448 THE CANADIAN NATURALIST. [Dec. 



century afterwards the estimate had increased five-fold. In 1847 

 it was announced as 92,920 ; and now, Meyers and others calcu- 

 late the entire vegetation of our planet to consist of some 200,000 

 species. The aborigines of New Zealand have learned to distin- 

 guish by name some 700 species of the trees and plants produced 

 on their own island, a number considerably greater than that 

 described by Theophrastus in the first history of plants ever given 

 to the world. But besides those plants which the pious and 

 philosophic Ray says " are by the wise disposition of Providence 

 proper and convenient for the meat and medicine of men and 

 animals" — besides those which enable the botanist, like his proto- 

 type in Milton's Comus, to 



" Ope' his leathern scrip 



And show simples of a thousand names, 



Telling their strange and vigorous faculties," 



we find vegetable life in its most simple form and develop- 

 ment represented by the mere primary cell ; and of the one- 

 celled plants the most interesting order is the Diatomaceae. The 

 yellow- dust, which falls like rain on the Atlantic, near the Cape- 

 de- Verde Islands, and occasionally drifts even to Italy and 

 Central Europe, was found by Ehrenberg -to consist of myriads 

 of silicious-shelled microscopic plants. Darwin discovered that 

 a cloud of dust, drifting through the air from America to Af- 

 rica, and coming in contact with the rigging of the ship in 

 which he was sailing, consisted of the shelly coverings of 

 diatoms. The naturalists of the Antarctic Expedition constantly 

 found them adhering to the lead, after sounding depths in the 

 ocean which would have engulphed the loftiest peaks of the Andes. 

 Humboldt, on the other hand, has shown that they float in the 

 upper currents of the atmosphere perhaps for years, until brought 

 down to the earth by vertical currents. But, turning from these 

 — and the almost equally interesting family of the Fungi, which 

 are so destructive to our bread, fruits, and other objects of 

 domestic economy, — I would now, on the Solomonian principle of 

 ascending from the hyssop to the cedar, say a few words respect- 

 ing some of the giants of vegetation. I take, as an illustration, 

 the celebrated big-trees of California. This group of huge 

 conifers (placed botanically between the pine and the juniper) 

 was discovered in 1850, by some hunters when pushing their 

 way through a hitherto unexplored forest in the Calaveras country, 

 about 240 miles from San Francisco. It is deeply to be re- 



