mississippi and Tennessee, and the Savannahs of the Illinois. The _Schrankia uncinata_ was found by Michaux to penetrate from Florida northwards to Virginia (therefore as far as 37° north lat.). _Gleditschia triacanthos_ is met with, according to Barton, to the east of the Alleghany mountains, as far as 38° north lat., and west of the same range even to 41° north lat. The extreme northern limit of _Gleditschia monosperma_ is two degrees further southward. Such are the boundaries of the Mimosa form in the northern hemisphere, while in the southern hemisphere, beyond the tropic of Capricorn, simple-leaved Acaciæ are found as far as Van Dieman’s Land; the Acacia cavenia described by Claude Gay being even found in Chili between 30° and 37° south lat.[OL] Chili has no true Mimosa, but three species of Acacia; and even in the north of Chili the Acacia cavenia grows only to a height of 12 or 13 feet, whilst in the south, as it approaches the sea-coast, it scarcely rises a foot above the ground. The most sensitive of the Mimosas which we saw in the northern portion of South America, are (next to the Mimosa pudica,) _M. dormiens_, _M. somnians_, and _M. somniculosa_. The irritability of the African sensitive plant was already noticed by Theophrastus (iv. 3), and by Pliny (xiii. 10); but I find the first description of the South American sensitive plants (Dormideras) in