4 
North Carolina Experiment Station 
Climatic Climax. Tlie climax vegetation on areas characterized 
by favorable physiographic conditions with regard to plant growth. 
Physiographic Climax. The climax vegetation on areas the sur¬ 
face conditions of which are permanently unfavorable to the climatic 
climax vegetation of the region. Most physiographic climaxes are 
edaphic climaxes i. e., the soil content is the significant entity in the 
determination of the vegetation. 
Subclimax. A specific formation or association which is changing 
very slowly due to the relative stability of its habitat. This stability, 
however, does not possess the permanence which characterizes the cli¬ 
max habitats of geological time periods. 
In the use of names of dominants for the formation names, it is not 
to he implied that these plants are present in all associations of the 
formation or in equivalent formations in other parts of the world. As 
types they illustrate the physiognomy of the formations. 
The undesirability of using plant names for the major groups is 
recognized, yet in the present state of ecological progress, it is probably 
best. Students in the future may easily make the necessary correla¬ 
tion by pointing out the ecological synonomy existing between the dif¬ 
ferent communities. 
In the organization which follows, no account has been taken of the 
minor plant formations such as those of the lichen and moss. With 
regard to the communities treated, only the formations and their 
principal associations are outlined in this paper. 
With regard to nomenclature, Small’s “Flora of the Southeastern 
United States” has been followed. 
FORMATIONS 
1. Uniola-Cakile formation 
2. Juncus-Spartina formation 
3. Typha Scirpus formation 
4. Potomogeton-Nymphcea forma¬ 
tion 
5. Ilex-Myrica formation 
6. Campulosus-Sarracenia forma¬ 
tion 
7. Nyssa-Taxodium formation 
8. Quercus-Aristida formation 
9. Syntherisma-Erigeron-Andro- 
pogon formation 
10. Quercus-Acer-Pinus formation 
11. Abies-Picea formation 
1. Uniola-Cakile Formation (Uniola paniculata, Cakile spp.) Dunes. 
Distribution. On seaside dunes and along sandy shores of sounds 
and rivers near the sea. Its best development is on the southeastward 
facing coast south of Cape Hatteras. Long stretches of the northeast¬ 
ward facing coast north of Hatteras are not characterized by the line 
of low T dunes which form the typical habitat of the Uniola grass. 
Habitat. The well-drained, humus-free soil of the dunes plus the 
omnipresent wind of this coastal locality make this habitat a xerophytic 
one, despite the condition of abundant rainfall. 
