560 OEDER CXXXVIII. AKACE^. 



Genus I— SPARGA'OTUM. 19—3. 

 (From 8pargano7i, a band or fillet) 



Flowers monoecioiis. Sterile florets : anient nearly spherical, 

 dense ; perianth 3-leaved. Fertile florets : ament nearly spher- 

 ical ; perianth 3-leaved. Stigma 2-cleft, or simple. Fruit a 

 dry, 1 -seeded nut. 



1. S. America'num, (Nutt.) Stem flexuous, terete, glabrous, sparingly 

 branched. Leaves ligulate, glabrous, thick ; the lower ones carinate, 

 about as long as the stem, the upper concave at the base, erect. Flow- 

 ers in sessile, globular heads ; fertile heads 2 — 5, usually sessile ; sterile 

 ones 6 — 9. Stigma simple, oblique. — U- May — June. In stagnant 

 waters. 12 — 15 inches. Burr-reed. 



Genus II.— TY'PHA. 19—3.. 

 (From tiphos, a bog or marsh.) 



Flowers monoecious, collected into a long, cylindrical spike. 

 Sterile florets : perianth wanting. Stamens united into a com- 

 mon filament. Fertile florets : perianth none. Pericarp pedi- 

 cellate, surrounded at the base with hairs resembling a pappus. 



1. T. latifo'lia, (L.) /S^rm terete, glabrous. Leaves linear, nearly 

 as tall as the stem, sheathing at the base. Flowers in a cyhndrical spike, 

 the upper ones sterile, the lower ones fertile. — If. July — Aug. In 

 stagnant waters. 5 — 6 feet. 



Genus III.— A' RUM. L. 19—12. {Ariscema.) 

 (An Egyptian word.) 



Flotoers monoecious. Sj^cithe 1-leaved, cucullate, convolute 

 at the base. SjMdix naked at the summit, bearing sterile flo- 

 rets in the middle, and fertile ones at the base. Perianth none. 

 Fruit 1-celled, many-seeded. 



1. A. Dracon'tium, (L.) Leaves perhaps never but one, pedate ; 

 leaflets lanceolate, oblong, entire, on long petioles. Spadix subulate, 

 longer than the spathe. — White. U. June. Moist places. 10—12 

 inches. Green Dragon. Ariscema Draconiimn, Schreb. 



2. A. triphtl'lum, (L.) Leaves ternate ; leaflets ovate, acuminate, 

 entire. Spadix clavate, about half as long as the spathe. Fruit sear- 

 let, 3 — 4-seeded. [This species is said to be sometimes dioecious. The 

 A. quinatum differs in no respect from the above, but in its quinnate 

 leaves.] — Purple, striped. U. March — Aj-ril. Rich soils, 10 — 12 in. 



Dragon-root. Wake-rohin. Indian Turnip. A. atro-rubens, Blum. 



3. A. Virgin'icum, (L.) Leaves oblong, hastate, entire, glabrous, 10 

 — 15 iiiclies long; petioles long, sheathing at the base ; spathe incurved. 

 Spadix about as long as the spathe, Fi'uit many-seeded. — U- April 



-May. Marshy soils. Very common. 12— 18 inches, 



Peltametra Virginica, Raf. 



