SAGITTARIA AND LOPHOTOCARPUS. 31 
ANALYTICAL KEY. 
1. Sepals of the pistillate flower reflexed or spreading, not accrescent. 
* Fertile pedicels slender, ascending, neither much thickened nor 
reflexed in fruit. 
+ Leaves sagittate; filaments glabrous, not dilated. 
++ Basal lobes equaling or shorter than the middle one. 
= Beak more than one-fourth the length of the achenium. 
Fertile pedicels much shorter than the bracts; leaves ample; 
beak of the achenium stout, erect. S. longirostra. 
Fertile pedicels longer than the bracts; leaves with linear 
lobes; beak of the achenium erect. S. Engelmanniana. 
Beak of the achenium lateral, horizontal or oblique. VS. latifolia. 
= = Beak of the cuneate obovate achenium very short, erect, re- 
trorse; basal lobes very short. 
Petioles short and curving; bracts long, scarious margined; 
terrestrial, or emergent aquatic. 8S. arifolia. 
Petioles long and slender; bracts short; submerged aquatic 
with flowers at the surface of the water. S. cuneata. 
++ ++ Basal lobes more than half the length of the leaf. 
Basal lobes 2 or 3 times as long as the middle one; stamens 
less than 24; seed coat punctate. S. longiloba. 
Basal lobes less than twice as long as the middle one; stamens 
80 or more; seed coat not punctate. S. Greggii. 
+ + Leaves entire or hastate. 
++ Filaments slender, not dilated; leaves pseudo-penninerved. 
Filaments glabrous; bracts short, densely papillose; achenium 
short-obovate. S. papillosa. 
Filaments glabrous; achenium falcate; fertile pedicels longer 
than the sterile. 8. ambigua. 
Filaments cobwebby pubescent; achenium falcate. S&S. lancifolia. 
++ ++ Filaments dilated, pubescent; veins free to the base of the leaf. 
a. Fertile flowers sessile; scape geniculate at the lowest verticil; 
achenium stoutly beaked. S. rigida. 
b. Fertile pedicels shorter than the sterile; achenium 3 mm. long, 
broadly winged, the sides smooth.— In South Carolina. 
S. macrocarpa. 
c. Fertile pedicels about as long as the sterile. 
Leaves terete and mostly bladeless.—Species of the Atlantic 
coast. S. teres. 
Leaves rigid, elliptical-linear, somewhat triquetrous. S. cristata. 
Leaves neither rigid nor terete. S. graminea. 
** Fertile pedicels much thickened, reflexed in fruit. 
a. Filaments dilated, pubescent. S. platyphylla. 
b. Filaments dilated, glabrous. 
Stamens 7 or 8. 
Scape simple. S. subulata. 
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