WAIADACE^. 



367 SPARGANIITM. 



/3. angustifolia, (T. anofustifolia. authors) ; sterile and fertile spikes a little 

 remote (4 — 2 inches). Found in the same situations with the former. A 

 well marked variety, but differing only in the more slender habit, and less 

 complete development of its parts. 



2. SPARGA'NIUM. 



Spadix of flowers globose. Sterile. — Calyx 3 — Gsepaled. 

 Ferlile. — Calyx 3 — G-sepaled ; utricle turbinate, acuminate, 

 1 — 2-seeded. 



Gr. o-Tragyavov, a band or fillet; in reference to the long, ribbon-like leaves. 

 Root perennial. Fls collected in several dense, roundish heads, the sterile 

 heads above the fertile. 



1. S. RAMO'SUM. 



Leaves triangular at base, their sides concave ; common flower-stalks 

 branched ; stigmas 2, linear. Grows in pools and ditches where it is con- 

 spicuous among other reedy plants for its globular burrs of flowei-s. Stem 

 1 — 2 feet high, flexuous, round, with a few branches above. Leaves ^ — 2 

 feet long, 4 — 8 lines wide, linear, arising above the stem, triangular towards 

 the base, and svvord-forni upwards, tapering, but obtuse. Heads of flowers 

 light green ; fertile ones 2 — -5, the lowest generally raised on a short, axillary 

 stalk ; sterile ones above, more numerous, smaller, sessile. Aug. Burr Reed. 



2. S. SIMPLEX. Smith. S. Americana. J^utt. 

 Loic(r leaves eqnal with, or exceeding the stem which is nearly simple; 



floral ones concdiVC at base and erect; stigma always simple, ovate oblong, 

 oblique, scarcely more than half the length of the style. Ponds and lakes. 

 Stem 1 — 2 feet high, simple or divided ai base. Leaves mostly radical, 1 —2^ 

 feet long, carinate at base. Ferlile heads mostly sessile, generally 3, below 

 the several barren ones. Scarcely distinct from the preceding. Aug. 



Simple Burr Reed. 



3. S. NATANS. Smith. S. angustifolium. Mx. 

 Leaves floating, flat; cnmmonjloirer-stalk s\mp]e; ^iiVma ovate, very short; 



head of .sterile flo2/^ers subsolitary. Lakes and pools. Stem long and slender, 

 and, with the leaves, floating upon the surface of the water. Leaves thin and 

 pellucid. Heads of fertile flowers axillary , generally 2, mostly sessile. Sterile 

 cluster terminal. Aug. Floating Burr Reed. 



ORDER CXXXIX. N.AIADACE.E. The Pond-wecd Tribe. 



Fh- — Perfect or monercinus. Calyx 2 — 4-sepaled or 0. 



Sta. — Definite. Ovaries. ], or2 — 4, free, l-ovuled. Sii^ma simple, often sessile. 

 Fr. — Dry, inclehiscent, l-eelled, ]-seeded Spcrf pendulous. AlbumenO. 

 Water plants, with cellular leaves and inconspicuous flowers. 



Conspectus of the Genera. 



( solitary, diclinous, monandrous. . Aajas. 2 



fO. Flowers axillary, I 2 together, a sterile and fertile one. . 7.annicheUia. 3 



J short, S-flowered, borne on a long, tortuous peduncle. . . li'ippia. 4 



1 linear, bearing the monoecious flowers in a double row. . . Zostera. 1 



Spadix [cylindric, covered with perfect, tetramerous flowers. . . rotamogeton.5 



