294 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
resort to the collection of plants in the various herbariums and to the 
lists of plants published in various books and journals; in this way 
the distribution of the plants is discovered, the knowledge of which 
is valuable both to the taxonomist and the biologist. In this method 
the research worker must either for himself consult all the plants im 
the herbariums and represented in the lists and must verify ther 
identification or else depend for their value upon the person identify- 
ing the plant or publishing its name. It is not necessary to see the 
plant growing. The species are all units and are well represented as 
such by mere names. 
of vegetation the plant in question belongs. -. 
So far it may be seen that one can by research among collections ‘ 
and lists of plants obtain both a fair idea of the species of plants from 
any particular region and some knowledge of the type oF LYP® The | 
vegetation found in that region. So much can be done at home. ~~ 
types, however, represent groups, and as the groups are often com” 
posed of many species which have one feature in common but often : 
have a wide range in size, outline, method of branching, and cole 
it is impossible to give a complete and at all real picture of a locality 
without considering these various features, characteristics which can : 
be ascertained only by traveling among the regions in question ©” 
by viewing personally the types of groups or composites of ene : 
as they are growing together in the various localities. The modifica- e 
tions of groups are so great that it is necessary to visit many locau"®” — 
and to visit the same localities at various times of the year before on€ | 
can obtain a true knowledge of the character of the vegetation. 
