20. Agave gracilipes Trelease, Rep. (Annual) Missouri Bot. Gard. 22: 95, plates 98, 99. 1912.
Plants acaulescent, sparsely suckering; rosettes usually solitary, 3–4 × 7–8 dm, dense. Leaves 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 (1.8–)4–5 m. Inflorescences 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 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 sessile or short-pedicellate, oblong, 2.7–4.4 cm, apex beaked. Seeds 5–6.5 mm. 2n = 60.
Flowering summer--early fall. Gravelly to rocky, often calcareous places in grasslands, desert scrub, and pinyon juniper woodlands; 1200--1900 m; N.Mex., Tex.; Mexico (Chihuahua).
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).