366 FLORA. 



and much enlarged in fruit; style short, 3-parted ; fruiting calyx 6-8 mm. long, the 

 wings nearly flat, not incised; achene oblong, 3-angled, 4 mm. long, inclined to be 

 pointed at both ends, black, smooth, shining. Prairies of 111. and about St. 

 Louis, Mo. Also in the vicinity of Knoxville, Tenn. Naturalized from Europe(?) 

 July-Sept. 



35. Polygonum cristatum Engelm. & Gray. CRESTED FALSE BUCKWHEAT. 

 (I. F. f. 1352.) Perennial, scurfy; stem slender, twining, 0.7-2.5 m. long, more 

 or less branched. Leaves triangular or ovate, 2.5-13 cm. long, acuminate at the 

 apex, undulate, truncate or cordate at the base, rather long-petioled; ocreae cylin- 

 dric-funnelform ; flowers in simple or compound often naked racemes 2.5-13 cm. 

 long; pedicels about 5 mm. long, jointed near the middle; calyx greenish -white, 

 4-5 mm. long, 5-parted, the three outer segments keeled and at maturity winged; 

 stigmas 3 ; fruiting calyx 6-8 mm. long, its wings incised ; achene 3-angled, 

 oblong, black, smooth, shining, about 3 mm. long. Sandy woods and rocky banks, 

 S. N. Y. to Ga., the Ind. Terr, and Tex. Aug.-Oct. 



36. Polygonum Zuccarinii Small. JAPANESE KNOTWEED. (I. F. f. 1353.) 

 Perennial, more or less scurfy; stem stout, erect, woody below, much branched, 

 1-2.5 m - ta ^- Leaves oblong -ovate or ovate- lanceolate, petioled, 5-15 cm. long, 

 acuminate cuspidate at the apex, truncate or subcordate at the base, reticulate- 

 veined on both surfaces, undulate; ocreae oblique, smooth, fugacious; racemes 

 mostly terminal, panicled, 5-10 cm. long, or axillary, many-flowered, more or 

 less pubescent; flowers greenish -white, long-pedicelled; outer segments of the 

 5-parted calyx very broadly winged in fruit; style 3-parted; achene 3-angled, 

 narrowly oblong or oblong-pyramidal, 2.5-3 mm - l n g> black, smooth, shining. 

 Escaped from cultivation in Me., near Philadelphia, Pa., Schenectady, N. Y., N J., 

 and in Ohio. Native of Japan. July-Oct. 



37. Polygonum sagittatum L. ARROW -LEAVED TEAR-THUMB (I. F. f. 

 1354.) Annual, light green; stem slender, weak, decumbent, or climbing over 

 other plants by the abundant recurved prickles which arm its four prominent angles. 

 Leaves lanceolate -sagittate or oblong -sagittate, 1.2-7.5 cm - l n g: obtuse or acute at 

 the apex, slightly rough on the margins, the lower petioled, the upper subsessile; 

 petioles and lower surface of the midribs prickly; ocreae oblique, not ciliate, 

 fringed at the base by a few bristle-like prickles; flowers in rather dense terminal 

 heads or racemes; calyx greenish or rose- colored; style 3-parted to below the 

 middle; achene 3-angled, oblong -pyramidal, thick -pointed, 3 mm. long, dark red, 

 smooth, shining. In wet soil, Newf. and N. S. to the N. W. Terr., south to Fla. 

 and Kans. July-Sept. 



38. Polygonum arifolium L. HALBERD-LEAVED TEAR-THUMB. (I. F. f. 

 1355.) Perennial ; stem ridged, reclining, 3-18 dm. long, the ridges armed with 

 recurved prickles. Peduncles and pedicels glandular or pubescent; leaves broadly 

 hastate, long-petioled, 2.5-25 cm. long, pubescent or glabrous beneath, the apex 

 and basal lobes acuminate; petioles and stronger nerves prickly; ocreae oblique, 

 fringed at the summit with short bristles and at the base with slender prickles; 

 flowers in terminal and axillary heads or racemes; calyx rose-color or greenish. 

 4-parted; style 2-parted; achene lenticular, broadly obovate, 4 mm. long, strongly 

 biconvex, dark brown, smooth, shining. In moist or wet soil, N. B. and Ont. to 

 Minn., south to S. Car. July -Sept. 



7. POLYGONELLA Michx. 



Annual or perennial glabrous herbs, sometimes slightly woody, with branched, 

 usually conspicuously jointed stems, alternate narrow leaves jointed to the mostly 

 naked ocreae, and small white, pink or greenish flowers in slender panicled ra- 

 cemes. Calyx unequally 5-parted. persistent, its segments petalloid, loosely invest- 

 ing the achene or its base in fruit, the three inner calyx-segments often winged. 

 Stamens 8, included; filaments filiform, or much dilated or auricled at the base. 

 Style 3-parted, short or almost wanting stigmas capitate. Achene 3-angled, 

 smooth. Embryo slender, nearly straight in on2 of the angles of the seed. [Dimin- 

 utive of Polygonum.] Five or six species, natives of N. Am. 



Annual ; inner sepals not winged in fruit ; pedicels reflexed. i. P. articulata. 



Perennial ; inner sepals winged in fruit ; pedicels divergent. 2. /*. Americana* 



