THE CLIMAX AS A BASIS. 181 



Picea alba, P. mariana, and Abies balsamea is obviously related to the alpine 

 forest of Picea engelmannii and Abies ladocarpa. The lacustrian forest of 

 Pinus strobus, Picea rubra, Tsuga canadensis, and Thuja ocddentalis is just as 

 clearly related to the Pacific forest of Pinus monticola, Picea sitchensis, Tsuga 

 heterophyUa, and Thuja plicata. Both eastern and western forests have 

 an interesting correspondence in the case of important consocies also, such as 

 Larix americana and Pinv^ banksiana in the east and Larix ocddentalis and 

 Pinus murrayana in the west. If these North American forests are compared 

 with those of boreal Eurasia, a somewhat similar correspondence is seen. 

 The boreal coniferous forests of both consist of Picea, Abies, Pinus, and Larix; 

 the deciduous forests of Acer, Fagus, Tilia, Quercus, Fraxinu,s, Ulmu^, etc. It 

 is well known that a genetic relationship exists between the forests of north- 

 eastern North America and Europe, and that there is even a closer genetic 

 connection between the northern forests of our own continent. All of the 

 evidence in our possession from the standpoint of development, floristic, and 

 climate, indicates that the boreal forests of the two continents are distinct 

 though related formations, and that this is also true of the deciduous forests. 

 A comparison of the development, population, and habitat of the five northern 

 coniferous forests of North America — ^the boreal, lacustrian, montane, alpine, 

 and Pacific, indicates that they constitute five distinct climaxes, though their 

 genetic relationship is close. As already stated, however, such a conclusion 

 is tentative and suggestive, and not at all to be regarded as final until the phylo- 

 genetic study of climaxes has tested the evidence. 



Names of climaxes- — Since each climax is a formation in the developmental 

 sense proposed in the present work, it is designated by the use of terms ending 

 in -ion. Because of the small number of climax areas as compared with 

 developmental ones, only a few formational names are needed. The number 

 of names is further limited by the impossibility of drawing exact lines on the 

 basis of water relations at present. Hence, the existing need is perhaps suffi- 

 ciently met by the following list: forest, hylion; scrub, dryon; desert scrub, 

 eremion; saline scrub, halion; swamp scrub, helion; heath, oxyon; grassland, 

 poion; tundra, crymion. It has already been stated that heath, prairie, etc., 

 are often or regularly subclimaxes, in which case they would take the suflix -is, 

 which is used to denote the associes. The terms dryon and oxycm are merely 

 shortened from forms proposed earlier (Clements, 1904, 1905). 



The designation of a particular climax by means of two of the most impor- 

 tant consociations seems superior to any other method for the present. For 

 North America it is brief, definite and characteristic in every case but that of 

 the Picea-Abies-hylion, which may apply either to the boreal or the alpine 

 forest. It is suggested that the latter be distinguished on its general regional 

 character as an alpine forest, by the designation orohylion. The use of the 

 genitive of the specific names makes the term unwieldy, though otherwise 

 preferable. In formations with a single outstanding consociation, such as the 

 Bowtelouetum of the Bouteloua-Bulbilis-poion, it is really necessary to use but 

 one generic name, viz, BovMoua-poion. The distinction of Old and New 

 World formations with the same dominant genera is a more difficult task. 

 Perhaps it may best be done by using the species which on the whole seems 

 most important, e. g., Picea abietis hylion, Picea canadensis hylion, Picea 

 engelmannii hylion. In the case of frequent use in the same context it will 



