SAGITTARIA. CXXXVIII. ALISMACE^E. 527 



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

 achenia collected into a globose head. % acaulcscent. 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. Arrmcheod. 



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: 



0. laiifolia. Lvs. broad-ovate, rather obtuse, with straight, ovate, slightly 

 acuminate lobes. 



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

 acuminate lobes ; fls. mostly difficious. 



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



e. pubescens. Plant distinctly pubescent, in all its parts ; Ivs. 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, 5 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-leaved Arrowhead. 



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

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

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

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

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

 roundish bracts at base. July. 



4. S. SIMPLEX, (acutifolia and graminifolia. Pursh.} Linear Sagittana. 

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



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

 fls. or J* 9 , m 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 roundish, white. 



5. S. OBTUSA. Willd. Blunt Arrowhead. 



Lvs. broad-ovate, sagittate, rounded and mucronate at the apex, lobes ob- 

 long, obliquely acuminate, approximate and not spreading ; fls. tf 9 1 scape 

 simple, the sterile branched at the base ; bracts 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, showy. 



6. S. PUSILLA. Nutt. Puny Arrowhead. 



Petioles (leaves 7) short, linear, obtuse, summits only foliaceous ; scape 

 simple, shorter than the leaves ; fls. 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 



