Sagittaru. CXXXVIII. ALISMACEiE. 527 



aggregated, and becoming, in fruit, as many compressed, margined 

 achenia collected into a globose head. — % acaukscent. Lvs. radical^ 

 generally sagittate. Fls. in verticils of 3, the sterile ones near the sum- 

 mit of the scape., fertile below them. 



1. S. SAGiTTiFOLiA. Arrowhead. 



Lvs. lanceolate, acute, sagittate, lobes lanceolate, acute. — A curious aquatic 

 plant, conspicuous with its large white flowers among the rushes and sedges of 

 sluggish waters. Can. and U. S. Root fleshy and farinaceous. Leaves 3 — 10' 

 long including the lobes which are nearly half this length, J — 4 or 5' wide, 

 smooth and entire. Scape 1 — 2f high, branching, obtusely 3-angled. Flowers 

 generally in 3s, the upper ones barren. Petals 3, large, roundish, white and 

 very delicate. July, Aug.— The leaves, &c., are exceedingly variable, and Dr. 

 Torrey has appended the following, as varieties : 



/?. laiifiUa. Lvs. broad-ovate, rather obtuse, with straight, ovate, slightly 

 acuminate lobes. 



y. hastata. Lvs. oblong-lanceolate, acute, with spreading, lanceolate, long, 

 acuminate lobes ; fis. mostly dicecious. 



6. gracilis. Lvs. linear, with linear, very long, acute and spreading lobes. 



e. pviescens. Plant distinctly pubescent, in all its parts ; lvs. and their lobes 

 ovate. 



2. S, RiGiDA. Pursh. Brittle-leaved Arrowhead, 



Lvs. narrow-lanceolate, carinate, rigid, very acute at both ends ; scape 

 branching.— N. York. Growing in water even to the depth of 7 feet, accord- 

 ing to Dr. Beck. Leaves remarkably dissimilar to those of the foregoing spe- 

 cies, f) — 6' in length, one in width, thick and brittle, and on stout, rigid petioles, 

 prolonged according to the depth of the water. Flowers numerous and large) 

 with 3, white, rounded petals ; fertile ones on short peduncles. July. 



3. S. HETEROPHYLLA. Pursh. Various-lcaved Arrowhead. 



Lvs. smooth, linear and lanceolate, acute at each end, rarely some of them 

 elliptical and sagittate, with lobes linear and divaricate; scape aira-gle, few-flow- 

 ered, fertile flowers subsessile.— Muddy shores. Middle States. Leaves 2 — 4' 

 long, i as wide, on petioles rather longer than the scape which is seldom a foot 

 high. Flowers iew, the three lower ones fertile and very nearly sessile, all with 

 roundish bracts at base. July. 



4. S. SIMPLEX, (acutifolia and graminifolia. Pursh.) Linear Sagittaria. 

 Lvs. erect, simple, linear and lance-linear, sheathing, hyaline ancl cellular 



at base, attenuated to a long, acute point ; scape simple, longer than the leaves ; 

 fs. § or (J> 9 , in whorls of 3, 4 or 5, subterminal and terminal ; sta. in the bar- 

 ren flowers 12 — 15; bracts minute. — Muddy shores of ponds and rivers. Me. ! to 

 N. J., N. Y. ! W. to 111. A species almost as variable as S. sagittifolia, to which 

 it is indeed appended by Hooker as another class of varieties. Leaves 4 — 7' 

 high, usually very narrow. Scape 5—8' high. Flowers 9—18, 8—9" diam. 

 Petals rormdish, white. 



5. S. oBTusA. Willd. Blunt Arrowhead. 



L^-s. broad-ovate, sagittate, rounded and mucronate at the apex, lobes ob- 

 long, obliquely acuminate, approximate and not spreading; /5. (^9; scape 

 simple, the sterile branched at the base; tracts ovate, acute. — Ditches, ponds 

 and marshes, Penn. to Va. W. to Ohio. Juice milky, exuding from the wounded 

 stem or leaves, and hardening into a pellucid gum. Scape 1- 2f high. Leaves 

 on long, radical, channeled petioles, lamina 3 — 5' by 2 — 3'. Flowers white, sho-vnT-. 



6. S. PUsiLLA. Nutt. Puny Arroivhead. 



Petioles (leaves'?) short, linear, obtuse, summits only foliaceous ; scape 

 simple, shorter than the leaves ; fis. few, fertile one solitary, deflexed ; sta. mostly 

 7. — A diminutive species on muddy banks, N. Y. to Ga. Leaves rarely subu- 

 late, an inch or two long, less than a line wide. Scape 2 — 4' high. Flowers 

 4 — 7, the lowest one only fertile. Aug. 



7. S. NATANS. Michx. Floating Sagittaria. 



Lvs. floating, oval-lanceolate, obtuse, 3-veined, tapering to the base, lower 

 45 



