io6 



VALLISNERIACEAE. 



Vol. I. 



4. Philotria minor (Engelm.) Small. 

 Lesser Water- weed. Fig. 251. 



Udora verticillata (?) minor Engelm.; Casp. 



Jahrb. Wiss. Bot. i : 465, as synonym under 

 Anacharis Nuttallii. 1858. 



Philotria minor Small, Fl. SE. U. S. 47. 1903. 



Dioecious water-plant; stems filiform, l°-ll° 

 long. Leaves in 3's or 2's, linear, 2i"-4" long, 

 i" broad or less, acutish; staminate spathe 

 about 2I" long, ovoid, sessile; sepals and 

 petals oval, ¥'-%" long; anthers about i" 

 long; pistillate spathe about 5" long; hypan- 

 thium-tube f-2' long (rarely longer) ; petals 

 and sepals elliptic, 4"-i" long; stigmas slen- 

 der, longer than the sepals, deeply 2-cleft. 



In ponds, lakes and slow streams. Wisconsin 

 to Ohio, Kentucky, Kansas and Arkansas. 



2. VALLISNERIA L. 



Sp. PI. 1015. 1753. 



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

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

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

 or spiral scape, with a tubular, 2-cleft, l-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 numerous, 

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

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



A genus consisting of 2 species, the one of 

 wide distribution both in the Old World and the 

 New, the other confined to the Gulf States. 

 Type species : Vallisneria spiralis L. 



1. Vallisneria spiralis L. Tape-grass. 

 Eel-grass. Fig. 252. 



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, i°-6° long, 2"-c/' 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 flower upon a long thread-like scape, 

 the spathe i'-i' 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' -7' long. 



In quiet waters, New Brunswick and Nova 

 Scotia to North Carolina, west to South Dakota 

 and Indiana. The " Wild or Water Celery " of 

 Chesapeake Bay, and a favorite food of the can- 

 vas-back duck. Aug.-Sept. 



Family 9. HYDROCHARITACEAE Aschers. 

 Frog's-bit Family. 

 Aquatic or mud-inhabiting herbs, with broad or narrow leaves borne on a very 

 short stem. Flowers regular, monoecious or dioecious, arising from spathes of 

 distinct or united bracts. Perianth superior, 6-parted, the segments usually all 

 petaloid, the flower-tube adnate to the ovary in the pistillate flowers. Stamens 

 6-12, distinct or monodelphous. Ovary usually 6-9-celled. Styles 6-9. Ovules 

 numerous. Fruit somewhat fleshy, usually indehiscent. Seeds numerous. 



About 8 genera and 20 species, in temperate and tropical regions. Thalassia in Florida. 



