50 PLANT LIFE OF ALABAMA. 



The slender stems of these tall reeds and rushes sway to and fro 

 above the humbler grasses (Homalocenchrus, etc.), round rushes (.fun- 

 ens spp.), galingales (Cyperns spp.), sedges ( Carcx spp.), and bur reeds 

 (Sparganiuin sp.). These form the floor of the spongy soil, which 

 is frequently of fathomless depth and more or less submerged. The 

 monotony of the gramineous vegetation is often relieved by various 

 showy flowers, namely: 



Iris versicolor, Iris hexagona (blue flag) . Mesadenia ( Cacalia) luinroldta (raralia) . 



Hymenocattis rotata (spider lily) . Lythrum lineare (lythruni) . 



Sagittaria spp. (arrowhead) . Oicuta maculata (water hemlock) . 



Pontederia cordata (pickerel weed) . Slum latifolium (water parsnip) . 



Hibiscus moscheutos (swamp rose mallow). Rumex aUwsimus (swamp dock) . 

 Asclepias lanceolata (swamp milkweed) . 



To the same class of hydrophytes belong the paludial plants con- 

 fined to the salt marshes of the seashore and the outlying islands with 

 their rigid salt grasses (Distichlis spicata, Spartina, spp.), black rush 

 (Juncus r owner ianus), club-rush (Scirpus maritimus), and the species 

 of the dicotyledonous orders mentioned above. The plants of these 

 associations of halophytes are nearly all perennials with stout, fre- 

 quently deepty rooted, running rhizomes. This vegetation of the 

 swamps and salt marshes encroaches upon the water with the shoaling 

 of the rivers and the formation of muddy banks in the inlets of the sea 

 and on the open shore, and serves to break the force of the waves, and 

 'finally, by the close interlacing of the rootstocks, binds the loose soil 

 into a solid matting as a bulwark against the ceaseless destructive 

 action of the water and winds. 



The paludial arboreal vegetation of the more or less submerged soil 

 of the alluvial districts has already been spoken of, and the flora of 

 the tree-clad swamps fringing the pine-barren streams and of the open 

 pine-barren swamp will be fully discussed in treating of the several 

 regions in which they occur. 



ORGANOTOPIC FLORA. 



These plants differ from all others in finding their habitat upon 

 other living plants or their decomposed remains. 



EPIPHYTIC PLANT ASSOCIATIONS. 



The epiphytes are simple lodgers living upon trees in an atmosphere 

 saturated with moisture, without depending for their nourishment on 

 the tissues of the supporting plant. Only a few of the many species 

 of these plants which lodge in the trees of the Tropics are represented 

 in the flora of Alabama. They inhabit the trees of the damp or semi- 

 swampy forests of the Louisianian area. The Spanish moss (Tilland- 

 sia usneoides), a rootless plant of the Bromelia family, simulates in its 

 habit the lichen Usnea of the Northern forests. This plant draws 



