酸模

Rumex acetosa is morphologically uniform in North America. It sometimes is misidentified as R. hastatulus orR. acetosella. Collections from North America are few in herbaria, and this species probably is not as common in the flora area as has been generally assumed. Some literature reports for R. acetosa may refer to other taxa of the species group.

Plants perennial, glabrous or nearly so, with short and relatively thin, horizontal or slightly oblique rootstock (usually not reaching deep into substrate) and ± crowded 2d-order roots. Stems erect or rarely ascending, 1 to several from base, branched in distal 2 (in inflorescence), (25-)30-90(-110) cm. Leaves: ocrea normally laciniate; blade oblong-ovate, ovate-lanceolate, to lanceolate, 4-10(-15) × 1-4(-6) cm, normally more than 2.5 times as long as wide, base sagittate (with acute lobes directed downward, ± parallel to petiole), margins entire, normally flat, apex acute or subacute. Inflorescences terminal, occupying distal 3 of stem, usually lax and interrupted especially in proximal part, narrowly paniculate, cylindric (with 1st-order branches simple, or with few 2d-order branches). Pedicels articulated near middle, filiform, 2-5(-6) mm, articulation distinct. Flowers (2-)4-8(-10) in whorls; inner tepals orbiculate, occasionally broadly ovate, 3-4(-5) × 3-4 mm, base rounded or cordate, apex obtuse; tubercles small or occasionally absent. Achenes black to dark brown, 1.8-2.5 × 1.2-1.5 mm, shiny, smooth. 2n = 14 (pistillate plants), 15 (staminate plants).

Herbs perennial, dioecious, with a short and relatively thin horizontal or slightly oblique rootstock, usually not reaching deep into substrate and with rather crowded secondary roots. Stems erect, 40-100 cm tall, grooved, glabrous, usually simple. Basal leaves ovate-lanceolate to lanceolate, base sagittate, 3-12 × 2-4 cm, margin entire, apex acute, basal lobes acute at apices; cauline leaves small; petiole short or nearly absent; ocrea fugacious, white, membranous. Inflorescence terminal, paniculate, lax; branches reddish green, slender, simple or with a few secondary branches. Flowers unisexual. Pedicel slender, articulate at middle. Male flowers: outer tepals erect, small; inner tepals elliptic, ca. 3 mm. Female flowers: outer tepals elliptic, reflexed in fruit; inner tepals enlarged in fruit; valves nearly orbicular (to broadly ovate), 3.5-4 mm in diam., with small recurved tubercles at base of valves, net veined, base cordate, margin entire, apex obtuse. Achenes blackish brown, shiny, ellipsoid, trigonous, ca. 2 mm. Fl. May-Jul, fr. Jun-Aug. 2n = 14*, 15*, 22*.

Perennial. Stem erect, up to 120 cm high, leafy. Leaves hastate of variable size; basal leaves 2-4 times as long as broad, oblong-elliptic, with acute basal downwards directed lobes and long petioles; stem leaves upwards gradualy smaller and with shroter petioles, the uppermost sessile with clasping basal lobes. Taste of leaves sour. Panicle narrow, loose with non fasciculate simple or little divided branches. Flowers dioecious, arranged in few flowerd whorls. External perianth segments reflexed, appressed to the articulate pedicel. Valves suborbicular, 3-3.5 mm in diam., membranous, finely reticulate, with a small basal reflexed grain. Nut 1.8-2.2 mm long, dark brown.

Europe, W. Asia, Himalaya (Kashmir to Nepal), Tibet, Siberia, China, Japan, N. America.

introduced; St. Pierre and Miquelon; Alta., B.C., Man., N.B., Nfld. and Labr. (Nfld)., N.S., Ont., Que., Sask.; Alaska, Conn., Maine., Mass., Mich., Minn., N.H., N.Y., Oreg., Pa., Vt.; Europe; nw Africa; Asia.

?Anhui, ?Fujian, ?Guangxi, ?Guizhou, Heilongjiang, ?Henan, Hubei, ?Hunan, Jiangsu, Jilin, Liaoning, Nei Mongol, Qinghai, ?Shaanxi, ?Shandong, ?Shanxi, Sichuan, Taiwan, Xinjiang, Xizang, Yunnan, ?Zhejiang [Japan, Kazakhstan, Korea, Kyrgyzstan, Mongolia, Russia; Europe, North America].

Distribution: Europe except the Mediterranean, subarctic and temperate Asia, in the South at high elevation only, North America, Greenland. Occasionally as an alien elsewhere.

2100-4100 m

Fl. Per.: July-September.

Flowering spring-early summer.

Waste places, meadows, cultivated fields, alluvial habitats; 0-1000m.

Mountain slopes, forest margins, moist valleys; 400-4100 m.

A fairly common species of moist areas especially on slopes and moist rocks, grows on higher altitudes between 2000-4500 m. Resembles with Rumex hastatus but differs by having herbaceous habit, small panicle and less freely branched stem.

Acetosa pratensis Miller; Rumex acetosa subsp. pratensis (Miller) A. Blytt & O. C. Dahl

Acetosa pratensis Miller.