Agave americana |
Agave chrysantha |
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American agave, American century plant, centuryplant, maguey americano |
golden-flower agave, goldenflower century plant |
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Habit | Plants acaulescent or short-stemmed, commonly suckering, trunks less than 2 m; rosettes not cespitose, 10–20 × 20–37 dm. | Plants acaulescent, occasionally suckering; rosettes solitary or infrequently cespitose, 0.5–1.2 × 0.8–1 dm, rather open to somewhat dense. | ||||
Leaves | erect, spreading to ascending, occasionally reflexed, 80–200 × 15–25 cm; blade light green to green or glaucous-gray, sometimes variegated or cross-zoned, narrowly to broadly lanceolate, smooth, rigid; margins nearly straight or undulate to crenate, armed, teeth single, 5–10 mm, 1–4 cm apart; apical spine dark brown to grayish, conical or subulate, 2–6 cm. |
spreading to ascending, 40–75(–82) × (4–)8–10(–11) cm; blade pale to glaucous or yellowish green to green, not cross-zoned, linear-lanceolate to lanceolate, rigid, adaxially deeply guttered, abaxially convex; margins undulate to wavy, armed, teeth single, well defined, 4–10 mm, (0.8–)1–3(–4) cm apart, interstitial teeth (0–)1–3(–5), mostly along distal 2/3 of margins; apical spine reddish brown or brown to gray, acicular, 2.5–4.5 cm. |
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Scape | 5–9 m. Inflorescences paniculate, not bulbiferous; bracts persistent, triangular, 5–15 cm; lateral branches 15–35, horizontal to slightly ascending, comprising distal 1/3–1/2 of inflorescence, longer than 10 cm. |
4–7 m. Inflorescences narrowly to broadly paniculate, open, not bulbiferous; bracts persistent, triangular, 1–5 cm; lateral branches (6–)8–18, slightly ascending, comprising distal 1/4–1/3 of inflorescence, longer than 10 cm. |
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Flowers | erect, 7–10.5 cm; perianth yellow, tube funnelform to cylindric, 8–20 × 12–20 mm, limb lobes erect, subequal, 20–35 mm; stamens long-exserted; filaments inserted above mid perianth tube, erect, yellow, 6–9 cm; anthers yellow, 25–35 mm; ovary 3–4.5 cm, neck constricted, 3–6(–8) mm. |
12–21 per cluster, erect, 3.5–6.5(–6.7) cm; perianth golden yellow, tube not shallow, campanulate, 6–18 × (7–)10–21(–26) mm, limb lobes erect persistent and often leathery during and after anthesis, strongly unequal, (6–)9–15(–18) mm; stamens long-exserted; filaments inserted at 2 levels ca. mid perianth tube, erect, pale yellow, (3.2–)3.5–5 cm; anthers yellow, 7–20 mm; ovary (1.4–)2.2–3(–3.3) cm, neck slightly constricted, (0.5–)4–6(–8) mm. |
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Capsules | short-pedicellate, oblong, 3.5–8 cm, apex beaked. |
sessile or short-pedicellate, narrowly oblong to obovoid, 3.5–5 cm, apex short-beaked. |
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Seeds | 6–8 mm. |
6–7 mm. |
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2n | = 60. |
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Agave americana |
Agave chrysantha |
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Phenology | Flowering late spring–summer. | |||||
Habitat | Sandy to gravelly places on granitic or volcanic soils in desert scrub, grasslands, pinyon-juniper, and oak woodlands | |||||
Elevation | 700–2100 m (2300–6900 ft) | |||||
Distribution |
sw United States; Mexico
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AZ
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Discussion | Subspecies 2 (2 in the flora). Various chromosome numbers have been reported for Agave americana under a variety of names, typically without regard to the plant’s origin or its precise taxonomic disposition. Nonetheless, the species is most certainly a polyploid complex based on x = 30, with reports of n = 30 and 2n = 60, 120, and 180 documented by S. D. McKelvey and K. Sax (1933), H. Matsuura and T. Sutô (1935), E. B. Granick (1944), A. K. Sharma and U. C. Bhattacharyya (1962), M. S. Cave (1964), S. Banerjee and A. K. Sharma (1987), Huang S. F. et al. (1989) and B. Vijayavalli and P. M. Mathew (1990). Various dysploids have also been reported (A. F. Dyer et al. 1970; J. L. Strother and G. L. Nesom 1997). See H. S. Gentry (1982) for details. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Agave chrysantha hybridizes with A. murpheyi, A. palmeri, A. parryi var. couesii, and A. delamateri. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 26, p. 452. | FNA vol. 26. | ||||
Parent taxa | ||||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | A. palmeri var. chrysantha | |||||
Name authority | Linnaeus: Sp. Pl. 1: 323. (1753) | Peebles: Proc. Biol. Soc. Wash. 48: 139. (1935) | ||||
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