BOTANY. 349 



fermented liquors under the form of yeast. This consists of more or less 

 oval bodies, which continually give off joints so as to produce short, 

 branched, necklace-like threads. These joints fall off, and rapidly give 

 rise to a new generation, which is successively propagated till the substance 

 is produced which is known under the name of yeast. Placed under proper 

 conditions, the joints undergo a further change, and give rise to two or 

 three species of mould. 



We have put together these curious facts, believing that they will be novel 

 and interesting to many who have little suspected how much of destructive- 

 ness, of use, of ornament, and of nutriment lie hidden in this humble order 

 of plants. But we may properly ask, What is their office and service in 

 the grand economy of creation ? Such office they have, and such service 

 they perform, though cast out and trodden under foot of men. " If the tree 

 fall toward the south, or toward the north, in the place where the tree falleth, 

 there it shall be." So saith the Preacher; and the fungologist adds to his 

 discourse what he has observed by studying the fallen tree. Of itself, it 

 would long cumber the ground, and lie all its length a useless log. But the 

 invisible spawn of the fungus draws nutriment out of its dead mass, and 

 begins to grow upon this ligneous tomb, and to thrive upon the decay which 

 it hastens and aggravates. It is life, even though of the lowest order, spring- 

 ing out of death. It is birth and increase coming up from the very mass of 

 decay and diminution. The tree rots into powder, the fungus flourishes and 

 spreads out until it forms a new soil. Floating and flying seeds drop down 

 from the wings of the wind and find a lodgment here, and begin to sprout 

 and bring forth leaves. Companions are added to them from every passing 

 breeze; and, finally, where once the dead tree lay prostrate, a vegetable 

 blank in the midst of green life all around it, up come herbs and plants, and 

 the kindly earth is rid of one great, useless burden, and ready to bear again 

 the leaf and stem, and perhaps the flower and fruit. 



AMERICAN FOSSIL FLORAS. 



At the meeting of the American Association, 1860, Dr. Newljerry gave a 

 sketch of the succession of different floras on the North American continent, 

 remarking that the Devonian and Carboniferous floras had been carefully 

 studied and characterized by the prevalence of cryptogamous plants, as ferns, 

 etc., and that the floras of America during these ages were strikingly like 

 those of Europe of the same epoch. The Permian flora was scarcely known 

 in this country; it was but a continuation of the Carboniferous. He observed 

 that the Triassic and Jurassic floras were characterized by the prevalence of 

 numerous and beautiful Cycadaceous plants which had been studied and 

 beautifully illustrated by European fossil botanists, but had hitherto been 

 very little known in this country. Recently he had procured a large number 

 of fossil plants of this age from Xcw Mexico and elsewhere, which had 

 shown that, as in Europe, the flora of America, during the period of deposi- 

 tion of the New Red Sandstone, was cycadaceous in character and similar to 

 that of Europe. At the commencement of the cretaceous era, however, the 

 flora of the continent was revolutionized, and apparently suddenly, though 

 doubtless gradually. The broad-leaved dicotyledonous plants were intro- 

 duced, and the vegetation of the continent assumed the general aspect which 

 it has at the present day. Among the cretaceous plants are found species of 

 Liriodendron (tulip-iree), Liquid-amber (swce'-gum), Sass<iJ'r;is, etc., etc., gen- 



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