128 MICHIGAN ACADEMY OF SCIENCE. 



ramea. Hack. The iutioduced Russian thistle is fast taking the place of 

 the Atlantic sea kale. 



The flora of the pine and oak barrens is properly distinct from the 

 littoral flora mentioned. The scrub pine is very characteristic of it. The 

 sweet fern is omnipresent. Bearberry is frequent, while acres in the tree- 

 less regions are whitened with cudweeds and everlastings. The various 

 oaks try to grow, but fires have consumed the little original humus, and 

 often only poplars, willows, choke cherries, and sweet fern exist to warn 

 the settler of a burnt out soil. These regions are truly desolate. 



The mesophytic vegetation is of three chief sorts. 1. The clay banks of 

 Lake Michigan. The Philadelphia lily, painted cup, ivory sedge {Carex 

 eburnea, Boott.), balsam poplar, and a few golden rods and anemones 

 characterize it, though doubtless it belongs properly to the birch woods 

 flora. But the beach plants creep up the clay as the beach sands blow 

 along it, and give it a littoral aspect. 2. The flora of the pine and oak 

 forests. The better pine lands belong here. Originally the white pine. 

 Norway pine, and the hemlock were the chief trees, with some admixture of 

 birch and oak, but now the oak has supplanted quite completely the orig- 

 inal flora. It is the old millennial conflict of the gymnosperm and the angio- 

 sperm, in which the angiosperm is eternally the victor. Not only is the 

 weakness of its naked ovary the cause of the pine's rout, the reckless cut- 

 ting of the pine forests has given to the oak its opportunity to exterminate 

 its foe. But the pine is no mean antagonist. Left to itself it will hold its 

 own well. It, however, needs ages of preparation. Two things are 

 requisite to its growth besides proper climate and soil. 1. It needs air 

 and light. 2. Trees need to grow close together to keep out and shade out 

 the angiosperm. For the shade of a conifer is perpetual, and only a few 

 pale plants flourish beneath it. A deciduous forest allows the spring vege- 

 tation to blossom and fruit unhindered by excessive shade, Avhile the 

 evergreens never allow such a growth. The two conditions of the pine's 

 growth are paradoxical, and make it hard for a new pine to start. The 

 crest of a pine forest resembles a vast series of cone-shaped roofs. This 

 gives light to the top of the tree, and the terminal bud is relatively more 

 important to a conifer than it is to an oak. The branches below where the 

 various roofs join become feeble at first, then die away. If one tree is 

 too close to another, its inner branches perish, leaving only its top and 

 outer branches. If a tree dies, or the snow breaks a top so as to admit the 

 light to the ground, the proper conditions for a new pine exists, and the 

 little one is protected by the close society of the old, and still has room to 

 seek the sky. But the young grow only as they are needed, hence when 

 a forest is felled, but a few young plants are left, and the oak has a clear 

 field. Wherever, as on a hillside, a tree is left and a nucleus is formed,' 

 the pine will even thrust out the oak. It grows faster, it is on a soil 

 native- to it, consequently it shades out the intruder. It marshals its 

 young around it and together they form the nucleus of a forest. Un- 

 fortunately the places where the pine thus persists are rare. The frequent 

 fires harm the pine with its resinous wood more than it does the young 

 oak with its stout taproot. Tlie homlock is all but exterminated. Only 

 in two or three places around Manistee does it attempt to gain its lost 

 ground, then it stands in comi>act clusters, forming almost impenetrable 

 thickets with a shade darker than any I have seen elsewhere. Lumbermen 

 say that the hemlock will not stand isolation, that it dies as soon as it is 

 left alone. Certain it is that its chance of existence is more precarious 



