Oenothera neomexicana
Oenothera flava
New Mexico evening-primrose
long-tubed evening primrose, yellow evening primrose
erect or ascending, unbranched or branched, 30–60 cm.
(when present) ascending, 1–several, usually densely leafy, 0–2 cm.
in a basal rosette and cauline, rosette weakly developed or absent, at least during flowering, 3–9 × (0.6–)1–2.5 cm;
petiole 0–2 cm;
blade oblong to lanceolate or narrowly ovate, margins irregularly sinuate-dentate.
primarily in a basal rosette, (3.4–)6–30(–36) × (0.5–)1.5–5(–7) cm, flexible, sometimes ± fleshy;
petiole (0.2–)2–7(–10) cm;
blade oblanceolate to linear, margins usually irregularly and coarsely pinnately lobed, rarely subentire, apex acute.
1–several opening per day near sunset;
buds nodding, weakly quadrangular, with free tips 0.5–4 mm;
floral tube 30–50 mm;
sepals 20–30 mm, not spotted;
petals white, fading pink, broadly obovate, 20–30 mm;
filaments 10–15 mm, anthers 8–15 mm;
style 50–70 mm, stigma exserted beyond anthers at anthesis.
1–4 opening per day near sunset;
buds with free tips (1–)2–10(–12) mm;
floral tube (24–)40–200(–265) mm;
sepals (8–)11–40(–42) mm;
petals bright yellow, sometimes paler (in smaller-flowered plants), fading pale orange, drying purple, (7–)10–45(–50) mm;
filaments (5–)8–23(–26) mm, anthers (2–)3–13(–16) mm;
style (40–)50–250(–290) mm, stigma exserted beyond or surrounded by ring of anthers.
erect or strongly ascending, not woody, straight or slightly curved, subcylindrical, obtusely 4-angled, tapering gradually from base to apex, 20–30 × 2–3 mm;
sessile.
leathery in age, surface usually conspicuously reticulate, usually narrowly ovoid or ellipsoid, sometimes ovoid or lanceoloid, winged, wings narrowly oblong, (2–)3–5(–6) mm wide, confined to distal 2/3 of capsule, (10–)20–35(–43) × 4–8 mm (excluding wings), gradually constricted to a short beak, dehiscent 1/4–1/2 their length, valve surface usually conspicuously reticulate;
sessile.
numerous, in 1 row per locule, dark brown, narrowly obovoid, 1.5 mm.
asymmetrically cuneiform, 1.8–2.2(–2.6) mm.2n = 14.
= 14.
Oenothera neomexicana
Oenothera flava
Oenothera neomexicana is known from central to western New Mexico west of the Rio Grande Valley, except for the Organ Mountains, and eastern and central Arizona from the White Mountains south to Mount Graham and northwestward across the Mogollon Rim in Coconino and Yavapai counties. Oenothera neomexicana had been assumed to be self-incompatible (W. L. Wagner et al. 2007), but K. E. Theiss et al. (2010) determined one population sampled to be consistently self-compatible.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Petals in Oenothera flava typically range from 7–32 mm with floral tubes 24–100 mm; however, plants from three disjunct areas: the Mogollon Plateau in Arizona to Catron County, New Mexico; Sacramento Mountains and Sierra Blanca, Lincoln and Otero counties, New Mexico; and the Sierra Madre Occidental from northern Chihuahua south to Durango, have much larger petals (30–55 mm) and longer floral tubes (80–265 mm). They were originally recognized as a distinct species or most recently as a subspecies (O. flava subsp. taraxacoides), but detailed study of the variation pattern suggests that the larger flowers occur in areas of high hawkmoth species diversity and higher rates of outcrossing, similar to the pattern discussed in detail by D. P. Gregory (1963, 1964). R. A. Raguso et al. (2007) and H. E. Summers et al. (2015) came to the same conclusion in an independent study of floral biology of sect. Lavauxia. Because populations from the three disjunct areas appear to have diverged independently from lower-elevation source populations, it seems best to treat the complex as one variable species without any formal subdivision.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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