FLORA OF MICHIGAN. 15 



The following general notes on Climate and Distribution are from the 

 preface to the first edition by E. F. Smith: 



"The influence of climate on vegetation may be summed up in a few 

 words. The climate of the Lower Peninsula is not as severe as that of the 

 Upper, nor so even, but is subject to frequent, sudden, and extreme changes 

 of temperature as great a variation during the winter season as 53 Fahr. 

 in less than 24 hours having been recorded. Such rapid changes more or 

 less affect vegetation, especially the tender branches of cultivated trees, 

 which are sometimes seriously injured. In one or two instances a like 

 effect on our forest trees has been noticed. The annual range of temper- 

 ature is about 116, and the annual mean 46. Of rainfall, including 

 what falls in form of snow, we have, yearly, about thirty inches. Our 

 snowfall is much less, for the same latitude, than that of New York and 

 New England. In the center of the peninsula, we seldom have more than 

 a few inches at a time. 



"The proximity of the Great Lakes exerts a marked influence in 

 equalizing the temperature and the effects are marked upon our flora. 



"Trees like Liriodendron Tulipifera, Asimina triloba, Cercis Canaden- 

 sis, Gleditschia friacanthos, Cornus florida, Nyssa multi flora, and Morus 

 rubra, which belong to Ohio and Central Illinois, have crept northward, 

 favored by the mild influence of the lake winds, through the central and 

 western part of the Lower Peninsula, often beyond the middle, and the 

 same is true of smaller and less noticeable plants. 



"As might be expected from the uniform surface of the peninsula, the 

 flora is much alike throughout. Probably three-fourths of our species are 

 common to all sections, though by no means equally distributed; some 

 being very abundant in one district and rare in another at no great dis- 

 tance. In most cases such change is due to soil rather than to difference 

 in elevation, temperature, or atmospheric moisture. 



"The Lower Peninsula is covered with a deep drift of alternating sands, 

 clays, and gravels, and the flora of any section depends chiefly on which 

 of these happens to lie uppermost. With reference to its flora, the penin- 

 sula may be roughly divided into two great divisions the hardwood and 

 the softwood lands; one representing the Appalachian flora, and the 

 other, the Canadian. 



"The hardwood country lies south of latitude 43, and consists of very 

 fertile sand, clay, or loam, mostly cleared of the original forest, and largely 

 cultivated. 



" The sandy or stony drift of many river valleys in this section supports 

 a heavy growth of oak, frequently interspersed with walnut and hickory, 

 while the margins of the streams, and the neighboring swamps, abound in 

 soft maples, swamp and chestnut oak, white and black ash, elm, hackberry, 

 sycamore, butternut, and similar trees. Willows, dogwoods, viburnums, 

 and buttonbush, are common shrubs in the swamps; and hazel, hawthorn, 

 wild cherry and plum, June berry, witch-hazel, etc., are abundant on the 

 dryer ground. 



" On the uplands, and away from streams, clay, loam, and a peculiar 

 black muck soil supersede the sands and gravels of the valleys. The pre- 

 vailing timber here is beech and maple and oak forest in about equal pro- 

 portions. Beech and maple generally grow together, forming magnificent 

 forests of great extent. The best wheat farms are usually found on 

 uplands near streams, where the oak timber gradually shades into beech 

 and maple. Plains of fertile sand covered with a low, or scattering growth 



