FRESH-WATER MARSH VEGETATION. 437 



cordata) almost always grow with the Typha. Bulrush (Scirpus 

 lacustris), wild rice {Zizania aquatica), usually small and 1 meter or 

 so (3 or 4 feet), but sometimes 2i meters (8 feet) high, Sium cicutae- 

 folium, and Polygonum hydropiperoides are ordinarily abundant ele- 

 ments in this assemblage. At some points great quantities of Acorus 

 calamus, in nearly pure association, occupy that zone of the marsh 

 which immediately borders the open water. In limited areas Juncus 

 effusus is predominant in the growth that fringes open water. In 

 others Dianthera americana prevails, and is sometimes infested with 

 masses of the golden-yellow stems of Cuscuta gronovii. 



Farther from the channel, where the ground is a few centimeters 

 higher and the depth of the surface water is less, a greater variety of 

 species occur, many of which are characterized by showy flowers. 

 Indeed, there is no plant association of the region that is more note- 

 worthy in this respect, as the absence or scarcity of woody plants per- 

 mits a better display of the bright colors than is elsewhere possible. 

 Here, as in the outer belt, monocotyledons of grass-like habit are tin; 

 dominant form. Scirpus cyperinus criopliorum is often abundant. 

 The saw grass (C Indium effusuvi), so characteristic of the great 

 marshes in southern Florida, is sometimes the principal element of 

 the middle belt, especially along the Pasquotank River, near Eliza- 

 beth City. It does not grow as large as it does farther south, 1 to 1| 

 meters (4 or 5 feet) being the common height. Juncus canadensis, 

 J. effusus, and other rushes are common. Species of Rynchospora 

 (inexpansa, glomerata), of Kleocharis, and of Carex, notably C. striata 

 (forming strong tussocks), and, usually in rather shady places, C. 

 gynandra contribute largely to the plant, covering. The handsome 

 lilac-colored blossoms of Iris caroliniana are conspicuous in spring, 

 and the brilliant orange- red flowers of Asdepms ianceolata (pauper- 

 rulo) are even more so in midsummer. Erianthus saccharoides is 

 usually not abundant in the river marshes, but always attracts the 

 eye when present. The white, button-shaped heads of Eriocaulon 

 decangulare and the beautiful, fragrant,, rose-pink blossoms of Sab- 

 batia dodecandra are often characteristic features of this association. 

 In autumn the yellow rays of Bide us trichosperma give a bright color 

 to the whole marsh. Trisetum palustre and Saururus cernuus prefer 

 the shadier edges of the open marsh. Cicuta maculata attains a great 

 size in such situations, one plant having been observed which was 2\ 

 meters (8 feet) high, and 3 centimeters (over an inch) in diameter at 

 base. The snffruticous Decodon verticillatus, with numerous clusters 

 of showy purple flowers, is often abundant on the inner edge of the 



marsh. 



Numerous smaller and less showy plants enter into this association— 

 Centella asiatica, Hydroctyle umbellata, Proserpinaca pectinata, etc. 



Edges of Hygrophile Forest— Scirpus- Erianthus Association.— 

 Extensive tracts of wet land formerly covered with forest, but now 

 almost destitute of living trees, border the Dismal Swamp, especially 



