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American agave, American century plant, centuryplant, maguey americano

Photo is of parent taxon

American century plant, wild 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 or short-stemmed, trunks less than 1 m; rosettes open.
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.

frequently reflexed, 80–135 × 17–22 cm;

blade light green to glaucous-gray, sometimes cross-zoned, broadly lanceolate, adaxially plane or guttered, abaxially convex;

margins crenate, teeth, 5–10 mm;

apical spine subulate, 3–6 cm.

Scape

5–9 m.

6–8 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.

lateral branches 15–20.

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.

7.5–9 cm;

perianth tube 15–20 mm;

ovary 4–4.5 cm.

Capsules

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

3.5–4 cm.

Seeds

6–8 mm.

7–8 mm.

Agave americana

Agave americana subsp. protamericana

Phenology Flowering early spring–early summer.
Habitat Sandy places in desert scrub
Elevation 200 m (700 ft)
Distribution
from USDA
sw United States; Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
TX; ne Mexico
[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.)

The Starr County, Texas, plants of subsp. protamericana are smaller in stature than those seen in Mexican populations but appear to belong to this wild taxon.

(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. 453.
Parent taxa Agavaceae > Agave Agavaceae > Agave > Agave americana
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 subsp. americana, A. americana var. americana, A. americana var. expansa
Subordinate taxa
A. americana subsp. americana, A. americana subsp. protamericana
Name authority Linnaeus: Sp. Pl. 1: 323. (1753) Gentry: Agaves Continental N. Amer., 287, figs. 12.1, 12.3–12.5, 12.8, 12.12, 12.14, 12.15, plate 12.1. (1982)
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