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 (-/un- 
cus spp-), galingales (Cyperus spp.), sedges (Carex spp.), and bur reeds 
(Sparganium 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: : 
Tris versicolor, Iris hexagona (blue flag) . Mesadenia ( Cacatia) lanceolata (cacalia) . 
Hymenocallis rotata (spider lily). Lythrum lineare (lythrum) . 
Sagittaria spp. (arrowhead). Cicuta maculata (water hemlock). 
Pontederia cordata (pickerel weed). Sium latifolium (water parsnip). 
Hibiscus moscheutos (swamp rose mallow). Rumex altissimus (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 roemerianus), 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 deeply 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 ot 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 PLAN 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 (Zilland- 
sia usneoides), a rootless plant of the Bromelia family, simulates in its 
habit the lichen Usnea of the Northern forests. This plant draws 
