831 



So Humboldt, I think, observes that the damp shaded forests of the 

 Upper Amazons and Orinoco rivers, where frequent rains and a 

 clouded sky maintain a majestic arboreous vegetation, are far poorer 

 in the number of species they produce than the open burnt-up cam- 

 2?os of Brazil, covered with an infinite variety of low shrubby plants, 

 with a host of herbaceous ones scarcely less numerous. The 

 astonishing number of plants that crowd the arid shores of the Medi- 

 terranean, where the great hygrometric dryness forbids the growth of 

 the major part of our deciduous thin-leaved forest trees, and the land- 

 scape is scantily clothed with triste thickets of evergreen and cork 

 oaks (Quercus Ilex and Q. Suber), wild olives (Olea sylvestris), and 

 pines (Pinus pinea and P. halepensis), is perhaps not much inferior to 

 the amount of species on an equal area between the tropics, though 

 differing in kind, and owes its existence to the uninterrupted action 

 of solar radiation through the long dry summer of that inland basin. 

 Experience fully proves that a wet and consequently cloudy climate, 

 however mild and agreeable, sustains a flora distinguished usually by 

 great luxuriance, but by as remarkable a paucity of species, which, 

 however, make some amends for their fewness by their beauty or pe- 

 culiarity. New Zealand, Ireland and southern Patagonia furnish 

 striking illustrations of this fact, in the comparative poverty of their 

 ultra-oceanic but handsome and peculiar phanerogamic floras. Mr. 

 Watson found northern (British) forms constituting a large proportion 

 of the Azorian vegetation, in a climate warm enough to ripen the 

 orange, but too cloudy and humid for the great mass of Portuguese 

 and Spanish plants, requiring a larger share of direct solar light to 

 flourish spontaneously.* Enough has been said to show why so 



* The climate of this part of England along the south coast combines the advan- 

 tages of an insular and continental position. In summer we enjoy the warmth radi- 

 ated from the adjacent continent, and from the broad expanse of mainland to the 

 north of us, which ensures us considerable hygrometric dryness, and more sunshine 

 than falls to the lot of the northern counties, where the land narrows betwixt wider 

 waters, and losing the advantages of terrestrial radiation, becomes more completely 

 oceanic. In winter, on tbe other hand, our southerly position and the warm vapours 

 from the Channel generate a tolerably mild temperature, and the great prevalence of 

 south-westerly winds renders that season more rainy than frosty ; but except on and 

 near the coast, the mean heat of winter in Hants is little, if at all, higher than in the 

 north of England or Scotland, althougb tbat season is of shorter duration and pre- 

 ceded by a longer and drier autumn, and followed by an earlier, though often equally 

 cold spring, the east winds at that period blowing almost as constantly and keenly as 

 on any part of the coast west of the Foreland Point, and constituting here in the 

 months of March, April, and too often in May, the " blackthorn winter," our truest 



