Passiflora foetida Linnaeus var. arizonica Killip, Publ. Field Mus. Nat. Hist., Bot. Ser. 19: 490. 1938

Stems terete, densely hairy. Leaves pungent, densely hairy, glandular-ciliate; stipules pectinate, 1–8 × 1–4 mm, with glandular bristles or hairs; petiole with glandular bristles or hairs; blade roughly symmetric, 1.5–5 × 1–7 cm, moderately to deeply 3–5-lobed, middle lobe as long as or longer than lateral lobes, margins sharply dentate; abaxial fine veins weakly to moderately raised, abaxial nectaries absent. Floral bracts pinnatifid, 15–35 × 10– 28 mm, margins sharply dentate, with glandular bristles or hairs. Flowers: floral tube cuplike, 5–7 mm deep; sepals white, 17–38 × 6–9 mm; petals white, 16–30 × 6–12 mm; corona filament whorls 5–6, outer 2 whorls white basally, pale purple apically, linear, terete to transversely compressed, 9–25 mm. Berries green to yellow-green, ovoid, 20–35 × 18–30 mm.

Flowering Jun–Sep. Rocky, igneous slopes in semidesert grasslands and oak savannas; 1000–1800 m; Ariz.; Mexico (Sonora).

Passiflora arizonica is known only from portions of Pima and Santa Cruz counties, Arizona, and eastern Sonora, and has been confused with P. arida (D. H. Goldman 2003). It flowers during the summer rainy season, usually August and September. Unlike most other members of the genus, particularly those of sect. Dysosmia, to which it belongs, P. arizonica flowers in the evening, closing around midnight. The fragrant flowers have a deep floral cup, and may be pollinated by nocturnal moths.