180 BOTANICAL INFORMATION. 
their colours bright, and, though white and yellow are the predominant, 
those displaying other tints are by no means uncommon. Among the 
flowering plants hitherto detected, the colours are thus distributed. 
The prevailing tint of the floral envelopes is greenish-yellow in fifty- 
three species, white in fifty, yellow in thirty-six, purple in twenty-five, 
blue in fourteen, rose-colour in ten, and red in one. It is remarkable 
that red occurs in only one solitary instance, and that scarlet is entirely 
wanting. Some allowance has to be made for the first division, 
greenish-yellow, which includes all plants with imperfectly developed 
floral organs, viz., many Monocotyledones, the Amentacee, and other 
apetalous forms. Besides this, there are other discrepancies. From 
various causes, several species change their colour. Lychnis apetala, for 
instance, when growing in clay or sand, bears white, when in peat, purple 
flowers. Papaver nudicaule, also, alters its colours, of which, how- 
ever, not soil, but temperature seems to be the cause. In Kotzebue 
Sound, and other sub-arctic parts, it is yellow ; towards Point Barrow 
almost invariably white; and, if I recollect right, the specimens 
brought to England by Captain Parry, from Melville Island, as well as 
those collected by Dease and Simpson at Point Barrow, were also 
white. In another Papaveracea I noticed the same change. Argemone 
Mexicana is, around Lima and the temperate parts of Ecuador, 
white; in the torrid regions of New Granada, Central America, and 
Mexico, yellow; while at the Sandwich Islands, which enjoy a cool 
cliniate, it is again changed into white. (Are not these distinct 
species ? Ep.] 
= An essential difference exists between the Flora of the sub-arctic and 
= that of the arctic region. The sub-arctie flora is characterized by the 
|. presence of forms which grace the plains of the temperate zone. Most 
of the genera are represented by only a single species; and many, 
whose focus is in more southern latitudes, extend their range close 
to the Arctic circle, though few venture beyond that limit. The prin- 
cipal are :—Ribes, Rosa, Lupinus, Aconitum, Sanguisorba, Thalictrum, 
Delphinium, Viola, Corydalis, Spiræa, Andromeda, Pyrola, Valeriana, 
— Solidago, Campanula, Galium, Pinguicula, Abies, Cistopteris, Nephro- 
_ dium, Marchantia, &c. The vegetation of the Arctic circle is chiefly 
. distinguished by the prevalence of alpine plants, the pride of mountains 
. of more genial climes. All are low and dwarf, many tufted, forming 
. dense masses. The most numerous natural orders are Saxifragee, 
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