455 
2. SAGITTARIA L. (ARROW-HEAD.) 
Stoloniferous herbs, with milky juice, long-petioled sheathing leaves 
(often without blade), mostly simple stems bearing one to few whorls 
of membranaceous-bracted flowers usually in threes, staminate flowers 
above, indefinite (rarely few) stamens, many ovaries crowded in a 
spherical or sub-triangular depressed head on a globular receptacle, 
and forming in fruit flat membranaceous-winged achenes. 
*Flowers monecious or diawcious, with the lower whorls pistillate: slamens covering the 
receptacle: sepals spreading or reflexed in fruit, 
+ Filaments numerous, as long as the linear-oblong anthers or longer: bracts distinct: 
Fruiting heads larger than in the nest, 
1. S. variabilis Engelm. Scape (1 to 12 din. high) angled, with one or more of the 
lower whorls fertile: leaves very variable, almost always sagittate: pedicels of fer- 
tile flowers at least half the length of the sterile ones: petals white: filaments gla- 
brous, nearly twice the length of the anthers: achenes obovate, winged on both 
margins, with a long curved or usually horizontal beak 4 or 4 itslength, CS. sagil- 
tefolia L., var. variabilis Micheli.)—Throughout Texas. Var, ANGUSTIFOLIA Engelm., 
near Brazos Santiago, has narrow leaves with long and linear diverging lobes. 
2. S. lancifolia L. Scape 6 to 15 dm, high, with several of the lower whorls fer- 
tile: leaves lanceolate or lance-oblong (rarely linear), with tapering base (15 to 45 
em. long), on a stout petiole, the nerves arising from the very thick midrib: bracts 
ovate, acute, or acuminate: pedicels slender, the fertile scarcely shorter than the 
sterile ones: filaments pubescent: achenes falcate, winged on the back, pointed with 
an incurved beak.—Extending from the east through Texas to southern Mexico, 
++ Filaments very short: fruiting head small: bracts connate. 
3. S. graminea Michx. Scape 1 to 6 dm. high: phyllodia flat, mostly broadly 
linear, acuminate: leaves ovate-lanceolate to linear, on long slender petioles: bracts 
obtuse: whorls of flowers few, all staminate or the lower fertile; pedicels slender, 
spreading, nearly equal: filaments 15 to 20, glandular pubescent: achene small, nar- 
rowly obovate, almost beakless, winged on the back, flat and scarcely costate on the 
sides.—Extending from the Atlantic States into Texas. 
** Fertile flowers perfect: stamens 9 to 15 at the base of the receptacle: sepals erect 
and embracing the fruit. 
4. S.calycina Engelm. Scape weak, 1 to 2dm. high: leaves broadly halberd- 
shaped, with spreading lobes: pedicels about equal, recurved in fruit: bracts orbicu- 
lar; filaments slightly rough, as long as the anthers: achenes obovate, with a short 
horizontal style.-—Extending from the North Atlantic States to Texas. Var. FLUI- 
TANS Gray, found in ponds and slow-running waters of western Texas, has lance- 
linear floating leaves. 
3. ECHINODORUS Richard. 
Mostly annuals, with the habit of Sagittaria, naked sparingly 
branched or simple stems, short pediceled perfect flowers in 3 to 8 
whorls, 6 to 21 stamens, and the several or many ovaries imbricated in 
a head and forming thick and ribbed achenes in fruit. 
1. BE. parvulus Engelm. Scapes 2.5 to 7 cm. high: leaves lanceolate or spatulate, 
acute, 1 to 3 cm. long: umbel single, 2 to 8-flowered; pedicels reflexed in fruit: 
