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What peculiarity have the dry pasture species in common, and what those of 
moist woods? Have these peculiarities any such relation to the supply of 
moisture and light as we find to be the case among higher plants which grow 
under conditions correspondingly different? What enemies have lichens and 
how do they protect themselves against their attacks? Are there any special 
arrangements which facilitate the scattering of spores? How is moisture 
absorbed by the thallus? Is the moisture which is taken in at one part of the 
thallus conducted to other parts (or must each part absorb directly through 
its own surface)? How fast do the different organs of lichens grow? To 
what extent is the rate of growth affected by differences of moisture, light 
and temperature? To what age do different sorts of lichens attain? Other 
questions of a similar nature will readily suggest themselves to anyone inter- 
ested in these plants, and whereas many problems connected with the minute 
structure of lichens require considerable technical skill and the use of instru- 
ments of great delicacy, all that is needed for the profitable study of ques- 
tions of the sort above indicated, is intelligent observation and note-taking 
in the field, or the performance of simple experiments. 
A knowledge of the systematic relationship and the names of the species 
of one’s own locality at least is obviously a desirable preliminary to such 
work. The only manual of North American species is Prof. Tuckerman’g 
Synopsis. (A Synopsis of the North American Lichens: By Edward Tuck - 
erman, Part I, 1882. Published by S. E. Cassino, Boston, Mass. Part II, 
1888. Sold by Edwin Nelson, Amherst, Mass. Both parts now out of print). 
As this work was written for advanced lichenologists, beginners find it diffi- 
cult to use. The sources of these difficulties are mainly these: first, insuffi- 
cient acquaintance with the characters of the specimen studied, due to 
ignorance of just what to look for; second, not understanding the exact 
meaning of the phrases encountered in the book, or making the necessary 
allowances: third, the variability and close resemblance of the species them- 
selves. Let us consider how these difficulties may be overcome. 
The chief source of trouble is much increased by the too common habit 
among students of trying to read the descriptions and observe the characters 
of the species at the same time. Before referring to the book at all, one 
should make out as far as possible the characters of the specimen in hand. 
The following schedule of questions will, it is hoped, prove helpful by indi- 
cating the important features to be observed in such preliminary examina- 
tion. 
Schedule for Analysis. 
What is the locality and habitat? 
Is the thallus crustaceous, foliaceous (and appressed, frondose or um- 
bilicate), fruticulose or cladoniseform, or of a form intermediate? 
If crustaceous , is there a hypothalline fringe, and if so what color is 
it? Is the surface smooth, pulverulent, tartareous, verrucose, rimose, areo- 
late, or otherwise peculiar? Of what color is it in the younger and in the 
older portions? 
