Peter C. Hoch and Peter H. Raven

O. lamarckiana auct. mult., non SJringe in DC., Prodr. 3: 47. 1828; R. R. Stewart, Ann. Cat. Vasc. Pl. W. Pak. & Kashm. 508. 1972; O. erythrosepala Borbas, Magyar Bot. Lapok 2: 245. 1903; Raven in Tutin et al., Fl. Eur. 2: 306. 1968; Dietrich, Ann. Missouri Bot. Gard. 64: 616. 1978.

Plants usually biennial, forming a rosette, erect, with simple or much-branched main stem, 1-12 dm tall. Plants strigillose and coarsely erect villous, some to many of the hairs with a reddish-purple pustulate base, the inflorescence mixed villous and glandular-pubescent. Rosette leaves narrowly lanceolate to oblanceolate, 13-30 x 3-5 cm; cauline leaves narrowly elliptic to lanceolate, narrowed to the petiole, the uppermost sessile, 5-12 x 2.5-4 cm, bracts lanceolate to narrowly ovate, 1-3(-5) x 0.7-3.2 cm; all leaves undulate at the margins and sinuate-toothed to serrulate, sometimes reddish along the midrib. Inflorescence simple or branched: Floral tube 3.5-5 cm long. Sepals 2.8-4.2 cm long, red-striped along the midrib; sepal tips 5-8 mm long, spreading. Petals yellow, broadly obcordate, 3.5-5 cm long. Style 5-8 cm long, the stigma held above the anthers at anthesis. Capsule narrowly lanceolate in outline, 2-3 x 0.5-0.6 cm, green with a red median stripe on each valve, and with reddish-purple pustulate based hairs. Seeds prismatic, 1.3-2 x 1-1.5 mm. Self-compatible, but mostly outcrossing. Gametic chromosome number, n = 7 (ring of 12 and 1 bivalent at meiotic metaphase I).

Holotype: Brasil, Rio de Janeiro, Tijuca, 7 Feb. 1868, A. Glaziou 2568 (P, photo F. Isotypes, BR, G).

This attractive species is a common garden plant. In fact according to Raven et al. (Syst. Bot. 4: 248. 1979), O. glazioviana apparently originated through hybridization in a European garden between two species of sect. Oenothera subsect. Euoenothera prior to 1860, when it is known to have been in the horticultural trade. The cross probably involved O. biennis Linn. as one parent and O. grandiflora L'HJr. ex Ait. or O. elata H.B.K. as the other. The possibility also exists that the two parents were O. grandiflora and O. elata. Stewart (l.c. 508) lists O. biennis as a garden plant in Pakistan, but we have not seen any specimens; the plants to which he refers are apparently all O. glazioviana. Oenothera biennis is sharply distinct in its smaller flowers (10-25 mm long) and the stigma which is surrounded by the anthers at anthesis. Fl. Per.: Jun-Sep; Distribution: Widely distributed, but not known as a native plant anywhere, now naturalized on all continents except Antarctica; apparently not extensively naturalized in Pakistan at present.