- Family: Dock Family – Polygonaceae
- Growing form: Perennial herb.
- Height: 60–150 cm (25–60 in.). Stem green when young, later reddish, grooved, branching from inflorescence.
- Flower: Regular (actinomorphic), bisexual, up to 10 mm (0.4 in.) wide. Perianth-segments in two whorls of three. Segments of outer whorl small and spreading–obliquely forward-pointing. Inner whorl forms fruit valves, which are widely ovately triangular. Stamens 6. Pistil of 3 fused carpels, styles 3. Joint on flower-stalk (5–10 mm (0.2–0.4 in.)) near base. Inflorescence a whorled, quite short compound raceme, initially pale green, later dark brown.
- Leaves: Spirally. Lower leaves with cordate base, broadly ovate–triangular, long-stalked, somewhat crinkled, veined along papillae. Stem leaves ovate.
- Fruit: Achene 3–4 mm (0.12–0.16 in.), brown. Perianth segment lobes quite round, with cordate base, clearly veined, with rounded teeth (crenate), 6–10 mm (0.24–0.4 in.) long, at least one (often two) with quite small, long tubercle. Fruit-stalk 3–10 mm (0.12–0.4 in.), about same length as calyx. Basal part of node quite thick.
- Habitat: Culturally-influenced land, railway yards, waste ground, harbours, sea shores.
- Flowering time: July.
Genus Rumex is comprised of some 200 species wordwide, of which approx. 20 grow in Finland. They are quite a troublesome group because members easily cross-breed – Asiatic dock especially with northern dock (R. longifolius) and curled dock (R. crispus). The calyx of the ripe fruit is helpful (and often necessary) to identify the plant. Asiatic dock is quite a ’new’ established alien in Finland, and it can be found in old garrison areas such as Suomenlinna next to Helsinki in southern Finland.
Triangular-valved doc & Marsh dock
Rumex triangulivalvis & Rumex palustris
Other new arrivals or otherwise rare members of genus Rumex in Finland are triangular-valved dock, marsh dock, monk’s rhubarb (R. alpinus), tropical dock (R. obovatus), toothed dock (R. dentatus) and golden dock (R. maritimus).
NOT TRANSLASTED YET. Meksikonhierakan lehdet ovat kapeansuikeita ja lähes poimuttomia. Hedelmissä on pitkä, selkeä nystermä ja hedelmäverhiöt ovat ehytlaitaisia. Mutahierakka viihtyy kosteilla paikoilla. Se on yläosasta haarova. Hedelmäverhiön liuskat ovat terävähampaisia (hampaita yleensä 3).