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American agave, American century plant, centuryplant, maguey americano

golden-flower agave, goldenflower century plant

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.

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.

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.

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.

Seeds

6–8 mm.

6–7 mm.

2n

= 60.

Agave americana

Agave chrysantha

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
from USDA
sw United States; Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ
[WildflowerSearch map]
[BONAP county map]
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.)

Key
1. Leaves 80–135 cm, 4–6 times longer than wide; capsules 3.5–4 cm.
subsp. protamericana
1. Leaves 100–200 cm, 6–10 times longer than wide; capsules 4–8 cm.
subsp. americana
Source FNA vol. 26, p. 452. FNA vol. 26.
Parent taxa Agavaceae > Agave Agavaceae > Agave
Sibling taxa
A. asperrima, A. chrysantha, A. decipiens, A. delamateri, A. deserti, A. desmettiana, A. gracilipes, A. havardiana, A. lechuguilla, A. mckelveyana, A. murpheyi, A. neglecta, A. palmeri, A. parryi, A. parviflora, A. phillipsiana, A. schottii, A. shawii, A. sisalana, A. toumeyana, A. univittata, A. utahensis, A. weberi, A. ×ajoensis, A. ×arizonica, A. ×glomeruliflora
A. americana, A. asperrima, A. decipiens, A. delamateri, A. deserti, A. desmettiana, A. gracilipes, A. havardiana, A. lechuguilla, A. mckelveyana, A. murpheyi, A. neglecta, A. palmeri, A. parryi, A. parviflora, A. phillipsiana, A. schottii, A. shawii, A. sisalana, A. toumeyana, A. univittata, A. utahensis, A. weberi, A. ×ajoensis, A. ×arizonica, A. ×glomeruliflora
Subordinate taxa
A. americana subsp. americana, A. americana subsp. protamericana
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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