1907] CURRENT LITERATURE 225 
tiers of walled cells are organized, the uppermost being the “rosette,” the next 
developing the suspensor, the third forming the embryo, and the terminal one 
developing the ‘‘penetrating cap” characteristic of the genus. e embryo may 
reach the 16- or 32-celled stage before the suspensor begins to elongate. After the 
full development of the suspensor a series of long “embryonal tubes” arise from 
the proximal cells of the embryo. An interesting observation is the budding out 
of small secondary embryos from the main group of embryo cells, though ordi- 
narily but a single embryo is produced by the fertilized egg.—J. } 
Coastal plain of Georgia.—Concerning none of the older settled portions of 
the United States has there been so much difficulty in obtaining accurate informa- 
tion on plant distribution as for the extreme southeastern coastal plain. Because 
of its recent origin as a land area, its proximity to one of the most ancient land 
masses, and its connection with the tropics by way of the Florida peninsula, it 
forms one of the most critical regions on the continent for the investigation of 
plant origin, migration, and acclimatization. R.M. HARPER? has recently pub- 
lished the results of his investigations in southern Georgia and has made an 
important contribution to North American phytogeography. The classification 
of his observations, the clearness with which the results are presented, and the 
excellence of the illustrations add much to the value of the paper. 
The first part of the volume is devoted to a brief summary of the geological 
divisions of eastern North America and the subdivisions of the Georgia coastal 
plain. The Altamaha Grit forms a strongly marked physiographic region. It is 
probably Pliocene in age, occupies the middle third of the coastal plain of Georgia, 
and its topography is typically rolling. Rock outcrops are rare, the soil being 
formed mostly by the overlying LaF sini (sand and clay) and Columbia cane) 
formations. The vegetation is discussed under nineteen “‘habitat groups,” 
among which are rock outcrops, dry pine-barrens, moist pine-barrens, swamps, 
cypress ponds, sand hills, and hammocks. In each case the plant list is most 
carefully analyzed and shows at a glance the trees, shrubs, vascular and non- 
vascular herbs, their relative abundance, duration, flower color, and evergreen 
or deciduous habit. Each list is accompanied by a phenological diagram exhib- 
iting the times of flowering. The accompanying descriptions give the character- 
istics of the habitat, ecological notes, geographic ranges of the plants, and their 
taxonomic relationships. In the final summary the relations of the typical habi- 
‘tat groups to each other and to other regions are represented by diagrams; some 
exceptional habitats are described, the weeds are listed, and the effects of civili- 
zation discussed. 
The second part of the paper presents a history of botanical exploration in 
the region, an annotated catalogue of the species, a summary of the catalogue, 
and a list of the papers consulted.—E. N. TRANSEAU. 
23 HARPER, ROLAND M., A a sketch of the Altamaha Grit region 
of the coastal plain of Georgia. Annals N. Y. Acad. Sci. 177: 1-415. pls. I-28. 1906. 
