32 MISSOURI BOTANICAL GARDEN. 
Scape branching, longer than the linear submerged 
leaves. S. filiformis. 
Stamens 12 or 13. S. demersa. 
c. Filaments slender, glabrous; leaves entire; achenia cuneate 
quadrate. S. Sanfordit. 
* ** Fertile pedicels much thickened, ascending; filaments slender, glab- 
rous; scape shorter than the leaves. S. Mexicana. 
2. Sepals of the pistillate flower erect and accrescent; petals with a 
brownish purple spot at the base. S. Montevidensis. 
SYNOPSIS OF THE SPECIES OF SAGITTARIA NORTH OF 
MEXICO. 
A. Sepals of the pistillate flower refiexed after flowering, not enlarg- 
ing in fruit; petals white. 
§ Sagittifoliae. Leaves sagittate or rarely when submerged entire, or 
reduced to bladeless phyllodia; filaments glabrous, not enlarged at the 
base; sterile pedicels longer than the fertile. 
* Achenium obovate cuneate, the beak minute, erect, retrorse; fila- 
ments shorter than or equaling the anthers; basal lobes less than half 
the length of the leaf; bracts slightly connate. 
S. arrrouia Nutt. in herb.— S. sagittifolia minor Pursh, 
Flora Amer. Sept. 2: 395 (1814).* WS. variabilis 
var. hastata forms b and ¢ in part, Macoun, Cat. Can. 
Pl., 4: 77, 78 (1888). 
Terrestrial, or emergent aquatic, weak, ascending, 2 to 4 
dm. high; petioles rather stout, usually curving outward ; 
blade of leaf 6 to 12 or 18 cm. long, arrow-shaped, acute, 
the margin mostly straight or arcuate, basal lobes diverg- 
ent, acute or acuminate; scape weak, ascending, simple or 
rarely branched; bracts lanceolate, acute, 8 to 20 mm. 
long, scarious margined and obscurely veined, often 
reflexed; 1 to 3 lower verticils pistillate; fertile pedicels 
ascending, 15 to mostly 25 mm. long, or sometimes almost 
wanting; fruiting head round, 8 to 15 mm. in diameter; 
achenium 2 mm. long, tumid winged on both margins, the 
* Pursh gives the range as ‘‘Pennsylvania to Carolina;’’ but Dr. 
Engelmann in his manuscript notes says that Pursh’s plant is from the 
Rocky Mountains and that it ‘‘seems to be exactly like’’ a specimen 
collected by Nuttall. 
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