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Published In: Species Plantarum 1: 218. 1753. (1 May 1753) (Sp. Pl.) Name publication detailView in BotanicusView in Biodiversity Heritage Library
 

Project Name Data (Last Modified On 9/1/2009)
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4. Chenopodium L. (goosefoot, pigweed)

Plants usually annual (perennial elsewhere), the roots not tuberous-thickened. Stems prostrate to erect, not succulent, not appearing jointed, few- to much-branched, glabrous, glandular-hairy (sometimes also with nonglandular hairs), or sparsely to moderately mealy. Leaves alternate, well developed, not or only slightly succulent, petiolate or nearly sessile. Leaf blades linear to ovate or triangular, sometimes with a pair of spreading basal lobes, flattened in cross-section, not clasping the stem, rounded or narrowed to a sharply pointed tip, the margins entire, wavy, toothed, or lobed, the surfaces glabrous, glandular- and/or nonglandular-hairy, or sparsely to densely mealy. Inflorescences axillary and/or terminal, consisting of small flower clusters, these often appearing as interrupted spikes or panicles (occasionally a few nodes then with solitary flowers), the flowers not sunken into the axis. Flowers perfect (rarely a few pistillate flowers also present). Bracts absent or rarely 3 and minute. Calyx deeply 5-lobed, the lobes persistent at fruiting and all or partially enclosing the fruit, not winged, spaced evenly around the flower, often keeled or with a low, vertical ridge, rarely fleshy (in C. capitatum). Stamens 3–5 (usually only 1 in C. pumilio). Ovary superior. Styles 2 or 3, short, sometimes fused toward base, the stigmas 1 per style, linear or capitate. Fruits elliptic to circular in cross-section, depressed-globose to ovate in outline, somewhat flattened laterally or vertically, indehiscent or irregularly dehiscent, the wall thin and papery to membranous. Seed adhering loosely or tightly to the fruit wall, positioned vertically or horizontally, the surface smooth or less commonly roughened or with a low network of fine, rounded ridges, dark brown to black, shiny or less commonly dull, the coiled embryo usually apparent. About 150 species, nearly worldwide.

Immature specimens of Chenopodium often are difficult or impossible to identify and should not be collected. Fruits will, however, sometimes mature in the plant press while samples are drying. For large plants, it may be important to note the morphology of the larger, lower leaves when collecting samples for later determination. The adherence of the thin, membranous to papery wall of the fruit to the seed usually can be tested by rubbing a few mature fruits lightly between thumb and forefinger. In species with loosely adhering fruit walls this action will suffice to remove them, but in species with tightly adhering walls it will serve only to strip away the calyx.

Some species of Chenopodium, notably C. album, are cooked and eaten as a spinach substitute or (in combination with Amaranthus, Lactuca, Sonchus, Rumex, etc.) as field greens in the springtime when tender young growth is present (Steyermark, 1963). Native Americans also ground the seeds for flour (Moerman, 1998).

Crawford and Wilson (1986) included Missouri in their synopsis of the range of the western species C. atrovirens Rydb. However, in response to a query during the present research, Daniel J. Crawford (then of Ohio State University) indicated that this was a typographical error and was intended to read MT (Montana), rather than MO (Missouri).

Chenopodium bonus-henricus L. (good King Henry) is a perennial herb that is cultivated occasionally for its spinachlike leaves. It may be encountered in the future as an escape in Missouri. Aside from the thick, woody rootstock, this species may be recognized easily by the triangular leaves often with a pair of spreading basal lobes (similar in appearance to those of some Missouri species of Atriplex) and the oblong calyx lobes only partially enclosing the fruit, with the tips truncate to rounded or broadly angled and usually somewhat irregular margins.

 

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1 1. Plants with the leaves and/or calyx pubescent with glandular or nonglandular hairs, and/or with minute, sessile, yellowish resinous glands (these globose when fresh, often flattening when dried); plants often with a resinous or unpleasant odor

2 2. Leaves (except the uppermost) mostly more than 5 cm long, lacking hairs but with sparse to moderate sessile, yellowish resinous glands ... 2. C. AMBROSIOIDES

Chenopodium ambrosioides
3 2. Leaves (except the lowermost) mostly less than 4 cm long, lacking sessile glands but with moderate to dense, short glandular and/or nonglandular hairs

4 3. Calyces with short glandular hairs; well-developed inflorescences consisting of small axillary panicles; seeds mostly positioned horizontally, the surface roughened or finely wrinkled, often mottled ... 4. C. BOTRYS

Chenopodium botrys
5 3. Calyces with sessile glands and sometimes also short, nonglandular hairs; well-developed inflorescences consisting of short axillary spikes; seeds positioned vertically, the surface smooth ... 16. C. PUMILIO

Chenopodium pumilio
6 1. Plants with the leaves and/or calyx glabrous or sparsely to densely white-mealy (the mealy hairs more or less bladder-shaped when fresh, lozenge-shaped when dry); plants lacking a pronounced odor (except in the mealy C. watsonii and sometimes C. berlandieri)

7 4. Leaf blades entire; blades of main leaves linear to narrowly oblong, narrowly lanceolate, or less commonly narrowly ovate, mostly more than 3 times as long as wide

8 5. Leaf blades linear or very narrowly oblong, with only a single midvein and no other veins visible ... 14. C. PALLESCENS

Chenopodium pallescens
9 5. Leaf blades (except sometimes toward the branch tips) narrowly lanceolate to oblong-lanceolate, lanceolate, or less commonly narrowly ovate; venation more complex, with secondary veins branching from the main vein(s); if no secondary veins present, then the blades with 3 main veins from the base

10 6. Calyx only partially covering the fruit (the lobes extending past the widest part but not reaching the stylar area, leaving much of the portion above the rim exposed); calyx lobes flat or slightly rounded dorsally, not keeled ... 19. C. STANDLEYANUM

Chenopodium standleyanum
11 6. Calyx covering the fruit (the lobes extending to the stylar region or nearly so, obscuring all or nearly all of the fruit surface) (usually somewhat spreading in C. pratericola and then more or less exposing the fruit); calyx lobes keeled dorsally

12 7. Fruit wall membranous, smooth or often faintly granular, adhering relatively tightly to the seed; seed relatively strongly flattened horizontally, lens-shaped (narrowly biconvex) ... 1. C. ALBUM

Chenopodium album
13 7. Fruit wall membranous to somewhat papery, smooth, adhering loosely to the seed; seed only somewhat flattened horizontally, depressed-ovoid

14 8. Stems prostrate to loosely ascending; leaves mostly relatively thick and sometimes slightly fleshy, moderately to densely mealy on both surfaces; calyx lobes not or only slightly spreading at fruiting, covering the fruit ... 7. C. DESICCATUM

Chenopodium desiccatum
15 8. Stems erect or ascending; leaves relatively thin and herbaceous, moderately to densely mealy on the undersurface, glabrous or sparsely mealy on the upper surface; calyx lobes usually somewhat spreading at fruiting, exposing the tip of the fruit ... 15. C. PRATERICOLA

Chenopodium pratericola
16 4. At least a few of the leaf blades toothed or lobed; blades of main leaves variable but mostly triangular to rhombic-ovate, ovate, elliptic, or less commonly broadly lanceolate, mostly less than 3 times as long as wide

17 9. Calyx 3(5)-lobed; some or all of the seeds positioned vertically

18 10. Leaves densely white-mealy on the undersurface, glabrous or sparsely mealy on the upper surface ... 9. C. GLAUCUM

Chenopodium glaucum
19 10. Leaves glabrous on both surfaces, not mealy, green

20 11. Flower clusters relatively large, becoming 515 mm in diameter at fruiting, the calyx turning fleshy, red ... 6. C. CAPITATUM

Chenopodium capitatum
21 11. Flower clusters relatively small, becoming 35 mm in diameter at fruiting, the calyx remaining herbaceous to scalelike, green ... 17. C. RUBRUM

Chenopodium rubrum
22 9. Calyx (4)5-lobed; all of the seeds positioned horizontally

23 12. Plants short, bushy, the stems 525 cm long, much-branched from the base

24 13. Fruit wall appearing membranous and more or less transparent at maturity, easily separated from the seed; plants lacking an odor ... 10. C. INCANUM

Chenopodium incanum
25 13. Fruit wall appearing thicker and opaquely white at maturity, difficult to separate from the seed; plants with a pronounced unpleasant odor ... 22. C. WATSONII

Chenopodium watsonii
26 12. Plants taller, the stems to 200 cm long, if less than 25 cm long then with few to no branches

27 14. Fruits with the surface appearing honeycombed (often visible only with magnification), finely pitted, the pits usually more or less rectangular, separated by a network of thin ridges (do not confuse fruit wall with seed surface)

28 15. Largest leaves with the middle lobe elongate, appearing narrowly oblong, more or less parallel sided for most of its length ... 8. C. FICIFOLIUM

Chenopodium ficifolium
29 15. Largest leaves with the middle lobe not elongate, appearing ovate to triangular, angled or tapered from near the base

30 16. Calyx lobes with a pronounced broad keel or raised area along the midvein; fruits 1.01.5 mm wide, the fruit wall difficult to separate from the seed except for a loose area surrounding the style base, this usually appearing lighter colored and yellowish at fruit maturity ... 3. C. BERLANDIERI

Chenopodium berlandieri
31 16. Calyx lobes only slightly and narrowly keeled or raised along the midvein; fruits 1.52.2 mm wide, the fruit wall uniformly adhering to the seed, without a loose, lighter-colored apical portion ... 5. C. BUSHIANUM

Chenopodium bushianum
32 14. Fruits with the surface smooth or finely roughened, not appearing honeycombed

33 17. Calyx lobes covering the entire fruit, extending to the stylar region and tightly enclosing the fruit except for a minute area surrounding the style, occasionally somewhat spreading in a few flowers of a given inflorescence

34 18. Largest leaves with the middle lobe elongate, appearing narrowly oblong, more or less parallel sided for most of its length ... 8. C. FICIFOLIUM

Chenopodium ficifolium
35 18. Largest leaves with the middle lobe not elongate, appearing ovate to triangular, angled or tapered from near the base

36 19. Calyx lobed to about the midpoint, the fused portion extending beyond the broadest portion of the fruit ... 13. C. OPULIFOLIUM

Chenopodium opulifolium
37 19. Calyx lobed nearly to the base

38 20. Fruits 1.21.5 mm wide; largest (lowermost) leaves with the blades mostly 1.53.0 times as long as wide; stems often reddish-tinged or with reddish purple stripes, but usually lacking a pronounced reddish purple area at the base of each leaf ... 1. C. ALBUM

Chenopodium album
39 20. Fruits 0.91.1(1.2) mm wide; largest (lowermost) leaves with the blades mostly 1.21.5 times as long as wide; stems almost always reddish purple at each node (on the side on which the leaf is attached) ... 11. C. MISSOURIENSE

Chenopodium missouriense
40 17. Calyx lobes not covering the entire fruit, either not extending to the stylar region or only loosely enclosing the fruit (or both)

41 21. Leaves with the margins entire above the base, at most with a single pair of basal (or nearly basal) lobes

42 22. Calyx lobes keeled dorsally, extending to the stylar region or nearly so, but usually somewhat spreading, loosely covering most of the fruit ... 15. C. PRATERICOLA

Chenopodium pratericola
43 22. Calyx lobes flat, somewhat rounded, or pouched, or at most narrowly and shallowly keeled dorsally, extending past the widest part of the fruit but not reaching the stylar area, leaving much of the portion above the rim exposed ... 19. C. STANDLEYANUM

Chenopodium standleyanum
44 21. At least some of the leaves with the margins toothed above the base

45 23. Calyx lobes keeled dorsally along the midrib, the flower appearing more or less pentagonal when viewed from above

46 24. Leaf blades mostly with entire margins, only those of the largest (lowermost) leaves shallowly toothed; lowermost leaves with the blades mostly oblong-ovate ... 20. C. STRICTUM

Chenopodium strictum var. glaucophyllum
47 24. Leaf blades all or mostly with wavy to irregularly toothed margins, only those of the smallest (uppermost) leaves with the blades shallowly toothed; lowermost leaves with the blades triangular-ovate to rhombic

48 25. Calyx lobes relatively short, leaving most of the upper portion of the fruit exposed, the lobes glabrous or rarely sparsely mealy ... 21. C. URBICUM

Chenopodium urbicum
49 25. Calyx lobes relatively long, covering most of the fruit, the lobes sparsely to densely mealy

50 26. Fruits 1.21.5 mm wide; largest (lowermost) leaves with the blades mostly 1.53.0 times as long as wide; stems often reddish-tinged or with reddish purple stripes, but usually lacking a pronounced reddish purple area at the base of each leaf ... 1. C. ALBUM

Chenopodium album
51 26. Fruits 0.91.1(1.2) mm wide; largest (lowermost) leaves with the blades mostly 1.21.5 times as long as wide; stems almost always reddish purple at each node (on the side to which the leaf is attached) ... 11. C. MISSOURIENSE

Chenopodium missouriense
52 23. Calyx lobes flat or only slightly rounded or raised dorsally along the midrib, the flower appearing more or less circular in cross-section

53 27. Largest leaves 718 cm long, the margins of the blades with relatively few broad, coarse teeth; seeds 1.52.5 mm wide ... 18. C. SIMPLEX

Chenopodium simplex
54 27. Largest leaves 25(8) cm long, the margins of the blades wavy or with few to many relatively narrow, irregular teeth; seeds 0.51.5 mm wide

55 28. Seeds and fruits sharply angled along the margin (rim), the seeds dull ... 12. C. MURALE

Chenopodium murale
56 28. Seeds and fruits rounded or at most bluntly angled along the margin, the seeds shiny

57 29. Fruits (1.0)1.21.5 mm wide; leaf blades mostly linear to lanceolate or oblong lanceolate, those of only the lowermost leaves ovate to ovate-triangular ... 19. C. STANDLEYANUM

Chenopodium standleyanum
58 29. Fruits 0.91.2 mm wide; leaf blades mostly ovate-triangular, those of only the uppermost leaves linear to lanceolate ... 21. C. URBICUM Chenopodium urbicum
 
 
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