FLORA OF SHELL HAMMOCKS AND CULTURAL FLORA. 133 



open vegetation of low perennials and herbaceous plants of various 

 families finds its home on the damp, often bare, ground, which is cov- 

 ered with a salty efilorescence. On such bare places the following are 

 found: 



Sabbatia steUaris. Tfesa marina. 



Gratiola hispida. Atriplex arenaria. 



Oldenlandia UUoralis. HeUotropiuTn curassavicurn. 



Monniera mormiera {Herpestln monniera) . Eleocharis capiiata. 



lAppia cuneifolia. Distichlis spicaia. 



Lijpjpia cuneifolia is a prostrate perennial, with rooting, creeping 

 stems. 



In the submerged salt marshes, with a firmer floor, formed Ijy 

 deposits of a heavier silt, large-stemmed and broad-leaved rushes and 

 grasses prevail, forming a compact halophile association of reeds, with 

 deeply submerged stout rhizomes tightly interlaced. The slender, 

 pale SjMrtina ^_>«^ew,§, with its stiff stems and erect involute leaves, 

 chiefly prevails with the tall Sch'jms 7'obustus and Spar'tinajjolystachya^ 

 and with Kosteletzkya virginica altheaefolia and Tpomoea f<agittata. 



Shell hammochs. — On the shore of the sea and of the larger inlets, 

 and along the banks of the bayou's narrow tortuous marine channels, 

 heaps of bivalve shells, frequently man}' ^^ards in length and from to 

 15 feet and over in height, are encountered, the accumulation of refuse 

 from the food supplv which served a race of men unknown to histor}^. 

 Large live oaks, aged magnolias, and pignut hickories cover these 

 heaps, along with dense copses of the red buckeye, the sea plum, and 

 the lime-loving Carolina buckthorn, the last two not known from any 

 other locality in the lower pine region. On these shell banks the 

 West Indian red cedar {Juniferus harbadenstH) is frequently found in 

 full perfection, the sturdy crunk spreading out its almost horizontal 

 branches, with their drooping branchlets, at from 12 to 18 feet above 

 the ground. This tree is frequently found on the low hammocks lining 

 the shores of the Gulf and its inlets from Mississippi to Florida and 

 along the Atlantic shore to Georgia. On the driest summits of the 

 shell heaps and on the sandy shores of the open sea, exposed to- wind 

 and tide, it is f requenth^ of low stunted growth with the trunk divided 

 from the base. Prickly pear in large patches frequently spreads 

 over the open places; Evolvulus alsinoides^ widely distributed in lit- 

 toral regions within the tropics of the New and Old World, has been 

 observed on the shell banks of Dauphine Island. Remarkable is the 

 never-failing occurrence on these shell banks from South Carolina to 

 Texas of Limnodea {Tkurberia) arkariscma in the scanty cover of herbs. 



CULTURAL PLANT FORMATIONS OF THE COAST PINE BELT. 



Of the 8,500 or 9,000 square miles covered by the rolling pine barrens 

 and pine flats of the coast plain east of the Escambia and Conecuh 

 rivers, not more than about 2 per cent is under tillage, and west of 



