40 FLORA. 



heads 3-7, sessile or the lowest peduncled, axillary or the peduncles and branches 

 axillary ; style I ; stigma I (rarely 2) ; fruiting heads 1225 mm i n diameter ; nut- 

 lets fusiform, 4-6 mm. long, 3 mm. thick, often strongly contracted at the middle, 

 tapering into the style ; scales oblong, as long as the nutlets or shorter, the exterior 

 ones narrower ; stalk of fruit 2 mm. long or more. In bogs or shallow water, N. S. 

 to Ont. and Br. Col., south to Fla. and La. June Aug. 



Sparganium androcladum fluctuans Morong. Floating in deep water with long 

 slender stems and thin leaves 2-7 mm. wide ; inflorescence usually sparingly branched ; 

 fruiting heads 8-12 mm. in diameter. In cold ponds, N. B. to Penn. 



3. Sparganium simplex Huds. SIMPLE-STEMMED BUR-REED. (I. F. f. 140.) 

 Stem slender, 3-60 cm. high, simple. Leaves more or less triquetrous, 4-8 mm. 

 wide; inflorescence 2-20 cm. long; staminate heads 4-6; pistillate 2-6, sessile or 

 the lowest peduncled ; fruiting heads 10 16 mm. in diameter ; nutlets fusiform or 

 narrowly oblong, obtusely angled at the apex, more or less contracted in the middle, 

 smaller than those of the preceding species and more tapering at the summit ; scales 

 denticulate, about one-half as long as the nutlets ; stigma linear, as long as the style or 

 shorter, rarely 2 ; stalk of fruit about 2 mm. long. Borders of ponds and streams, 

 Newf. to Br. Col., Penn., Mont, and Cal. June-Aug. 



Sparganium simplex angustifblium (Michx.) Engelm. Floating in deep water. 

 Leaves very long, 1-3 mm. wide, their sheaths often inflated at the base ; staminate and 

 pistillate heads 1-4 ; fruiting heads 6-15 mm. in diameter. In mountain lakes and slow 

 streams, Newf. to Ore., N. Y. and Cal. 



4. Sparganium minimum Fries. SMALL BUR-REED. (I. F. f. 141.) Float- 

 ing, stems very slender, o.l-I m. long. Leaves thin and lax, 1-5 mm. wide ; inflor- 

 escence 2 cm. or more long ; staminate heads 1-2 ; pistillate, 1-3, sessile, axillary, 

 supra- axillary or the lowest on an axillary peduncle ; ripe fruiting heads 410 mm. 

 in diameter ; nutlets ovoid, slightly triangular, tapering abruptly into the style, 

 2-4 mm. long, twice as long as the denticulate scales ; stigma oval, often oblique, 

 about as long as the style; stalk of the nutlet 0.5-1 mm. long, often apparently 

 none. In ponds and streams, N. B. to Man. and Ore., south to N. J., Mich, and 

 Utah. Also in northern Europe. Dwarf forms, growing out of water, sometimes 

 occur with stems 3'-6' high. June-Aug. 



Order 2. NAIADALES. 



Aquatic or marsh herbs, the leaves various in form. Flowers perfect, 

 monoecious or dioecious. Perianth present, or wanting. Parts of the 

 flower mostly unequal in number. Carpels i or more, mostly distinct and 

 separate (united in Vallisneriaceae ; united at least until maturity in 

 Scheuchzeriaceae) ; endosperm none, or very little. 



Perianth, if present, inferior ; carpels mostly distinct. 

 Perianth-segments, when present, herbaceous. 



Carpels distinct ; aquatic herbs. Fam. i. Naiadaceae. 



Carpels united until maturity; bog plants ; flowers racemed or spiked. 



Fam. 2. Scheuchzeriaceae. 

 Perianth of 2 series of segments, the outer green, the inner mostly white. 



Fam. 3. Alismaceae. 

 Perianth superior; carpels united. Fam. 4. Vallisneriaceae. 



Family i. NAIADACEAE Lindl.* 



Immersed aquatic plants with slender, often branching, leafy stems, the 

 leaves flat or filiform, and perfect, monoecious or dioecious, spicate axil- 



* Contributed by the late Rev. THOMAS MORONG. 



