Haseltonia 3: 133, figs. 1, 3–5. 1995.
Plants acaulescent, freely suckering; rosettes solitary to cespitose, 9–10 × 9–10 dm, open. Leaves erect or erect-ascending, 50–63(–73) × 7.5–9 cm; blade glaucous-gray to -bluish, cross-zoned, lanceolate or oblanceolate, rigid, adaxially concave, abaxially convex; margins straight or repand, armed, teeth single, well defined, 3.5–5 mm, 1–3 cm apart, interstitial teeth (3–)6–12, mostly along distal 2/3 of margins; apex conspicuously incurved, spine brownish gray, slender, 2.8–3.5(–4.9) cm. Scape 4.5–6 m. Inflorescences broadly paniculate, not bulbiferous, open; bracts persistent, triangular, 1–5.5 cm; lateral branches 12–17, horizontal, comprising distal 3/5–5/8 of inflorescence, longer than 10 cm. Flowers 14–20 per cluster, erect, 4.7–6.7(–7) cm; perianth cream, tinged with light green, tube not shallow, campanulate, 11–16 × 11–16 mm, limb lobes persistent and often leathery during and after anthesis, spreading, unequal, 9–18 mm, apex flushed with maroon; stamens long-exserted; filaments inserted at 1 level ca. mid perianth tube, erect, yellow, 3–5.3 cm, apex flushed with maroon; anthers yellow, 11–20 mm; ovary 2.1–2.9 cm, neck slightly constricted, 1–3.5 mm. Capsules not seen. Seeds unknown.
Phenology: Flowering early summer.
Habitat: Gravelly places with desert scrub, rarely in chaparral or pinyon-juniper woodlands
Elevation: 700–1600 m
Of conservation concern.
Agave delamateri is known only from about 90 individual clones and always in association with Mogollon or Salado settlement features. The plant is probably a cultivar derived from A. palmeri or a closely related taxon by pre-Columbian people. Agave delamateri hybridizes with A. chrysantha, acting as a pollen donor.