Entry From
Flora of North America, Vol 5,
Names
Rumex [family POLYGONACEAE], Sp. Pl., 1: 333. 1753 Gen. Pl. ed., 5, 156. 1754
Information
Herbs, perennial, biennial, or annual, synoecious (subg. Rumex and Platypodium) or dioecious (subg. Acetosa and Acetosella), occasionally polygamomonoecious, with taproots and usually short caudex, or sometimes rhizomatous and/or stoloniferous. Stems erect, ascending, or prostrate, glabrous or papillose-pubescent. Leaves basal (in some species) and cauline, alternate, petiolate; ocrea persistent or partially deciduous, membranous; petioles present on basal and proximal cauline leaves, absent on distal cauline leaves, bases not articulated; blades variable in shape, basal (if present) and proximal cauline leaves from broadly ovate or almost orbiculate to linear, becoming progressively smaller and narrower distally, margins entire (or basally lobate), flat, or occasionally undulate or crisped. Inflorescences terminal, sometimes terminal and axillary, paniclelike, rarely simple. Pedicels present. Flowers bisexual or unisexual, (1–)4–30 per ocreate fascicle, base stipelike; perianth green, pinkish, or red, campanulate, glabrous; tepals (5–)6, connate proximally, sepaloid, dimorphic, outer 3 remaining small, inner 3 usually enlarging, sometimes 1–3 with central vein transformed into tuberculate callosity (tubercle); stamens 6; filaments distinct, free, glabrous; anthers, yellow to brownish yellow, ovate to elongate; styles 3, spreading or reflexed, distinct; stigmas 3, fimbriate or plumose. Achenes included in accrescent and usually veiny perianth, tan to dark brown, unwinged to weakly winged, 3-gonous, sometimes compressed-3-gonous or nearly pyramidal, glabrous. Seeds: embryo straight. x = 7, 8, 9, 10 (polyploidy widespread in the genus).
Discussion
Carefully collected mature specimens with well-developed inner tepals are desirable for reliable identification of Rumex species. Vegetative characters (in particular, growth habit, basal and proximal cauline leaves, and inflorescences) also are crucial.
In Rumex the distal part of a functional pedicel (below the articulation with a true pedicel) is formed by the narrowed connate basal parts of the outer tepals (also known as a stipelike hypanthium base or pseudopedicel). However, for simplification of the keys and descriptions, the whole functional pedicel (including pseudopedicel) is referred to simply as pedicel.
The genus Rumex in the broad sense may be divided into at least four segregate genera: Rumex in the narrow sense, Acetosa, Acetosella, and Bucephalophora (see e.g., Á. Löve 1983; Löve and B. M. Kapoor 1967; N. N. Tzvelev 1987b, 1989b). These taxa probably represent distinct phylogenetic lineages; they have, however, not been generally accepted as separate genera by most taxonomists, including K. H. Rechinger (1937, 1949), monographer of Rumex in the broad sense. Moreover, in some cases they are connected by intermediate forms (especially Acetosa and Acetosella) and evidently are more closely related to each other than to any outgroup genus. In my opinion, this favors the retention of Rumex in the traditional broad sense, which is also nomenclaturally convenient.
Many Old World species of Rumex may be divided in their native areas of distribution into quite distinct subspecies or varieties. However, the same species occurring in North America as introduced aliens often are represented by atypical, intermediate specimens or even populations (as is true also for many native North American taxa occurring as aliens in Europe), which in many cases obscures those taxonomic distinctions.
Rumex rugosus Campderá, a commonly cultivated European species, was reported for North America by Á. Löve and D. Löve (1957) as a cultivated and occasionally escaped garden plant “in a few places in eastern Canada.” No specimens from escaped plants in the flora area have been seen.
![Rumex [family POLYGONACEAE]](/fsi/img/misc/plants/static_thumbs/flora_north_america_icon96.jpg)