36 HARPER: PLANT POPULATION OF MICHIGAN 
are incorrect. Future explorations will doubtless necessitate 
changing the sequence of many of the species remote from the 
head of the list; but as it is, the present sequence corresponds very 
well with what one might obtain by counting the number of times 
each species is mentioned in previous descriptions of the vegetation 
of the same region. 
The species are first divided into large trees, small trees, vines 
and large shrubs, small shrubs, and herbs. Large trees are large 
enough to be sawn into lumber, small trees large enough for posts, 
large shrubs for canes or bean-poles, and so on down. Woody 
vines are combined with large shrubs, because otherwise in the 
absence of numbers there would be nothing to indicate how rela- 
tively scarce they are, but their names are italicized to distinguish 
them. Some small evergreen plants which have perennial stems 
above the ground, such as Eguisetum spp., Lycopodium, Chimaphila, 
Gaultheria, Epigaea, Chiogenes, Oxycoccus, Mitchella, and Linnaea 
( “chamaephyte” class of Raunkiaer, in part), are classed 
with the herbs on account of their small size and lack of true woody 
tissue. 
Evergreens are indicated by heavier type, as usual, and the 
names of weeds enclosed in parentheses, whether they are treated 
as exotics in the manuals or not.* The three commonest modes of 
dissemination are indicated by somewhat arbitrary but suggestive 
symbols, as follows: wind-borne seeds, Y; fleshy fruits, O; barbed 
fruits, X. It would have been interesting to indicate annuals, 
biennials, perennials, etc.} (or better still perhaps the Raunkiaerian 
growth-formst!}, as well as the blooming periods and color of flowers, 
but there are too many cases in which these data are not yet 
known accurately enough. The usual habitats of the different 
species are given in a few words. 
In each major group the species are arranged as nearly as 
possible in order of present abundance. Very likely a similar 
census taken fifty years ago would have placed Pinus Strobus at 
the head of the list, and arranged some of the other trees dif- 
ferently, and excluded some of the weeds entirely. On account of 
* See Bull. Torrey Club 35: 347-360. 1908; 37: II7-120. 1910. 
-T Asin Ann. N. Y. Acad. Sci. 17: 36-37. 10906, for example, 
t For an easily accessible reference to Raunkiaer’s system, and an illustration of 
_ use, see Taylor, Am. Jour. Bot. 2:32. 1915. 
