TAPE-GRASS FAMILY. 



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i. PHILOTRIA Raf. Am. Month. Mag. a: 175. 1818. 



[EI.ODEA Michx. Fl. Bor. Am. i: 20. 1803. Not Elodts Adans. 1763.] 



[UDORA Nutt. Gen. a : 242. 1818.] 

 Stems submerged, elnogated, branching, leafy. Leaves opposite or whorled, crowded, 

 i-nerved, pellucid, minutely serrulate or entire. Flowers dioecious or polygamous, arising 

 from an ovoid or tubular 2-cleft spathe. Perianth 6-partcd, at least the 3 inner segments pet*- 

 loid. Staminate flowers with 9 stamens, the anthers oblong, erect. Ovary Kelled with 3 

 parietal placentae. Stigmas 3, nearly sessile, 2-lobed. Fruit oblong, coriaceous few-seeded. 

 [Name from the Greek, referring to the leaves, which are often whorled in threes.] 



About 8 species, inhabitants of fresh water ponds and streams in temperate and tropical America. 



i. Philotria Canadensis (Michx.) Britton. Water-weed. Ditch-moa*. 



Water Thyme, i Fig. 207. ) 



Elodea Canadensis Michx. Fl. Bor. Am i : 30. 1803. 



Anacharis Canadensis Planch. Am. Ill o 



75- 1849. 



Philotria Canadensis Britton, Science vll. ) 2 : 5. . 1895. 



Stems 4'-3 long, according to the depth of water. 

 Leaves linear or elliptic, acute or obtuse, serrulate or 

 entire, verticillate in 3*3 or 4's or the lower opposite, 

 i"--]" long, #"-2" wide ; flowers axillary, white, the 

 staminate minute, sessile, breaking off at the time of 

 flowering and rising to the surface where they shed 

 their pollen around the pistillate ones ; pistillate 

 flowers expanding on the surface of the water which 

 they reach by means of the slender calyx-tube which 

 varies in length from 2'-i, their spathes s"~7" long; 

 stigmas spreading, papillose or pubescent. 



Nearly throughout North America, except the extreme 

 north. Naturalized in Kuropt-. It has been maintained 

 that there are four North American species. Majr-Attff . 



2. VALLISNERIA L. Sp. PI. 1015. 1753. 



Aquatic dioecious submerged perennials, with long grass-like floating leaves. Stam- 

 inate flowers with a 2-3-parted spathe on a short scape, numerous, nearly sessile on a conic 

 receptacle ; perianth 3-parted ; stamens generally 2 (1-3). Pistillate flowers on a very long 

 flexuous or spiral scape, with a tubular, 2-cleft, i-flowered spathe ; perianth-tube adnate to 

 the ovary, 3-lobed and with 3 small petals ; ovary i-celled with 3 parietal placentae ; stigmas 

 3, nearly sessile, short, broad, 2-toothed with a minute process just below each sinus ; ovules 

 unmerous, borne all over the ovary-wall, orthotropous. Fruit elongated, cylindric, crowned 

 with the perianth. [Named for Antonio Vallisneri, 1661-1730, Italian naturalist.] 



A tnonotypic genus of wide distribution both 

 in the Old World and the New. 



i. Vallisneria spiralis L. Tape- 

 grass. Eel-grass. (Fig. 208.) 



Vallisneria spiralis L. Sp. PI. 1015. 1753. 



Plant rooting in the mud or sand, stolon- 

 iferous. Leaves thin, narrowly linear, 5- 

 nerved, obtuse, sometimes serrate near the 

 apex, }4-6 long, 2 // -o/ / wide, the 2 marginal 

 nerves faint; the staminate bud separates from 

 the scape at the time of flowering and ex- 

 pands upon the surface of the water ; pistil- 

 late flowers upon a long thread-like scape, 

 the spathe l / 2 '-\' long, enclosing a single 

 white flower ; ovary as long as the spathe ; 

 after receiving the pollen from the staminate 

 flowers the scape of the pistillate contracts 

 spirally ; ripe fruit 2'--' long. 



In quiet waters, New Brunswick to Florida, 

 west to Minnesota, Iowa and Texas. The " wild 

 celery" of Chesapeake Bay, and a favorite food 

 of the canvas-back duck. Aug. -Sept. 



