roLYGONUM- ponirus. 127 



sen"ega, (seneca snake-root, mountain-flax, r. or w. J. %) stem erect, simple, 

 leafy; leaves alternate, lanceolate; spike terminal, filiform; flowers alter- 

 nate, not crested. Var. albida, leaves lanceolate or oval; spike somewhat 

 crowded; flowers white, sub-sessile. 8-14 i. 



polvgaina, (ground-flower, p. J. %.) stems numerous; leaves linear-oblong, 

 alternate downwards; racemes terminal and lateral, elongated; flowers 

 sessile; radical racemes procumbent, with apterous flowers. 4-8 i. 



jmrpu'rca, (r. Ju. ©.) stem fastigiately branched ; leaves alternate, oblong- 

 linear ; flowers beardless, imbricated in obtuse cylindrical spikes ; rachis 

 squarrose ; wings of the calyx cordate, ovate, erect, twice as long as the 

 capsule. 12-18 i. Woods and hill-sides. 



lutca, (yellow milkwort, y. S. ^.) stem simple or branched ; lower leaves spat- 

 ulate, upper ones lanceolate ; flowers in globular heads ; wings of the calyx 

 ovate, mucronate ; bracts shorter than the flowers. 8-16 i. Pine barrens. 



POLYGONII.M. 8—3. (PohjgonecB.) [From polus, many, and gone, a joint, on account of the 

 nianyjointsin its stem.] 

 avicvla're, (knot-grass, w. M. %.) leaves lanceolate, scabrous at the margin; 

 stipules short, laciniate ; stem procumbent ; flowers sub-sessile, axillary, 

 minute. 6-12 i. 

 fagop"ijrum, (buckwheat, r-w. Ju. ©.) racemes panicled ; leaves heart-sagit- 

 tate ; stem erectish, unarmed ; angles of the seeds equal. 1-2 f. Ex. 

 orie>i"t,ale, (prince's feather, r. Au. ©.) stem erect; leaves very large, peti- 

 oled, ovate, acuminate, minutely pubescent ; stipules hairy, somewhat sa- 

 bre-form ; flowers in crowded, terminal spikes. 4-5 f. Old fields and road- 

 sides. Flowers in large, pendulous, crimson spikes. Naturalized. 

 POLYMNIA. 17^. (Corymbiferm.) [Named from Po/i//(!/OT7i!a, the muse of eloquence.] 

 canaden"sis, (y. J. %.) viscid-villose ; leaves denticulate, acuminate, lower 

 ones pinnatifid, upper 3-lobed or entire. 2-4 f. Flowers in a loose, termi- 

 nal panicle. Shady hills. 



POLYPOUIUM. 21—1. iPilices.) [From polus, many, and pov^, foot, because it has many 

 roots.] 

 vulga're, (polypod, Ju. %.) frond deeply pinnatifid; divisions lance-linear, 

 obtuse, crenulate, approximate, upper ones gradually smaller; fruit-dots 

 solitary ; root chaffy. 8-12 i. 



POLYTHRICmUM. 21—2. (Musci.) [From ;?oZms, many, and ;/in>, hair ; so called from its 

 resemblance to hair.] 

 jwiiperi'num, (hair-cap moss, M. %.) stem generally simple; leaves lance- 

 linear, entire, flattish, somewhat spreading; the apophysis depressed. In 

 dry woods, &c. 

 POMARIA. 10—1. (LeguminoscB.) 

 glandulo'sa, (y. b.) branching, glandular-punctate; branches slender, sub- 

 pubescent; leaves abruptly bi-pinnate ; leafets ovate, oblique at the base, 

 entire, .sessile, sub-pilose, smooth and pale-green above. S. 

 PONTEDERIA. 6—1. (Narcissi.) [Name from an ancient botanist, Pontidera.] 

 corda'ta, (pickerel-weed, b. Ju. % ) leaves heart-oblong, obtuse ; spike man3»- 

 flowered, compact ; divisions of the corolla oblong. Var. angustifolia, 

 leaves elongated, triangular, truncate, and sub-cordate at the base. 1-2 f. 

 POPULUS. 20—8. (AmentacecB.) [The origin of the name is doubtful.] 

 tremuloi'des, (white poplar, American aspen, Ap. 1^.) leaves heart-roundish, 

 abruptly acuminate; tooth-serrulate, glabrous, a little pubescent at the map- 

 gin, with 2 glands at the base on the upper side; petioles compressed, in 

 the young state silky. 20-30 f. 

 balsamifera, (balsam poplar, Ap. l^.) leaves ovate, acuminate, white, and net- 

 veined beneath ; buds resinous. 70-80 f. 

 angulata, (balm of Gilead, Ap. I-j.) leaves ovate-deltoid, acuminate, glabrous, 



branches wing-angled. 80 f. 

 dilatata, (Lombardy poplar, Italian poplar, Ap. l^.) leaves glabrous both sideSj 

 acuminate, serrate, deltoid, the breadth equal to, or exceeding the length* 

 branches erect, close to the stem. It is said no pistillate plant of this spe- 

 cies has been brought to America; consequentlv no seeds are obtained frora 

 it. 40-80 f. Ex. 

 32 



