192 



ORDER XCVn. POLYGONACE.E BUCKWHEAT-TRIBE, 



In the axils of the leaves, greenish -white, sometimes reddish-white. A common 

 little weed, in waste grounds and along road-sides. Stems 4' 10' long. June 



i. An. 



2. P. tenue. 



Slender Knot-grass. 



Stem erect, slender, sparingly branched, acutely angled ; leaves narrow- 

 linear, sessile, erect, very acute; stipules tubular, fringed ; flowers very small, 

 greenish-white, often solitary, nearly sessile ; stamens 58. A slender species, 

 4' 12' high, not uncommon in dry, sandy soils. July Sep. An. 



* * Flowers pedicellate, spicate, arising from truncate bracts. 



3. P. articulatum. 



Joint-weed. 



Stem erect, slender, branching ; leaves linear-subulate, deciduous ; flowers 

 in long, slender, panicled racemes, rose-color, solitary, nodding, on filiform pe- 

 duncles, proceeding from the imbricate, truncate bracts; stamens 8; styles 3; 

 fruit acutely triangular, smooth and shining. A singular little plant apparently 

 leafless, and covered with a profusion of small, rose-colored, nodding flowers. 

 Stem 4' 12' high. Common in sandy soils near the sea-coast. Aug. An. 



* * * Flowers in terminal or axillary spikes. Leaves lanceolate, varying 

 to obovate. 



4. P. Hydropiper. 



Water-Pepp er. 



Mild Water-Pepper. 



Smooth; stem erector ascending, simple or branching; leaves lanceolate, 

 entire, acuminate, punctate with pellucid dots, waved and rough on the mar- 

 gin ; stipules inflated, fringed ; flowers pale greenish-white, in loose, interrupted, 

 elongated, nodding spikes ; stamens 6 8 ; styles 2 3, united at base ; fruit len- 

 ticular or triangular. A common plant, whose intense acridity is universally 

 known. It grows in low grounds and damp situations generally. Stem 12 ft. 

 high. Aug. Sep. 



5. P. hydropiperoides. 



Stem mostly smooth, erect or ascending, often decumbent and rooting at 

 base ; leaves lanceolate, somewhat hairy, or ciliate ; stipules hairy, long- fringed ; 

 flowers reddish, in slender, loose and weak spikes ; stamens 7 8 ; styles 8, 

 united below ; fruit triangular. A species somewhat resembling the last, but 

 destitute of its acrid properties. Stem 12 ft. high. Swamps and low grounds. 

 July Aug. Per. 



6. P. Pennsylvanicum. Pennsylvanian Knot-grass. 



Stem erect, branching, smooth below ; branches and peduncles more or less 

 covered with glandular hairs ; leaves lanceolate, long-acuminate, petiolate, 

 roughish on the margin and mid-vein ; stipules smooth, not ciliate ; flowers 

 rose-colored, pedicellate, in oblong, nearly erect, crowded spikes ; stamens 6 

 8 ; style 2-parted ; fruit lenticular. A common species in low, moist situations. 

 Stem 14 ft high. July Oct. An. 



7. P. Persicaria. 



Spotted Knot-weed. 



Stem erect, branching, smooth ; leaves lanceolate, acuminate, petiolate, 

 entire, usually marked with a large, heart-shaped, brown spot near the centre ; 

 stipules fringed; flowers rose-color, in short, dense, oblong, terminal spikes; 

 peduncles generally smooth ; stamens mostly 6 ; styles 2, united nearly half 

 way. A common species in wet grounds and waste places, especially distin- 

 guished from the last by its spotted leaves and fringed stipules. Stem 13 ft. 

 high. June Aug. An. 



8. P. orientale. 



Prince's Feather. 



Stem tall, erect, branching, somewhat hairy ; leaves ovate, acuminate, pe- 

 tiolate; upper stipules hairy, somewhat salver-form; flowers large, open, rose- 

 colored, in long, nodding, showy spikes ; calyx 5 parted ; stamens 7 ; style 2- 

 cleft ; fruit lenticular. A tall and very showy plant, 4 8ft. high, frequently 

 found in waste grounds, and very often cultivated. Aug. An. 



9. P. amphtbium. Amphibious Knot-weed. 



Stem ascending, prostrate, or decumbent at base, rooting at the lower joints; 

 leaves oblong-lanceoiate, or oblong, varying from acute to nearly obtuse, taper- 

 ing at base, or somewhat cordate ; flowers rose-color, in oblong or ovoid, dense, 

 terminal spikes; stamens 5; styles 2; fruit flattened, smooth. A very variable 

 Bpecies, growing in and about ponds and stagnant water. There are two prin- 

 cipal varieties. Var. aqudticum has long, jointed, rooting stems, creeping in 

 the mud, or floating in the water; leaves large, nearly obtuse, long-petioled. 

 Var. terrestre grows around the borders of ponds, and has a more or less hairy 

 stem, erect or ascending, with acute leaves ; upper ones on very short petioles. 

 July Aug. Per. 



10. P. Virginianum. Virginian Knot-weed. 



Stem erect, simple, smooth below, slightly hairy above ; leaves large, ovate, 

 or ovate-lanceolate, acuminate, rounded at base, on short petioles, ciliate ; sti- 

 pules truncate, hairy, fringed ; flowers small, greenish-white, remote, brncted, 

 in a long, slender, terminal spike, which sometimes has 12 short branches. 

 A common species in shady thickets, distinguished by its large, broad leaves, 

 and its very long and slender spike. Stem 2 3 ft. high. July Aug. Per. 



* * * * Flowers in somewhat capitate clusters or loose racemes. Leaves 

 cordate or sagittate. 



11. P. sagittatum. Arrow-leaved Bindweed. 



Stem weak, ascending or prostrate, square, with the angles bristly backward ; 

 leaves sagittate, entire, acute, with the mid-vein prickly beneath ; stipules 

 smooth ; flowers small, whitish, generally tinged with rose-color, in small, ter- 

 minal heads, on long, slender, smooth peduncles ; stamens mostly 8 ; styles 3 ; 

 fruit acutely 3-angled. A common rough species in wet grounds, supporting 

 itself on other plants by its prickly stem, which is 1 2ft. long. June Aug. 



An. 



12. P. arifolium. Halbert-leaved Bindweed. 



Stem weak, ascending, 4-angIed ; angles prickly backward; leaves hastate, 

 entire, acuminate, on long petioles; flowers rose-colored, in few-flowered, loose, 

 slender racemes, terminating the branches; peduncles rough, with stiff, glandu- 

 iar hairs; calyx sometimes 4-parted ; stamens 6; styles 2 ; fruit lenticular. A 

 prickly species, like the last, supporting itself by its prickles. Low grounds. 

 Not uncommon. Stem 1 2 ft high. Aug. An. 



13. P. Convolvulus. 



Blaclt Bindweed. 



Stern angular, twining or prostrate, somewhat rough, naked at the joints; 

 leaves petiolate, hastate, cordate at base, acute, entire ; stipules nearly entire ; 

 flowers greenish-white, sometimes tinged with purple, pedicellate, in clusters of 

 8 t, nodding in fruit, forming small, interrupted racemes; outer calyx-lobes 

 carinate ; stamens 8 ; stylos 3 ; fruit mostly smooth, triangular. A homely 

 weed in cultivated grounds. Stem 1 5 ft. long. June Sept. An. 



14. P. cilinode. 



Fringed Bindweed. 



Slightly pubescent ; stems climbing and twining ; leaves somewhat hastate, 

 cordate at base, acuminate ; stipules fringed at base with reflexed hairs ; flowers 

 greenish-white, in panicled racemes; calyx-lobes scarcely carinate ; fruit smooth 

 and shining, triangular. A climbing species, distinguished by the fringed joint? 

 Stems 310 ft, long. Thickets and rocky hills. July Sept. An. 



15. P. Fagopyrum. 



Buckwheat. 



Smooth ; stem erect, branching; leaves sagittate or hastate, cordate at hasp 

 generally approaching to triangular in outline; stipules semi-cylindrical; flow- 

 ers white, often greenish or tinged with rose-color, in corymbose racemes, 01 

 panicles; stamens 8; styles 3; fruit longer than the calyx. A very common 

 grain, which remains in fields as a weed, where it has been cultivated. Th& 

 flowers are furnished with 8 yellow nectaries alternating with the stamens, 

 which are very attractive to the bees. Stem 2 ft. high. An. 



3. EtJMEX. 



Calyx persistent. Sepals 6 ; 3 outer united at base, spreading 

 in fruit ; 3 inner often bearing granules. Stamens 6. Styles 3. 

 Stigmas many-cleft, forming a tuft. Achenium 3-angled, covered 

 by the converging, valve-like, inner sepals. 



* Flowers mostly per feet ; some or all of the inner sepals 'bearing granules. 

 t Leaves lanceolate, acute at both end*. 



1. R. verticillatus. 



Swamp Dock. 



Stem erect, sparingly branched above; leaves oblong-lanceolate, flat, entire, 

 acute, pale green, long and narrow ; flowers in crowded whorls, forming long, 

 nearly leafless racemes ; pedicels dilated above, reflexed in fruit, several times 

 longer than the calyx valves, strongly reticulate, somewhat obtuse, all bearing 

 large granules. An aquatic species, most common in the northern districts of 

 N. Eng. and N. York, distinguished by its long, narrow leaves, and almost leaf- 

 less racemes. Stem 23 ft high. Muddy grounds. June. Per. 



2. R. Hydrolapathuin. Great Water-Dock. 



Stem tall, stout, branching; leaves oblong-lanceolate, acute, wavy on the 

 margin, on flat petioles; flowers greenish, on capillary pedicels, nodding, in 

 whorls, forming upright racemes, the whole combined in a large, compound, 

 terminal, and nearly leafless panicle ; calyx-valves ovate, obtuse, all bearing 

 granules. A stout aquatic species, 50 ft. high, in wet places, and, like tho 



