FNA: Dysphania vs. Chenopodiaceae

Distribution

Worldwide; mostly tropics; subtropics; warm-temperate zones

Worldwide; especially in desert and semidesert regions; often in alkaline or saline habitats

Discussion

Species ca. 32 (10 in the flora).

The generic name Dysphania traditionally was applied to seven to ten species endemic to Australia (P. Aellen 1930, 1930b; A. J. Scott 1978b; P. G. Wilson 1983, 1984, 1987). Placement and rank of this taxon have ranged from a mere section in Chenopodium (P. Aellen 1930, 1930b) to the sole genus of a separate family Dysphaniaceae, or a representative of Illicebraceae. Dysphania’s close affinity to “glandular” species of Chenopodium sensu lato is now evident (P. Aellen 1930, 1933, 1960–1961; T. Eckardt 1964b, 1967, 1967b, 1968, [1969]; T. J. Mabry and H.-D. Behnke 1976; F. A. Pax and K. Hoffmann 1934b; A. J. Scott 1978b; P. G. Wilson 1983, 1984, 1987).

Here the genus Dysphania is accepted in an expanded circumscription (S. L. Mosyakin and S. E. Clemants 2002), including all other “glandular” taxa previously treated in Chenopodium subg. Ambrosia A. J. Scott, or segregated in genera such as Roubieva Moquin-Tandon, Teloxys Moquin-Tandon, and Neobotrydium Moldenke. In its traditional circumscription Dysphania has no distinctive characters clearly separating it from those other “glandular” chenopods.

Presence of glandular trichomes seems to be a character of high phylogenetic and taxonomic importance in Chenopodiaceae, in which types of trichomes were used for delimitation of genera, tribes, and even subfamilies. This character seldom fails, even if there are some parallel evolutionary trends present. R. C. Carolin (1983) suggested that Chenopodieae with glandular hairs probably separated from Chenopodieae with bladder hairs even at a more basal (earlier) phylogenetic level than the point of divergence of the latter from Atriplicinae. Chenopodium species with bladder hairs (“mealy chenopods”) are probably more closely related to Atriplex and its satellite genera than to “glandular chenopods.” P. G. Wilson (1984, 1987) came to the same conclusion.

W. A. Weber (1985) adopted the name Teloxys Moquin-Tandon for the group of “glandular” taxa and transferred several species of “glandular” Chenopodium to Teloxys. The latter was published simultaneously with Roubieva, and thus, if only these two generic names are considered, Weber’s choice should stand. However, the generic name Dysphania predates both Teloxys and Roubieva, and “...[I]f Teloxys, Orthosporum, and Dysphania are amalgamated then the oldest name Dysphania should be adopted” (P. G. Wilson 1987).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Genera ca. 100, species ca. 1500 (27 genera, 168 species in the flora).

A number of species introduced from Europe and Asia are weedy in North America. The widespread distribution of the family in the deserts of Eurasia and Australia is indicative of the ancient status of the family. Fossil pollen from this family dates to the Maestrichtian, providing the oldest known fossils in the Caryophylliidae.

Plants in this family typically have Crassulacean Acid Metabolism, have either a C3 or C4 photosynthetic pathway (W. V. Brown 1975; G. W. Welkie and M. Caldwell 1970), accumulate organic acids, free nitrates, and oxalates, and often contain alkaloids. Along with other members of the Caryophyllales, members of the family contain pigments called betalains (named for the genus Beta) rather than anthocyanins.

Economically important members of this family include spinach and chard (Spinacia oleracea) and beets (Beta vulgaris). Seeds in this family generally provide a rich source of protein, and one species, Chenopodium quinoa, is gaining widespread acceptance as a cereal crop. Toxicity from high levels of nitrates or oxalates has been reported for a number of species (J. M. Kingsbury 1964), and the pollen is known to be allergenic (T. C. Fuller and E. McClintock 1986). The nutritional characteristics of many species that we share with northern Asia were described by M. M. Iljin (1936).

Molecular and morphologic studies provide evidence supporting the inclusion of the Chenopodiaceae within Amaranthaceae (Angiosperm Phylogeny Group 1998; W. S. Judd and I. K. Ferguson 1999; J. E. Rodman 1990). However, until discordant elements within these lineages, such as Sarcobatus (H.-D. Behnke 1997), are interpreted within a larger evolutionary scheme, the disposition of family groups remains problematic.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Key

Key to the Sections and Subsections of Dysphania

1. Seeds vertical	sect. Orthospora
1. Seeds mostly horizontal (sometimes vertical in sect. Adenois)	→ 2
2. Flowers in dense glomerules arranged in spicate or paniculate inflorescences	sect. Adenois
2. Flowers solitary or in few-flowered glomerules arranged in lax cymose inflorescences [6b. Dysphania sect. Botryoides]	→ 3
3. Leaf blades linear, narrowly lanceolate, or narrowly oblanceolate, margins unlobed; terminal branches of inflorescence usually bristle-tipped	subsect. Teloxys
3. Leaf blades lanceolate to ovate or elliptic, margins lyrate-sinuate or pinnatifid (rarely unlobed); terminal branches of inflorescence usually ending in glomerules	→ 4
4. Perianth segments not tuberculate	subsect. Botrys
4. Perianth segments often with single subterminal tubercle.	subsect. Incisa

Key to the Species of Dysphania

1. Seeds vertical	→ 2
1. Seeds mostly horizontal (vertical in D. chilensis, sometimes vertical in D. ambrosioides and D. anthelmintica)	→ 5
2. Perianth urceolate, perianth segments connate almost to top, enclosing fruit; leaf blades with margins deeply pinnatifid to pinnatisect	D. multifida
2. Perianth segments connate well below middle, hardly enclosing fruit; leaf blades with margins coarsely sinuate-dentate with obtuse lobes [6c. Dysphania sect. Orthospora]	→ 3
3. Perianth segments rounded abaxially	D. pumilio
3. Perianth segments keeled or crested	→ 4
4. Perianth segments keeled, not crested; leaf blades ovate	D. carinata
4. Perianth segments keeled and crested; leaf blades elliptic or ovate	D. cristata
5. Flowers in dense glomerules arranged in spikes or panicles [6a. Dysphania sect. Adenois]	→ 6
5. Flowers solitary or in few-flowered glomerules arranged in lax cymose inflorescences [6b. Dysphania sect. Botryoides]	→ 8
6. Inflorescences leafless (glomerules without subtending leaves throughout inflores- cence, or subtending leaves very small, shorter than glomerules)	D. anthelmintica
6. Inflorescences foliose to top (glomerules with reduced leaflike bracts)	→ 7
7. Leaf blades mostly ovate, oblong-lanceolate, or lanceolate, margins entire, den- tate, or laciniate, usually copiously gland-dotted but not villous	D. ambrosioides
7. Leaf blades lanceolate, margins shallowly dentate to sinuate-pinnatifid, villous and gland-dotted	D. chilensis
8. Leaf blades linear, narrowly lanceolate, or narrowly oblanceolate, margins unlobed; terminal branches of inflorescence usually bristle-tipped [6b.3. Dysphania subsect. Teloxys]	D. aristata
8. Leaf blades lanceolate to ovate or elliptic, margins lyrate-sinuate or pinnatifid (rarely unlobed); terminal branches of inflorescence usually ending in glomerules	→ 9
9. Perianth segments not tuberculate [6b.1. Dysphania subsect. Botrys]	D. botrys
9. Perianth segments with single subterminal tubercle [6b.2 Dysphania subsect. Incisa]	D. graveolens

1. Leaves scalelike; stems fleshy or succulent; plants of saline habitats	→ 2
1. Leaves well developed, not scalelike; stems not fleshy (except Arthrocnemum, and Sarcocornia, which is fleshy when young); plants of various habitats	→ 5
2. Leaves alternate	Allenrolfea
2. Leaves opposite	→ 3
3. Plants annual herbs; all stems terminated by an inflorescence	Salicornia
3. Plants perennial shrubs; many stems entirely vegetative	→ 4
4. Flowers distinct in each cyme, not adnate; outer seed coat hard, tuberculate	Arthrocnemum
4. Flowers of each cyme adnate to distal branch of inflorescence; outer seed coat thin, covered with hooked or straight hairs	Sarcocornia
5. Leaves opposite; perianth strongly imbricate	Nitrophila
5. Leaves alternate, rarely opposite; perianth slightly, if at all imbricate	→ 6
6. Inflorescence leaves or bracts tipped with spine or spinelike bristle	→ 7
6. Inflorescence leaves and bracts not tipped with spine or bristle	→ 9
7. Leaves triquetrous, triangular in cross section, terminating in soft or rarely rigid, flattened bristle	Polycnemum
7. Leaves terete or flat in cross section, terminating in stiff, mucronate spine tips or bristle	→ 8
8. Fruiting perianth abaxially winged; leaves linear to subulate, herbaceous or fleshy, spine-tipped or not; bracts of inflorescence ovate-lanceolate, spine tipped	Salsola
8. Fruiting perianth apically winged; leaves terete, fleshy-succulent, bristle- tipped; bracts of inflorescence similar to leaves	Halogeton
9. Leaves sub- or semicylindric to linear, usually fleshy	→ 10
9. Leaves with flattened blades, not especially fleshy	→ 12
10. Shrubs armed with thorny branches; flowers unisexual, staminate flowers in spikes, pistillate flowers solitary or paired and axillary	Sarcobatus
10. Shrubs or herbs, not armed; flowers bisexual or both bisexual and pistillate, solitary or 2-5 in axillary clusters	→ 11
11. Fruiting perianth developing horizontal, membranceous wings or tubercles; leaves herbaceous	Kochia
11. Fruiting perianth without wings or tubercules, unchanged from flowering peri- anth; leaves fleshy	Suaeda
12. Plants stellate-pubescent annual herbs	Axyris
12. Plants glabrous, farinose, or with dendritic hairs; if the latter, then plants woody perennials	→ 13
13. Plants densely tomentose with at least some stellate hairs becoming golden brown in age, subshrubs	Krascheninnikovia
13. Plants hairy or glabrous, not as above, shrubs or herbs	→ 14
14. Pistillate flowers usually lacking perianth, at least some flowers enclosed by 2 accrescent or connate bracts in fruit; flowers unisexual or, rarely, bisexual	→ 15
14. Perianth present, not enclosed by paired bracts in fruit; flowers bisexual or unisexual (Micromonolepis) or some also pistillate	→ 19
15. Stigmas 4 or 5; plants cultivated herbs	Spinacia
15. Stigmas 2; plants not or seldom cultivated	→ 16
16. Bracts (or bractlike perianth segments) dorsally compressed, usually triangular, smooth, tuberculate, vertically keeled, or winged; pubescence usually of inflated hairs or, sometimes, none; axillary rounded buds absent or inconspicuous	→ 17
16. Bracts laterally compressed, keeled, or winged, lacking appendages; pubescence of simple or branched hairs	→ 18
17. Bractlike perianth segments united below middle, vertically keeled; plants annual	Suckleya
17. Bracts united above middle, not vertically keeled; plants pe- rennial or annual	Atriplex
18. Shrubs with divaricate, often spinescent branches; bracts with margins thickened, spongy within; pubescence of branched hairs	Grayia
18. Shrubs with erect thornless branches; bracts with margins not spongy-thickened, either obcompressed or dorsiventrally compressed and 6-ribbed; pubescence of scurfy or moniliform hairs	Zuckia
19. Perianth horizontally winged in fruit	→ 20
19. Perianth not horizontally winged in fruit	→ 21
20. Leaf blade margins sinuate-dentate; plants ± villous or tomentulose, becoming glabrous with maturity	Cycloloma
20. Leaf blade margins entire; plants usually glabrous, sometimes slightly pubescent	Kochia
21. Proximal leaves petiolate, middle ones merely sessile, distal ones cordate-clasping; style branches 3	Aphanisma
21. Leaves not as above; style branches mainly 2	→ 22
22. Perianth segments each armed with spiniform, hooked, or conic appendages	Bassia
22. Perianth segments rounded or keeled abaxially, lacking wings or spines	→ 23
23. Ovary partly inferior; plants cultivated, rarely naturalized	Beta
23. Ovary superior; plants native or naturalized, not cultivated	→ 24
24. Perianth lobes 5, largely enfolding and concealing to exposing fruits; stamens usually 5	→ 25
24. Perianth lobes 1-3 or absent; fruits largely exposed; stamens 1-3(-5)	→ 26
25. Plants (at least some parts) with glandular or glandular-vesicular hairs	Dysphania
25. Plants farinose or glabrous	Chenopodium
26. Plants dichotomously branched, ultimate branches filiform; leaves oblong, succulent	Micromonolepis
26. Plants not dichotomously branching, ultimate branches not filiform; leaves triangular-lanceolate to oblanceolate, spatulate, or linear	→ 27
27. Leaves triangular-lanceolate to oblanceolate or spatulate; perianth segments usually 1 (2-3 segments in central flowers); stamens usually 1; plants widespread, of many habitats	Monolepis
27. Leaves lanceolate, linear-lanceolate, or filiform; perianth segments 1-3; stamens 1-3(-5); plants of sandy, low elevation sites.	Corispermum