

152 



BOTANICAL GAZETTE 



[FEBRUARY 



(7) plants of wet meadows or moist forest; (8) marsh plants; (9) plants 

 partly submersed; (10) plants growing in water. 



In using the index most plants will be grouped around 4, 6, 8, and 10. 

 This will be the case especially with students who have had little experi- 

 ence in field work. Later, when a finer discrimination is developed, the 

 intermediate numbers will be employed more often. If extreme nicety 

 is desired, decimals may be used. They will be satisfactory in the study 

 of some particular community, as a meadow or a prairie, in which the 

 student becomes acquainted with relative moisture requirements of a 

 number of species. If less accuracy is required, plus and minus signs 

 furnish a useful means of distinction. Thus, the elms may be called 

 no. 6, the red maple 6+, and the red oak 6 — . Students in desert and 

 arid regions will need to work out the meanings of the index figures 2 

 and 3. Others will probably be content with calling all xerophytes 

 no. 4. A plant that occurs in a number of different habitats may be 

 indicated by two or more numbers, as, for example, Achillaea lanulosa 



There is no deep philosophical conception underlying the use of the 

 scale and no instrumentation is intended in connection with it. It 

 merely emphasizes the importance of water in the substratum and 

 furnishes a suitable terminology for description and a vocabulary for 

 thinking about soil moisture relations. It is possible that in research 

 work on floristics the use of this or some other suitable scale may be 

 found desirable. Perhaps workers in different localities might agree on 

 typical plants to represent the different index numbers. The scale may 

 well be used for a better understanding of transition areas, such as 

 occur between meadow and marsh or between meadow and dry grass- 

 land. Any piece of vegetation may be given an index number if the 

 indexes of its component species (previously determined in other situa- 

 tions) be averaged. Thus one might recognize a no. 6 meadow, a 



no. 6.5 meadow, or a no. 7 meadow. 

 Colorado, Boulder, Colorado. 



Ramaley, University of 



