August 14, 1903.] 



SCIENCE: 



2J5 



THE KENT COUNTY, MICH., UPL.VND PL.\NT 

 SOCIETIES. 



It was with much interest that I read Mr. 

 Liviugstoii's contributiou in the January, 

 1903, number of the Botanical Gazette upon 

 the ' Distribution of the upland plant societies 

 of Kent County, Mich.' I confess also to no 

 little disappointment. My home is in Kent 

 County, and several years of ecological study 

 there have yielded me results that do not in 

 all respects coincide with those contained in 

 the article under review. I have not seen the 

 author's more detailed account in the ' Ke- 

 port ' of the Michigan Geological Survey for 

 1901, and perhaps some things that here seem 

 obscure may there be made clear. In the first 

 place Mr. Livingston's results appear to be 

 based upon insufficient observation. The re- 

 gion chosen is too large, the flora too rich and 

 complex, to allow of a thorough study in a 

 single season. This manner of research, use- 

 ful as it is in securing valuable data, is 

 manifestly defective. Plant societies are not 

 so simple as they appear at first sight. Subtle 

 changes in soil,' exposure and water-supply 

 lead to corresponding changes in plant forma- 

 tions. A society in one region may appear 

 distinct, while in reality it is but one phase 

 of a larger society. Only a patient study of 

 years of a local flora throughout all the seasons 

 is of much worth, for only thus can a compre- 

 hensive and intelligent view of the prevalent 

 conditions of plant life, as well as the char- 

 acter and actual constituents of the flora, be 

 obtained. 



Mr. Livingston has five primary plant so- 

 cieties: (1) The beech-maple, (2) the maple- 

 elm-agrimony, (3) the oak-hickory, (4) the 

 oak-hazel and (5) the oak-pine-sassafras so- 

 cieties. These seem hardly natural. The 

 first two are very much nearer one another 

 than the following three, and the third and 

 fourth have a more intimate connection with 

 each other than either has with the fifth. 



Setting aside the strictly lowland societies, 

 the sylvan element of the Kent County flora 

 may well fall into four main tj-pes : 



I. The elm-soft maple society of the river 

 bottoms and other alluvial flats. Vlmus 



amcricana. Acer (la,sycarpuin and rubrum, 

 Juglans cinerea, Platanus occidentalis, Salix 

 nif/ra and various other trees are present. 

 Mr. Livingston has probably excluded much 

 of this element because of its hydrophytic 

 affinities, though his maple-elm-agrimony so- 

 ciety corresponds to it in part. We may call 

 this the bottoms-flora. 



II. The beech-maple-basswood society of 

 the timberlands. Acer saccharum and ni- 

 grum, Fagus ferruginea, Tilia Americana, 

 Fraxinus Americana and sambucifolia, Vlmus 

 Americana and several other trees are present. 

 It has an herbaceous flora strictly its own. 

 The soil is black and rich, and relatively 

 moist. This includes Mr. Livingston's first 

 and the greater part of his second society. 



III. The oak-hickory-sassafras society of 

 the oak-openings, having a great range of soils, 

 being found in swamps, rich plains and val- 

 leys, as well as baiTcn sands and clay hills. 

 Quercus hicolor and rubra clothe the margins 

 of swamps. Quercus macrocarpa and Muhl- 

 enbergii prefer the heavier clays, thus form- 

 ing the bur-oak openings. Quercus alba, ac- 

 companied by the various black oaks, prefers 

 the ordinary midland soils, though it is pres- 

 ent throughout the entire range of the genus. 

 Quercus coccinea, velutina and imbricaria 

 prefer the drier soils, and with them is rubra 

 (often) and stellata (rarely). The species of 

 hickory show a like preference of soil. The 

 flowering dogwood and the sassafras are also 

 quite peculiar to the oak openings. In re- 

 gions adjoining the timberlands the two floras 

 merge somewhat into one another, though the 

 oak flora is usually ascendant. In these for- 

 ests, known as timberland openings, a rich 

 fertile soil is present, perhaps the best of all 

 our soils for agricultural purposes. Oaks are 

 very rare in the true timberlands, but when 

 present are usually of colossal size. Only 

 Quercus rubra is at all frequent. Of hick- 

 ories only Carya amara is common in the 

 timberlands. Juglans nigra and Prunus sercr- 

 tina occur both in the timberlands and in the 

 oak openings, but are now scarce except as 

 shade trees in fields. 



IV. The pine-hemlock-canoe-birch society of 



