ALTAMAHA GRIT REGION OF GEORGIA 



43 



most habitat-groups in temperate climates. There are two vines, 

 both woody. Most of the trees and shrubs are evergreen and 

 most of the herbs are not. The herbs are mostly perennial. 

 The trees all have anemophilous flowers, while nearly all the 

 shrubs and herbs are entomophilous. Yellow flowers are most 

 numerous, with white and purple next. The phaenological dia- 

 gram shows that there are about a dozen species in bloom at 

 the same time late in May and early in September, but only about 

 half as many at the end of July. This scarcity of summer 



Jan. Feb. Mar. April May June July Aug. Sept. Oct. Nov. Dec. 



10 



1 i. . — ^TIW^--,.--:-^^ 1- ^r^t-^^--! f 1 



10 



Fig. 2. 

 Phrenological diagram for 40 plants growing on Altamaha Grit outcrops. 



flowers is characteristic of many other exposed rocky places, 1 

 and is due of course to the drying up of the rocks in the summer 

 sun. But this is not so marked in the Altamaha Grit region as 

 elsewhere, because there the extra rainfall in summer tends to 

 counteract the evaporation. 



The 40 species of flowering plants represent at least 26 fam- 

 ilies and 38 genera, pretty well scattered through the whole range 

 of families. But the most striking feature of the whole group is 

 the heterogeneity of their ranges. Two species, Marshallia 

 ramosa and Pentstemon dissectus, are not definitely known out- 

 side of the region, though they are not exclusively confined to 

 rock outcrops. Azalea Candida I have seen only on or near out- 

 crops of the Grit, but it has been collected by others at two or 

 three stations south of our territory. The remarkably anomalous 

 range of Chondrophora virgata has been discussed elsewhere. 2 

 A considerable number, including Senecio tomentosus, Ilysanthes 

 refracta, Crotonopsis , Manfreda, Arenaria, 5 Talinum, and some 

 of the bryophytes, are more at home on granite outcrops in 



1 See Small, Bull. Torrey Club, 24: 333. 1896; Mohr. Contr. U. S. Nat, 

 Herb. 6:67, 68, 82. 1901; Gattinger, Fl. Tenn. (ed. 2) 22, 23. 1901. 



2 Bull. Torrey Club, 32: 168. 1905. 



3 See Torreya, 4: 138-141. 1904. 



