324 ORDER 135. IIYDROCHARIDACE^E. 



3 S. lanceolttta L. Leaves lance-oblong, rarely linear, tapering to the long petiole; 



scape branched; 2 3f ; achcnia obovate-falcate. Swamps, Ya. to Fla. 



4 S. lieterophylla Ph. Leaves linear-lanceolate, rarely some of them with 1 or 3 



base lobes ; scape simple, weak ; achenia narrow, long-beaked. Common S. and W. 



5 S. graminea MX. Scape erect, slender, 5 2(X; leaves lance-ovate to linear, rarely 



sagittate ; pedicels all equally slender ; achenia beakless ; flowers 8 9" diameter. 

 /3. plali/phylla. Leaves lance-ovate ; flowers larger, 1' broad. South. 



6 S. pus ilia N. Scape shorter than the leaves (240 ; leaves linear, shorter than the 



petioles ; flowers few, the fertile but one, deflexed ; stamens about 7. N. J., and S. 



7 S. natans MX. Scape mostly erect, 3 G' ; leaves oval-lanceolate, floating, obtuse. 



3-veined ; lower pedicels longest ; achenia angular, short-beaked. South. 



5. TRIGLOCHIN, L. ARROW-GRASS. Sepals and petals concave, 

 deciduous (green). Sta. 6, very short, anth. large, extrorse. Ova. 1-ovuled, 

 3 6, united and indehisceut in fruit. H Leaves all radical, grass-like 

 Scape jointless, and bractless. Flowers small. July. 



1 X. maritlmum L. Fruit ovate-oblong, grooved, of 6 united carpels ; scape 



longer (9 18') than the leaves. Salt marshes and Lake shores, northward. 



2 T. palikstre L. Fruit nearly linear, of 3 united carpels; scape scarcely longer 



than the numerous and very narrow leaves. Marshes, N. Y., and N. 612'. 



6. SCHEUCHZERIA, L. Sop. and pet, oblong, acute, persistent. Sta. 

 6, with linear anthers. Ovaries 1-2-ovuled, becoming flattened inflated 

 capsules, if Leaves cauline, sheathing at base, linear. 



S. palustris L. A rush-like plant, in swamps, Vt. to 111. (J. Wolf). Root-stock hori- 

 zontal, fleshy. Stem If. Leaves semicylindric, 48'. Flowers yellowish green, in a 

 bracted raceme. Stamen v large, exserted. July. 



ORDER CXXXV. HYDROCHARIDACEJ3. FROGBITS. 



Aquatic Jierbs, with parallel- veined leaves and diclinous flowers solitary or 

 spicate. Perianth regular, 3-6-parted, the inner segments petaloid. Sta- 

 mens 3 12. Ovary adherent, 1-9-celled, with 3, G, or 9 stigmas. Fruit 

 dry or juicy, oo-seeded, indehiscent. 



* Leaves all radical, roundish, floating in stagnant waters LIMNOBIUAT. 1 



* Leaves opposite or verticillate in 3's and 4's on the stems, submersed ANACHARIS. 2 



* Leaves all radical, grass-like, in water VALLISNEUIA. 3 



1. LIMNOBIUM, Rich. FROG'S-BIT. Fls. 8 . Spathes subsessile, the 

 $ 1-leaved, about 3-flwd., the ? 2-leaved, 1-flwd. Perianth showy, white. 

 Sta. 6 12 (mere rudiments in ? ). Ov. 6-9-celled, becoming a co-seeded 

 berry. if x? Stoloniferous. Lvs. on long stalks, subcordate. July, Aug. 

 L. Spoiigia Rich. Lake Ont. (rare), and S. Lvs. 1 1$', purplish and spongy beneath 



2. ANACHARIS, Rich. DITCH Moss. Fls. 3 S ?, solitary. Spathe 

 axillary, bifid. Perianth 6-parted, colored, small, the fertile excessively 

 produced above the adherent ovary into a capillary tube. Style capillary, 

 with 3 large stigmas. Fruit few-seeded, if ^ Wholly submersed. Aug. 



A. Canadensls Plane. Stems filiform, long, forking; very leafy ; leaves linear-ob- 

 long, serrulate, 510" ; tube of the dingy-white fls. 210' long I Streams and bogs. 



