Agave americana

Linnaeus

Sp. Pl. 1: 323. 1753.

Treatment appears in FNA Volume 26. Treatment on page 452. Mentioned on page 444.

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.

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.

Selected References

None.

Key

1 Leaves 80–135 cm, 4–6 times longer than wide; capsules 3.5–4 cm. Agave americana subsp. protamericana
1 Leaves 100–200 cm, 6–10 times longer than wide; capsules 4–8 cm. Agave americana subsp. americana

"broadened" is not a number."dm" is not declared as a valid unit of measurement for this property.

... more about "Agave americana"
longitudinal +
2.5 cm25 mm <br />0.025 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
width +  and length +
glandular-pubescent +  and glandular +
papillate +
dark-brown +  and grayish +
subulate +  and conical +
2 cm20 mm <br />0.02 m <br /> (6 cm60 mm <br />0.06 m <br />) +
James L. Reveal +  and Wendy C. Hodgson +
Linnaeus +
armed +  and filiferous +
cross-zoned +, variegated +, light green +  and green or glaucous-gray +
lanceolate +
short to long +
thick +  and thin +
persistent +
reflexed +, erect +  and ascending +
triangular +
umbel-like +
short-pedicellate +
3.5 cm35 mm <br />0.035 m <br /> (8 cm80 mm <br />0.08 m <br />) +
fibrous-rooted +
sw United States +  and Mexico +
pubescent +  and glabrous +
6 cm60 mm <br />0.06 m <br /> (9 cm90 mm <br />0.09 m <br />) +
7 cm70 mm <br />0.07 m <br /> (10.5 cm105 mm <br />0.105 m <br />) +
loculicidal +
oblong +  and ovoid +
1/3 +  and 1/2 +
horizontal +  and slightly ascending +
10 cm100 mm <br />0.1 m <br /> (?) +
pseudopetiolate +, sessile +  and simple +
evergreen +
80cm;200cm +
15 cm150 mm <br />0.15 m <br /> (25 cm250 mm <br />0.25 m <br />) +
0.8 cm8 mm <br />0.008 m <br /> (2 cm20 mm <br />0.02 m <br />) +
1.2 cm12 mm <br />0.012 m <br /> (2 cm20 mm <br />0.02 m <br />) +
dentate +, serrulate +  and entire +
undulate to crenate +  and straight +
Fleshy (?) +, Firm (?) +  and Rigid (?) +
0.6 cm6 mm <br />0.006 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
constricted +
0.3 cm3 mm <br />0.003 m <br /> (?) +  and 0.6 cm6 mm <br />0.006 m <br /> (?) +
cylindrical +, ovoid +  and 3-angled +
3 cm30 mm <br />0.03 m <br /> (?) +  and 4.5 cm45 mm <br />0.045 m <br /> (?) +
succulent +
not +  and articulate +
umbel-like +
semisucculent +
not cespitose +
500 cm5,000 mm <br />5 m <br /> (900 cm9,000 mm <br />9 m <br />) +
globose +, obovoid +  and flattened +
semiwoody +
long-exserted +
branched +, , +  and unbranched +
aboveground +
3 +  and 1 +
papillate +
exserted +  and included +
subulate +
Agave americana +
species +
1 cm10 mm <br />0.01 m <br /> (4 cm40 mm <br />0.04 m <br />) +
0 cm0 mm <br />0 m <br /> (200 cm2,000 mm <br />2 m <br />) +
subequal +
2 cm20 mm <br />0.02 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
short-stemmed +  and acaulescent +
plant +  and suckering +
polycarpic +  and monocarpic +
small;gigantic +
petal-like +