558 
understood as one of the series of successions leading to the Deciduous 
Forest Climax. When the Prairie Formation is succeeded by Deciduous 
Forest associations, it is exactly the same phenomenon that occurs when 
the Deciduous Forest invades and succeeds the Northern Evergreen For- 
est Climax—the Abies-Picea-Betula Association. Only in this sense is the 
Andropogon furcatus Association a temporary climax. 
We must therefore conclude that the Andropogon furcatus Asso- 
ciation is the climax association of the true prairies. 
Where the prairie grades off almost imperceptibly into Plains vege- 
tation there is an intermediate region in which it is too dry for Andro- 
pogon furcatus and in which the Andropogon scoparius association is 
the climax association of the prairie. In this intermediate region in the 
hydrarch succession, Andropogon furcatis is succeeded by AniGECs 
Scoparius. 
ANNOTATED List OF SPECIES 
No attempt was made to make a complete list of all the prairie 
species in the state. The following list is added primarily to give a 
more complete record of the secondary species of the different asso- 
ciations, and an attempt is made to check them with reference to the 
associations in which they are most usually found. Introduced species, 
ruderals, and species found only on railway rights-of-way or greatly 
disturbed areas are listed usually without reference to associations. 
Some of the weeds and most of the species characteristic : of forest bor- 
ders and small forest openings, which do not extend very far out on the 
prairie, are omitted. This list, compiled from small relic areas and un- 
der the present disturbed conditions, is subject to the limitations pre- 
viously discussed and can only approximate the distribution under natural 
conditions. Consequently reference is made only to the more promi- 
nent associations. These associations are referred to in the tabulation 
by initial letters as follows: S. f. a., Scirpus Auviatilis association, C. a., 
Carex association, S. M. a., Spartina Michauxiana association, C. c. a., 
Calamagrostis canadensis association, P. v. a., Panicum virgatum asso- 
ciation, A. f. a., Andropogon furcatus association, A. s. a., Andropogon 
scoparius association, M. g. a., Mixed grass association on sand, P. 
b-g. a., Pioneer bunch- -grass association on sand, P. p. a., Panicum pseu- 
dopubescens association. The nomenclature follows the Vienna Code, 
as given in the seventh edition of Gray’s Manual. 
