302 ENDOGENOUS PLANTS 



angular at base, the sides flat ; stigma conical, oblique, about half 



as long as the style. 



AMERICAN SPARGANIUM. Bur-reed. 



Stem 9 to 18 inches high, flexuose, terete, sometimes with 2 or 3 short axillary 

 branches at summit. Leaves 6 to 24 inches long (mostly overtopping the stem), 

 and % to J^ an inch wide. Staminate heads 4 or 5 to 9, somewhat contiguous in 

 twos or threes. Pistillate heads 2 to 5 (usually 3), yellowish green, % an inch to % 

 in diameter, the lowest one often pedunculate. 

 Hdb. Sluggish rivulets ; ditches, &c.: frequent. Fl. July. Fr. Sept. 



Obs. This appears to be very nearly allied to simplex, of Eu- 

 rope. I have specimens from Wynn's Meadows, near the head 

 waters of the Brandywine, which are every way so much smaller, 

 that they might constitute if not a species-^&i least a variety, pumi- 

 lum. 



ORDER GIL NAIADA^CEAE. 



Immersed aquatics ; stems nodosely jointed, often radicating ; leaves cellular, with 

 sheathing stipules, or bases ; flowers mono-dioicous, axillary, naked and inconspicu- 

 ous, or perfect, and with a calyx, in pedunculate spadix-like spikes; ovaries 

 solitary, or 2 to 4 contiguous, yet distinct, 1 celled, 1-ovuled; seed without 

 albumen. 



$1. Flowers mono-dioicous, axillary, naked, monandrous. 



409. tfArAS, L. 



[Gr. Naias, a Water-nymph ; from its place of growth.] 



STAM. FL. a single stamen, inclosed in a membranous spathe; anther 

 at first subsessile, the filament finally elongated. PISTILLATE FL. 

 a single ovary, tapering into a short style : stigmas 2 to 4, subulate ; 

 ovule erect. Fruit a seed-like nutlet, inclosed in a loose epicarp. 

 Annuals.'' stems slender, dichotomously branching; leaves opposite 

 and verticillate ; flowers sessile. 



1. 1V flexilis, Rostkow. Leaves mostly verticillate in six,es, lin- 

 ear, membranaceous, denticulate near the apex. 

 Caulinia flexilis. Willd. $ FL Cestr. ed. 2. p. 519. 

 FLEXIBLE NAIAS. 



Stem 6 to 12 or 18 inches long, filiform, jointed, smooth. Leaves half an inch to 

 an inch long, aggregated or Bubverticillate in fours or sixes, sometimes opposite, 

 very narrow, dilated and sheathing at base. Seed oblong, shining, pale straw- 

 color. 

 .Hod. Ponds, and sluggish streams : frequent. Fl. July. Fr. Sept. 



41O. ZAffUTICHEI/MA, Micheli. 



[Dedicated to John Jerome Zannichelli; a Venetian Botanist.] 

 Flowers sessile, usually both kinds in the same axil. STAM. FL; a 

 single stamen, with a slender filament bearing a 2- to 4-celled anther, 

 PISTILLATE FL. usually of 4 sessile pistils in the same cup-shaped 

 involucre ; stigma somewhat peltate, often 2-lobed. Fruit an oblong 

 coriaceous nutlet, beaked with the short style ; seed pendulous. 

 Annuals: stems very slender, branching; leaves opposite, or alter- 

 nate, linear and entire, with sheathing membranous stipules. 



