Suaeda
Onomat. Bot. Compl. 8: 797. 1776.
Herbs, subshrubs, or shrubs [trees], annual or perennial, glabrous or pubescent, glaucous or not. Stems prostrate to erect, simple or branched, not jointed, not armed, not fleshy. Leaves alternate or opposite, sessile or short-petiolate, fleshy; blade glaucous or green, linear, lanceolate, oblanceolate, or elliptic, flat or semiterete to terete, base usually narrowed, margins entire, apex blunt or rounded to acute or apiculate. Inflorescences dichasial cymes, forming glomes (clusters of flowers) of 1–12 flowers, usually arrayed in compound spikes or sometimes racemes; each glome in axis of one leaflike bract, on branchlet fused to one leaflike bract, or bractless, subtended by 1–7 bracteoles; bracteoles persistent, ovate to lanceolate, 0–1.5 mm, membranous, margins entire or laciniate, sometimes ciliate, apex rounded or acute to acuminate. Flowers all bisexual or bisexual and pistillate intermixed, staminate flowers sometimes present; perianth actinomorphic, zygomorphic, or irregular; perianth segments persistent and enclosing fruit, 5, distinct or proximally to almost completely connate, usually succulent, sometimes thin, margins ± scarious; stamens [1–](2–)5; anthers exserted (or included); stigmas 2–5. Fruits utricles, shape variable, determined by seed shape; pericarp waxy, becoming membranous and ± separable from seeds at maturity. Seeds horizontal or vertical, sometimes dimorphic, subglobose or lenticular to flattened; seed coat black, blackish brown, blackish red, or brownish green, smooth or papillate to reticulate; embryo coiled; perisperm absent or scant. x = 9.
Distribution
Worldwide.
Discussion
Species ca. 110 (12 in the flora).
Plants of Suaeda are found in saline or alkaline wetlands or, occasionally, in upland habitats. Some species are cultivated and eaten as a vegetable; seeds of some have been ground and eaten by Native Americans, and some species are used as a source for red or black dye.
The genus Suaeda includes widely distributed polymorphic species such as S. maritima, S. calceoliformis, and S. nigra. Much of the variation in these taxa appears to be due to environmental factors, but some of it is probably due to genetic differences. Infraspecific taxa and presumed related species have been described, and these are mentioned in the discussions following the descriptions. However, no infraspecific taxa are recognized here. All three of these species show much variation in morphology and growth-form characteristics, but no qualitative characters could be found that could be used to reliably separate distinct taxa below the species level. Future chromosomal and genetic studies may enable the recognition of distinct infraspecific taxa or even species within these three polymorphic entities.
Identification of Suaeda specimens is achieved most successfully when based upon material containing flowers (for ovary shape) and mature calyces (for lobe shape) containing seeds. Because of the succulent nature of most specimens, fresh material may appear quite different than dried material, especially in the accentuation of calyx features when dry.
Selected References
Key
Key to Sections
| 1 | Glomes on branchlets partially fused to bracts | Suaeda sect. Schanginia |
| 1 | Glomes axillary to bract or bractless, not on branchlets partially fused to bracts | > 2 |
| 2 | Herbs annual, suffrutescent perennials, or subshrubs, glabrous; perianths irregular or zygomorphic, sometimes appearing ± actinomorphic; perianth segments abaxially ± flat or rounded (convex), sometimes distally hooded, and/or with abaxial appendages (transverse proximal wings, keels, and/or distal horns); stigmas on attenuated apex of ovary, not arising from pit; cross sections of fresh leaves ± uniformly green (best seen at 10× or greater magnification) | Suaeda sect. Brezia |
| 2 | Shrubs, subshrubs, or sometimes facultative annuals, pubescent or glabrous; perianths actinomorphic; perianth segments abaxially rounded (convex), sometimes distally hooded, but without appendages; stigmas arising from pit at apex of ovary or from pit on distal necklike extension of ovary; cross sections of fresh leaves with dark-green ring of chlorenchyma just inside epidermis (best seen at 10× or greater magnification) | Suaeda sect. Limbogermen |