BUCKWHEAT FAMILY. POLYGONACEAE.

Fig 31. [Knot-Grass. Polygonum aviculare] L.

Knot-Grass. Polygonum aviculare L. This door-yard weed is in no sense a grass. Achenes unequally 3-sided, ovoid, acute, angles obtuse, surface, dull, light to dark reddish brown, finely granular and striate lengthwise. 1.8–2.2 mm. long, usually with the remains of calyx attached. Native of this country. Common about door-yards.

Fig 32. [Wild Buckwheat. Polygonum Convolvulus] L.

Wild Buckwheat. Polygonum Convolvulus L. Achenes dull, jet-black, equally 3-sided, elliptical to obovoid, minutely granular often with faint longitudinal striation, the faces often more or less concave, the angles rounded, 2.5–3.5 mm. long, sometimes with the remains of calyx attached. Introduced from Europe. Often climbing up corn stalks.

Fig 33. [Erect Knotweed. Polygonum erectum] L.

Erect Knotweed. Polygonum erectum L. Achenes dull, light to dark brown, unequally 3-sided, ovoid or rhombic, finely granular and striate lengthwise, the faces sometimes concave, the angles rounded, 2.5–3 mm. long, sometimes with the remains of calyx attached. Native to this country. Of little account.

Fig 34. [Smart-weed. Polygonum Hydropiper] L.

Smart-weed. Polygonum Hydropiper L. Achene dull, granular, light to dark reddish brown, lenticular, acutely and narrowly or broadly elliptical, or 3-sided, apex acute, concave on the sides, angles obtuse, 2–3 mm. long, sometimes with the remains of the dotted calyx attached. Introduced from Europe. Wet land.

Fig 35. [Dock-leaved or Pale Persicaria. Polygonum lapathifolium] L.

Dock-leaved or Pale Persicaria. Polygonum lapathifolium L. Achene shining, dark to chestnut brown, 2–2.2 mm. long, flattened, circular to broadly ovate with abruptly pointed apex, the base obtuse or bearing the remains of the thin calyx. Introduced from Europe. Low wet places.

Shore Knotweed. Polygonum littorale Link. So far as the achenes are concerned, they are identical with those of P. aviculare above described. Native of this country. On hard or thin places, especially when newly graded.

Fig 36. [Pennsylvania Persicaria, Polygonum Pennsylvanicum] L.

Pennsylvania Persicaria, Polygonum Pennsylvanicum L. Achene shining, jet-black, flattened, surface very slightly uneven and granular nearly circular with a short abrupt apex, edge rounded, 2.5–3 mm. long, often bearing the remains of the calyx. Native to this country. Occasional in annual crops.

Fig 37. [Lady's Thumb. Polygonum Persicaria] L.

Lady's Thumb. Polygonum Persicaria L. Achene shining, jet-black, surface finely uneven, much flattened with rounded edges or with 3 nearly equal concave faces, the edges faintly angled along the center, broadly ovate, base obtuse or bearing a portion of the calyx, apex abruptly pointed, 2–2.3 long. Introduced from Europe. Waste places and stubble ground.

Fig 38. [Climbing False Buckwheat. Polygonum scandens] L.

Climbing False Buckwheat. Polygonum scandens L. Achene black, shining, in cross-section sides flat or concave, corners rounded, obovate, in vertical outline sides rounded to an obtuse apex, from rounded sides to base slightly concave, base acute, 3.5–4 mm. long when freed from the persistent base of the calyx. Woods and shady places. Not prominent as a weed.

Fig 39. [Sorrel. Sour Dock. Rumex Acetosa] L.

Sorrel. Sour Dock. Rumex Acetosa L. Calyx-wings broadly ovate or orbicular, heart-shaped 3.5–4.5 mm. long, achene shining, with 3 equal sides, broadly oval, both ends abruptly pointed, the thin edges usually lighter colored than the dark brown or black convex faces, 1.5–2 mm. long. Introduced from Europe. Not common.

Fig 40.[Sheep Sorrel. Rumex Acetosella] L.

Sheep Sorrel. Rumex Acetosella L. Achenes usually closely covered by dull reddish brown, finally roughened calyx, which is removed with difficulty; achenes shining with 3 equal sides, broadly oval, the base rounded, the apex abruptly pointed, sides convex, reddish brown or amber color, corners obtuse, darker colored. Native of this country, though in large part introduced from Europe. Very common in thin sandy meadows.

Fig 41. [Narrow-leaved or Curled Dock. Rumex crispus] L.

Narrow-leaved or Curled Dock. Rumex crispus L. Achene covered by 3 brown heart-shaped calyx-wings, which are 2.5–3.5 mm. long, each bearing an ovoid, acute tubercle; one of them is 1.5 mm. long, the other two smaller. Achene ovoid, 3-angled, shining, rich reddish-brown, 1.3–1.8 mm. long, .7–1.4 mm. wide, in transverse section the angles prominent, convex sides and angles concave near the base; base abruptly acute; when viewed vertically sides and angles concave near the apex; apex abruptly acute, compare these notes with those concerning R. obtusifolius. Introduced from Europe. Very common on low land and in meadows.

Fig 42. [Broad-leaved or Bitter Dock. Rumex obtusifolius] L.

Broad-leaved or Bitter Dock. Rumex obtusifolius L. Achene covered by three brown, hastate-deltoid calyx-wings, which are about 4 mm. long, each bearing an ovoid-elliptical tubercle, one of them 1.5 mm. long, the other two very narrow, rudimentary. Achenes ovoid, 3-angled, less polished than those of R. crispus, light brown, 2–2.4 mm. long, 1–1.4 mm. wide, angles in transverse section slight, sides convex, usually in a greater degree than in the specie just named, vertically sides and angles very slightly concave or straight near the base which is abruptly acute; sides and angles near the apex scarcely concave or straight; apex acute. Introduced from Europe. Not very common.

Fig 43. [Patience Dock. Rumex Patientia] L.

Patience Dock. Rumex Patientia L. Calyx-wings circular-heart shaped, 4–6 mm. long, one of them bearing a prominent ovoid tubercle; achene ovoid-elliptical, 3-angled, somewhat polished, shining, light-brown, 2.5–3.5 mm. long, 1.7–2 mm. wide, angles prominent, sides straight, in transverse section, not counting the angles, base rounded, not counting the abrupt point, when seen vertically, the sides near the apex are straight or slightly concave. Introduced from Europe. Not common.

Fig 44. [Willow-leaved Dock. Rumex Mexicanus] Meisn. Rumex salicifolius Weinm.

Willow-leaved Dock. Rumex Mexicanus Meisn. Rumex salicifolius Weinm. Calyx-wings triangular-ovate, about 3 mm. long, each bearing a large tubercle; achene dark reddish brown, smooth, shining, 1.8–2.2 mm. long, ovoid, angles prominent, the sides viewed transversely rounded, the sides of the base as viewed vertically, rounded, straight or slightly concave, near the apex straight or concave. A native of Northeastern North America. Not common.