American Century Plant

The century plant or the American aloe is cultivated in gardens throughout Pakistan. It is not naturalized here and not grown for its fibre. This species is monocarpic, flowering after about 10 years of growth.

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.

The leaves are used medicinally and as a source of fiber.

Stem reduced. Leaves forming a rosette, curving outwards, the ends drooping, more than 1 m long, widest about the middle, neck not sharply constricted. green, sometimes glaucous, often with pale yellow borders or otherwise variegated, shallowly channelled only at the apical region. Apical spine c. 1 cm, dark reddish brown-black, marginal spines pointing downwards.

Plants acaulescent or short-stemmed, commonly suckering, trunks less than 2 m; rosettes not cespitose, 10–20 × 20–37 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. 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. 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. Capsules short-pedicellate, oblong, 3.5–8 cm, apex beaked. Seeds 6–8 mm.

Stems indistinct. Leaves usually 30--40 or more, in a massive basal rosette, oblanceolate, 1--2 m × 15--20 cm, fleshy, margin spiny, apex recurved and tipped with a dark brown spine 1.5--2.5 cm. Panicle many branched, 6--12 m, usually bearing few bulblets after anthesis. Perianth greenish yellow; tube ca. 1.2 cm; lobes 2.5--3 cm. Stamens ca. 2 × as long as perianth. Capsule oblong, ca. 5 cm.

Distribution: Mexico, naturalized in the Mediterranean region, India and Pakistan.

Widely cultivated. Naturalized in S China [native to tropical America].