268 



THE FORMATION 



character will show in different parts of the world a vegetation taxonomically 

 very different. It may some day be possible to use a binomial or trinomial 

 for this purpose, somewhat after the fashion of taxonomy, in which the 

 habitat name will represent the generic idea as applied to formations, and 

 a term drawn from the floristic impress the specific idea. Such an attempt 

 would be futile or valueless at the present time; it could not possibly meet 

 with success until there is more uniformity in the concept of the formation, 

 and until there has been much accurate and thorough investigation of actual 

 formations, a task as yet barely begun. At present, it seems most feasible 

 as well as scientific to designate all format ion "^ nminving similar habitats 



Tig. 69. Aspen forest formation (PopuUts-hylium), the typical stage 

 of burn successions in the Rocky mountains ; it is sometimes an anom- 

 alous stage in primary successions, interpolated in place of the thicket 

 formation. 



by a name drawn from the character of the latter, such as a meadow forma- 

 tion, poiiim, a forest formation, hylium, a desert formation, crcmium, etc. 

 A particular formation is best designated by using the generic name of one 

 or two of its most inTportant species in conjunction with its habitat term, 

 as Spartina-Elyinus-poium, Ficea-Piniis-hylium, Ccrcus-Yucca-crcmium, etc. 

 Apparently a somewhat similar .nomenclature is adapted to successions. 

 The cause which produces a new habitat may well furnish the l)asis for 

 the name of the general groups of successions, as pyrium (literally, a place 



