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American agave, American century plant, centuryplant, maguey americano

maguey puercoespín, Schott agave, Schott's century plant, shin dagger

Habit Plants acaulescent or short-stemmed, commonly suckering, trunks less than 2 m; rosettes not cespitose, 10–20 × 20–37 dm. Plants acaulescent, freely suckering; rosettes solitary or densely cespitose, 3–6 × 6–12 dm.
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.

mostly erect, widest near base, 20–40(–50) × 0.7–2.5 cm;

blade yellowish green or deep green, with or without conspicuous white bud-prints on both surfaces, linear, firm, adaxially plane or somewhat concave toward apex, abaxially convex to deeply convex toward base;

margins straight, filiferous or not, unarmed, fibers erect to spreading, sparse, white, filiform, brittle;

apex acuminate to long-acuminate, spine brown or grayish, acicular, 0.8–1.9 cm.

Scape

5–9 m.

1.6–4 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.

spicate or subspicate to narrowly racemose-paniculate, laxly flowered on distal 1/4–1/2;

bracts caducous, narrowly triangular, 2–4 cm;

peduncle 4 cm or shorter.

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.

1 or 2–3(–6) per cluster, erect, (2.9–)3–5 cm;

perianth yellow, tube funnelform, 8–11(–14) × 5–8(–13) mm, limb lobes erect to incurved, subequal, (7–)11–16 mm;

stamens slightly exserted;

filaments inserted high in perianth tube, 6–13 mm above tube base at 1 or 2 levels, erect, yellow, 1.5–2.2 cm;

anthers light to deep yellow, (7.5–)10–17 mm;

ovary 0.8–1.6 cm, neck constricted, 3–9 mm.

Capsules

short-pedicellate, oblong, 3.5–8 cm, apex beaked.

short-pedicellate, obovoid, 1–2.2 cm, apex rounded to beaked.

Seeds

6–8 mm.

3–3.5 mm.

Agave americana

Agave schottii

Distribution
from USDA
sw United States; Mexico
[WildflowerSearch map]
[BONAP county map]
from USDA
sw United States; nw Mexico
[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.)

Varieties 2 (2 in the flora).

(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
1. Leaves 0.7–1.2 cm wide, blade yellowish green, with conspicuous bud-prints, margins filiferous, apical spine 0.8–1.2 cm; flowers 2.9–4.2 cm; inflorescences spicate.
var. schottii
1. Leaves 1.2–2.5 cm wide, blade deep green, without bud-prints, margins nonfiliferous, apical spine 1.2–1.9 cm; flowers 3.5–5 cm; inflorescences subspicate to narrowly racemose-paniculate.
var. treleasei
Source FNA vol. 26, p. 452. FNA vol. 26, p. 447.
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. 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. 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
A. schottii var. schottii, A. schottii var. treleasei
Name authority Linnaeus: Sp. Pl. 1: 323. (1753) Engelmann: Trans. Acad. Sci. St. Louis 3: 305. (1875)
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