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American agave, American century plant, centuryplant, maguey americano

slim-footed agave, slimfoot 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, sparsely suckering; rosettes usually solitary, 3–4 × 7–8 dm, 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.

ascending, 18–30 × 4.5–7 cm;

blade glaucous and yellow- or gray-green, not cross-zoned, lanceolate to broadly lanceolate, rigid, adaxially concave toward apex, abaxially convex;

margins straight, armed, teeth single, well defined, 2–8 mm, 1.5–2.5 cm apart;

apical spine reddish brown to gray, acicular, 2.5–5 cm.

Scape

5–9 m.

(1.8–)4–5 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.

narrowly to somewhat broadly paniculate, dense, not bulbiferous;

bracts persistent, lanceolate, 1–3(–5) cm;

lateral branches 30–40, slightly ascending, comprising distal 1/3–1/2 of inflorescence, longer than 10 cm, or short-scaped individuals (1.8–3.5 m) with only 7–20 lateral branches on distal 1/4.

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.

6–45 per cluster, erect, 4–5.5(–5.8) cm;

perianth red in bud, yellow to yellow-green at anthesis, tube broadly campanulate, 4–7 × 9–15 mm, limb lobes spreading to ascending, slightly unequal, 14–18 mm;

stamens long-exserted;

filaments inserted just below rim of perianth tube, erect, yellow, (2.8–)3–4.5 cm;

anthers yellow, 16–20 mm;

ovary 2.5–3.2 cm, neck constricted, 3–5 mm.

Capsules

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

sessile or short-pedicellate, oblong, 2.7–4.4 cm, apex beaked.

Seeds

6–8 mm.

5–6.5 mm.

2n

= 60.

Agave americana

Agave gracilipes

Phenology Flowering summer–early fall.
Habitat Gravelly to rocky, often calcareous places in grasslands, desert scrub, and pinyon juniper woodlands
Elevation 1200–1900 m (3900–6200 ft)
Distribution
from USDA
sw United States; Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
NM; TX; Mexico (Chihuahua)
[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 gracilipes probably represents an ancient hybrid involving A. lechuguilla and A. parryi subsp. neomexicana. In fact, hybrids between A. gracilipes and A. lechuguilla appear to occur at present. However, until populations of A. gracilipes are thoroughly studied cytologically, we are reluctant to designate this taxon as a hybrid species (e.g., see 8. A. ×arizonica).

(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, p. 458.
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. 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
Name authority Linnaeus: Sp. Pl. 1: 323. (1753) Trelease: Rep. (Annual) Missouri Bot. Gard. 22: 95, plates 98, 99. (1912)
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