ALISMACE^E: (WATER- PLANTAIN FAMILY.) 439 



Filaments slender awl-shaped, longer thar* the anthers : scape simple 01 branched. 



1. S. falcata, Pursh. Scape l-5 high, with several of the lower 

 whorls fertile ; bracts ovate or orbicular ; pedicels slender, the fertile recurved in 

 fruit; filaments hairy; achenia obocate-falcate, pointed with a sliart incurved beak ; 

 leaves lanceolate or lance-oblong, all with a tapering base, thick (6' -18' long, and 

 on a long and stout petiole), the nerves mostly arising from the very thick midrib. 

 (S. lancifolia, Michx.) Swamps, Virginia and southward. Known at once by 

 its coriaceous and large, thick-ribbed, never sagittate leaves, &c. 



2. . variabilis, Engelm. Scape (|-4high) 12-angled, with one or 

 more of the lower whorls fertile ; bracts pointed ; pedicels of the fertile floivers 

 about half the length of the sterile ones ; petals with wliite claws ; filaments glabrous, 

 ncarlv twice the length of the anthers ; achenia obovate, with a long and curved 

 beak of J or ^ its length ; leaves very various, mostly sagittate. (S. sagittifolia, 

 Amer. auth., frc. The European species has the fertile pedicels only J or ^ the 

 length of the sterile, the claws of the petals purple-tinged, the filaments not 

 longer than the anthers; the achenia almost orbicular, very broadly winged, 

 and short-beaked.) In water or wet places; very common. Excessively 

 variable in size and foliage : the following are the leading forms. Var. OBTt8A 

 (S. obtusa, Willd.) is large, dioecious ; the broadly sagittate leaves obtuse, - 

 1 long. Var. LATIF6LIA (S. latifolia, Willd.) is large, monoecious, with 

 broad and acute sagittate leaves. Var. DIVERSIF6LIA, with some leaves 

 ovate-lanceolate, others more or less sagittate. Var. SAGITTIF6LIA is the or- 

 dinary form, with narrowly halberd-shaped or sagittate leaves (including S. 

 hastata, Pursh). Var. ANGUSTirdLiA has the narrow leaves with long and 

 linear diverging lobes, and a larger more horizontally beaked fruit. Var. GRA- 

 CILIS (S. gracilis, Pursh) is the most slender form, with nearly linear leaves and 

 lobes. See Addend. 



# * Filaments very short, with a very broad glandular base : scape commonly simple. 



3. S. hetcroptiylla, Pursh. Scape weak, at length mostly procum- 

 bent ; bracts roundish, obtuse ; the lowest whorl of fertile flowers, which are 

 almost sessile ; the sterile flowers on long pedicels ; achenia narrowly obovate, long- 

 beaked. llather common, at least southward, and nearly as variable in foliage 

 as the last. Var. ELLIPTICA has broad leaves (sometimes 6' long and 5' wide), 

 either obtuse or cordate at the base, or sagittate. Var. R^GIDA (S. rigida, 

 Pursh) has stout petioles and rigid narrowly lanceolate blades, acute at both 

 ends. Var. AXGUSTir6LiA has nearly linear leaves. Var. FLtiiTAXS lias 

 narrowly linear and delicate floating leaves. 



4. S. Simplex, Pursh. Scape very slender, erect (3'- 20' high), the 

 lower whorls fertile ; bracts triangular, rather obtuse, the upper ones connate ; 

 pedicels all slender, the sterile and fertile of equal length ; achenia small, obovate, nar- 

 rowly winged, brakless ; leaves varying from ovate-lanceolate to linear, rarely 

 sagittate. (S. acutifolia, Pursh, c.) Rather common, especially southward. 

 Flowers much smaller than in any of the foregoing. 



5. S. piisilla, Nutt. Dwarf; scape (l'-3' high) shorter than the linear 

 or awl-shaped entire leaves (their proper blade obscure and obtuse or none) ; 

 flowers on/y 2 - 9, on slender pedicels the fertile recurved after flowering , siainer* 



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