Oenothera speciosa

Oenothera speciosa Nutt, J. Acad. Nat. Sci. Philadelphia 2: 119. 1821.

Perennial or annual herb, rhizomatous, decumbent to ascending, 15-60 cm tall. Stem cylindric, erect or sprawling, green to ashy grey, red-purple at base on aging. Leaves basal and cauline, basal when shoots young; sessile or petiolate, petiole 0.5-2.5 cm long; leaf blade variable on the same plant, 1-6(-10) cm x 0.3-2.5 cm, elliptic, oblong, lanceolate, oblanceolate or obovate, base cuneate, apex acute, margin entire, wavy, dentate, serrate or occasionally pinnately lobed at base; midrib sunken adaxially and raised abaxially; glabrous or sparsely appressed-pubescent. Flowers solitary axillary (up to 3) in upper part of stem/ branches; flower buds long, spindle-shaped; anthesis usually at pre-dawn/ sunset. Flowers bisexual, actinomorphic, 4-merous, epigynous, white turning to pink-rose, 3.5-5 cm across; pedicels 1-3 mm long grading into narrowed ovary base. Hypanthium narrowly funnel-shaped, 1-1.5 cm x 2.5 mm, light green, 8-ribbed, pubescent internally with non-glandular hairs facing style, nectary at its base, extended beyond ovary into floral tube, deciduous soon after anthesis. Calyx lobes (Sepals) 4, fused, split along 1 suture line base to tip, short reflexed at base and then ascending and appressed to corolla; calyx unit (4-sepal unit) cupped, broadly ovate and 1-sided; individually narrowly lanceolate to linear, 1.5-2.5 cm x 2.5-3 mm, greenish with red margins, apex acuminate. Petals 4, free, spreading forming dish-shaped corolla, equal or slightly unequal, obcordate or obovate, 1.5-3 cm x 1.5-2.5 cm, pink to purplish pink or rose, base yellowish green, palmately veined with rose veins, glabrous. Stamens 8, in 1 series, arising as fused ring from hypanthium rim and barely fused to basal edge of petals, monomorphic; filaments erect, 1.5-1.7 cm long, white but yellow at enlarged base, glabrous; anthers exserted, versatile, bithecous, linear, 9-11 mm long, pale yellow, longitudinally dehiscent, pollens held in a mass by minute threads (viscin threads). Pistil 1, ovary inferior, club-shaped, up to 1.8 cm long, lower portion tapered, upper portion conspicuously 8-ribbed, 4-locular, many ovules in each loculus, axile placentation; style exserted to level of anthers, 3-3.4+ cm long, white, densely puberulent at base; stigma 4-lobed, lobes spreading, finger-like, 4-7 mm long, white, cross-like. Fruit capsule, loculicidal, 4-valved, many-seeded, club- shaped to obovoid, 1-1.8 cm long, enlarged upper portion conspicuously 8-ribbed, dehiscing only in upper part forming 4 deltate valves. Sepals not persistent. Seeds in many vertical stacks per chamber. Seeds asymmetrically obovoid, ca. 1 mm long, brown.

Flowering and Fruiting: March to May
Common Names: Pink ladies, Pink Evening Primrose, Showy Evening Primrose, Mexican Primrose, Amapola Del Campo, Mexican Evening Primrose