CHARACTERS OF LOUISIANIAN AREA. 95 
centrally located station where meteorological observations have been 
made during a series of years: 
1 Temperature (degrees F.). Mean pre- 
cipitation 
Maximum.| Minimum.| Mean. (inches). 
51 14,12 
64 16.10 
79.4 16.85 
74 11.33 
The heat during the warmest season is tempered by the Gulf breezes 
prevailing from forenoon to late in the afternoon. The vapor-laden 
currents from the Gulf in their unhindered sweep over the plain dis- 
charge their moisture quite evenly throughout the year. 
It has been shown that many of the plants frequent throughout the 
Carolinian area and types characteristic of the southern exposures of 
the Alleghany Mountains find their southern limit of vegetation on 
the hills bordering upon the coastal plain. A similar limitation has also 
been pointed out for a number of shrubs and trees, clearly marking 
the border line between the Upper and Lower Austral life zones. 
This zonal border, marked by trees strictly confined to the Louisianian 
area of the Lower Austral zone throughout its extent from east to west, 
not only in Alabama, but from the Atlantic coast to the eastern border 
of the Southwestern arid plains, deviates but slightly from the line of 
latitude 32° 30’, and is clearly indicated by the northwestern limit of 
the following species: 
Magnolia foetida (M. grandiflora L.) (mag- Quercus laurifolia (laurel oak). 
nolia) . Quercus lyrata (overcup oak). 
Hicoriamyristicueformis(nutmeghickory). Quercus catesbaet (turkey oak). 
Hicoria aquatica (bitter pecan). Pinus glabra (Southern spruce pine). 
The evergreens, consisting of pines on the light siliceous soils and 
of broad-leaved species in the mesophile forest, predominate largely 
over the deciduous forest growth, and the frequency of types identical 
with tropical forms, or closely allied to them, impress upon the vege- 
tation of this life area the character of the subtropical regions. 
The cultural plant formations of these regions, and confined within 
the limits of this zone, are: 
Gossypium herbaceum (cotton) . Sorghum halepense (false Guinea or John- 
Zea mays (Indian corn). son grass). 
Saccharum officinarum (tropical sugar Penicillaria spicata (cat-tail millet) . 
cane). Panicum barbinode (Para grass) . 
Oryza sativa (rice) . Chaetochloa italica (Italian millet) . 
Sorghum vulgare (Durrha, Kafir corn). 
The growing of the cereals of this list replaces almost exclusively 
the cultivation of small grain. 
