Crotalaria
Crotalaria juncea
rabbitbells, rattlebox
sunn hemp
erect, ascending, spreading, decumbent, or prostrate, glabrous or pubescent.
erect, 100–200(–400) cm, densely, loosely strigose, hairs appressed-ascending, yellowish to golden brown.
alternate, palmately compound or unifoliolate;
stipules present or absent, usually persistent, filiform to foliaceous;
petiolate or subsessile;
leaflets 1 or 3[–7], stipels absent, blades 5–150 mm, margins entire, surfaces glabrous or pubescent.
unifoliolate;
stipules filiform, not decurrent on stem, 1–2 mm;
blade linear-elliptic to oblong, 50–150 mm, length 2.5–4 times width, surfaces strigose, more densely so abaxially.
6–20-flowered, terminal, subterminal, or axillary, open, 10–50 cm;
bracts persistent, narrowly ovate-lanceolate, 3–5 mm.
(1 or)2–50-flowered, usually terminal or subterminal, leaf-opposed, rarely axillary, racemes [heads or flowers solitary or fascicled];
bracts present, persistent or caducous;
bracteoles present, paired proximal to calyx.
papilionaceous;
calyx usually cylindrical, rarely campanulate or cupulate, lobes 5;
corolla usually yellow, sometimes orangish, rarely white, blue, or lavender, glabrous or hairy outside;
stamens 10, monadelphous;
anthers alternately basifixed on long filaments and dorsifixed on small filaments, dehiscing longitudinally;
style with 1 or 2 lines of hairs adaxially;
stigma terminal, usually bilobed.
calyx broadly cylindrical, 1.5–2 mm, lobes triangular-lanceolate, glabrous or slightly puberulous;
corolla deep, bright yellow, sometimes with faint reddish lines, 15–22 mm.
legumes, subsessile to long-stipitate, usually inflated, globose, ovoid to ellipsoid, or cylindrical, dehiscent, often tardily so, glabrous or pubescent.
25–45 × 12–17 mm, densely hirsute-pilose, hairs yellow-brown.
1–70, oblique-cordiform to oblong-reniform;
hilar sinus obvious, aril sometimes conspicuous.
= 7, 8.
Crotalaria
Crotalaria juncea
Species ca. 600 (15 in the flora).
Crotalaria biflora Linnaeus (native to India) was collected in 1959 as a waif on chrome ore piles in Newport News, Virginia (C. F. Reed 1964). The species is an annual, distinguished as hirsute-villous to subsericeous, stems prostrate, 5–12 cm, leaves sessile, unifoliolate, blades ovate to oblong or oblong-ovate, surfaces villous-hirsute, flowers one or two, on axillary peduncles, and hirsute, ovoid to cylindrical-ovoid legumes.
Crotalaria alata Buchanan-Hamilton ex D. Don (native to Himalayan Asia) was collected in 1939 as an escape in Gainesville, Florida (W. A. Murrill s.n., MO); subsequently, it has not been recorded in the flora area. The species is perennial, distinguished as hirsute to strigose-hirsute, stems erect, 10–20 cm, leaves unifoliolate, blades lanceolate to elliptic-lanceolate or elliptic, stipules decurrent, forming wings on internodes, and apically bilobed, flowers in terminal and axillary racemes, 4–10 cm, and legumes glabrous.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
The antiquity of the cultivation of Crotalaria juncea makes nativity difficult to interpret, but the species is now widely cultivated throughout India and Pakistan as well as other parts of the world, including Australia and Russia. The strong bast fiber of the bark has long been used in twine, rug yarn, cordage, cigarette and tissue papers, fish nets, sacking, and canvas. Plants of C. juncea are extremely fast-growing and are widely used throughout the tropics as so-called green manure to add nutrients and organic matter to the soil.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Leaves 3-foliolate. | → 2 |
2. Leaflet blades 5–15(–35) mm; legumes 7–20 mm. | → 3 |
3. Stems mostly decumbent to prostrate, minutely and sparsely strigillose; legumes. | C. pumila |
3. Stems erect to decumbent, loosely strigose to strigose-hirsute; legumes 7–10 mm. | C. virgulata |
2. Leaflet blades (10–)20–130(–180) mm; legumes (16–)18–70 mm. | → 4 |
4. Leaflet blades linear to linear-lanceolate, elliptic-lanceolate, or lanceolate, lengths 5–10 times widths. | → 5 |
5. Racemes 12–26(–40)-flowered; corollas 8–11 mm; legumes 4–6 mm diam. | C. lanceolata |
5. Racemes 4–12-flowered; corollas 18–20 mm; legumes (10–)15–20 mm diam. | C. ochroleuca |
4. Leaflet blades obovate, ovate, elliptic-obovate, elliptic-oblanceolate, elliptic, elliptic-lanceolate, or spatulate-obovate, lengths 1.3–4.5 times widths. | → 6 |
6. Stipules absent; leaflet blades elliptic to elliptic-lanceolate, or elliptic-oblanceolate, 40–100(–140) mm, lengths 3–4.5 times widths; calyces basally truncate and deflexed against pedicels. | C. trichotoma |
6. Stipules usually present (persistent or caducous); leaflet blades elliptic, ovate, obovate, elliptic-obovate, or spatulate-obovate, (10–)20–70 mm, lengths 1.3–2.5 times widths; calyces sometimes basally truncate, not deflexed against pedicels. | → 7 |
7. Legumes 5–6 mm diam., slightly to conspicuously curved, minutely puberulent to glabrate; stems strigose; leaflet surfaces strigillose abaxially, glabrous adaxially. | C. pallida |
7. Legumes 10–15 mm diam., straight, villous-hirsute to hispid-hirsute; stems hirsute-villous to strigose-hirsute; leaflet surfaces glabrous or hairy on abaxial midvein. | C. incana |
1. Leaves unifoliolate. | → 8 |
8. Corollas usually blue to lavender, sometimes white or pale yellow tinged blue; stipules present, often encircling nodes. | C. verrucosa |
8. Corollas bright yellow; stipules present and not encircling nodes, or absent. | → 9 |
9. Stipules decurrent on mid and distal stems. | → 10 |
10. Herbs annual; stems erect to decumbent, hirsute-pilose; leaflet blade lengths 4–8 times widths. | C. sagittalis |
10. Herbs perennial; stems decumbent, prostrate, ascending, or erect, strigose or strigose-sericeous to hirsute-villous; leaflet blade lengths 1–12 times widths. | → 11 |
11. Leaflet blades linear-lanceolate, linear-oblanceolate, linear, oblong, or elliptic (narrower distally), lengths (2–)4–10 times widths, surfaces glabrous adaxially; stems erect to ascending. | C. purshii |
11. Leaflet blades broadly elliptic to elliptic-ovate, ovate, broadly lanceolate, linear, linear-lanceolate, or obovate-oblanceolate, lengths 1–12 times widths, surfaces strigose to strigose-hirsute adaxially; stems prostrate to decumbent or ascending. | C. rotundifolia |
9. Stipules, when present, not decurrent on stems. | → 12 |
12. Herbs perennial; stipules absent; leaflet blades (5–)8–19 mm; stems 2–10 cm; corollas 8–9 mm. | C. avonensis |
12. Herbs annual; stipules usually present; leaflet blades 30–150 mm; stems 30–200(–400) cm; corollas 15–25 mm. | → 13 |
13. Stipules ovate to ovate-lanceolate, 4–7 mm; floral bracts 5–8 mm, persistent; stems glabrous. | C. spectabilis |
13. Stipules, when present, filiform or setaceous, 1–2 mm; floral bracts 2–5 mm, persistent or caducous; stems strigose or strigose-sericeous. | → 14 |
14. Leaflet blades obovate to spatulate or oblanceolate, 30–80 mm, lengths. | → 2 |
2. 2–3(–4) times widths; stems 30–90 cm. | C. retusa |
14. Leaflet blades linear-elliptic to oblong, 50–150 mm, lengths 2.5–4 times widths; stems 100–200(–400) cm. | C. juncea |
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