Oenothera capillifolia
Oenothera filiformis
bee-blossom, longflower beeblossom
1–many, weakly decumbent to ascending or erect, unbranched to moderately branched, (10–)25–80 cm.
usually well-branched distal to base, (50–)100–400 cm.
1–9 × (0.1–)0.3–1 cm, sometimes fascicles of small leaves to 2 cm present in non-flowering axils;
petiole 0–0.6 cm;
blade linear to narrowly lanceolate or oblanceolate, often folded lengthwise, usually not much reduced distally, proximalmost leaves sometimes spatulate, base attenuate, margins subentire or serrulate or spinulose-serrate, apex acute.
in a basal rosette and cauline, basal 8–15(–40) × 1.5–3.6 cm, blade lyrate, margins irregularly toothed to lobed;
cauline 1.5–13 × 0.5–3 cm, blade narrowly elliptic to elliptic or lanceolate, margins subentire or shallowly undulate-denticulate.
opening at sunrise;
buds with free tips 0–4 mm;
floral tube 5–20 mm;
sepals 4–12 mm, midribs keeled;
petals yellow, fading orangish to purplish, 6–25 mm; antisepalous filaments 2–8 mm, antipetalous filaments 1–4 mm, anthers 2–7 mm, pollen 90–100% fertile;
style 9–30 mm, stigma sometimes blue-black, discoid to quadrangular, exserted beyond anthers.
4-merous, zygomorphic, opening at sunset;
floral tube 4–13(–15) mm;
sepals 7–18 mm;
petals white, fading pink, elliptic to elliptic-obovate, 7–15 mm;
filaments 5–13 mm, anthers 1.5–5 mm, pollen 90–100% fertile;
style 12–34 mm, stigma exserted beyond anthers at anthesis.
10–35 × 1–2 mm, hard, dehiscent 1/2 their length, often tardily dehiscent throughout their length.
ellipsoid or ovoid, sharply 4-angled, 4.5–7 × 1.5–2.5 mm;
sessile.
obovoid, 1–1.8 mm, sharply angled, apex truncate.
2–4, yellowish to reddish brown, 1.3–3 × 0.7–1.3 mm.
= 14.
Oenothera capillifolia
Oenothera filiformis
Subspecies 2 (2 in the flora).
Oenothera capillifolia is self-incompatible (H. F. Towner 1977).
Oenothera berlandieri (Spach) Steudel 1841, not D. Dietrich 1840, is superfluous and cannot be used in Oenothera when transferred from Calylophus, and pertains here.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
P. H. Raven and D. P. Gregory (1972[1973]) found various levels of hybridization and intergradation between Oenothera filiformis and O. lindheimeri to occur where their ranges overlap. In the region of geographical overlap, most populations of O. filiformis are strigillose in the inflorescences and have evening-opening flowers, while O. lindheimeri is villous in the inflorescences, and has large morning-opening flowers. Moreover, O. lindheimeri occurs only on black clay prairie soil, while O. filiformis occurs in light, sandy soil, as it does throughout its range, and in more disturbed areas. Despite these differences, Raven and Gregory found hybridization between these species scattered across an area from eastern Texas across Louisiana to Alabama. At some locations there is apparently no hybridization, while at others hybrids were uncommon to relatively common. Intermediate morning-blooming plants in Alabama appear to represent evidence of past hybridization since O. lindheimeri does not occur there. Many of the individuals they tested had somewhat reduced pollen fertility (40–70% fertile). They suspected that habitat disturbance was primarily responsible in many cases, but they also detected what may have been intergradation resulting from past hybridization outside of the current distribution of O. lindheimeri. Many of these individual cases deserve further investigation to better understand the dynamics of the interactions between these species and if any of the interactions have led to stabilization of novel populations that might be recognized taxonomically.
Very few collections have been made from areas on the periphery of the range of Oenothera filiformis (southern Ontario, Connecticut, Maryland, Massachusetts, Pennsylvania), and populations in these areas probably represent recent human-based introductions. P. H. Raven and D. P. Gregory (1972[1973]) determined O. filiformis to be self-incompatible.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Stems 1–several, ascending to erect, 30–80 cm; leaves 2.5–9 cm. | subsp. capillifolia |
1. Stems several–many, decumbent to ascending, (10–)25–40 cm; leaves 1–4 cm. | subsp. berlandieri |
WildflowerSearch
iNaturalist
Go Botany
IL Wildflowers
KS Wildflowers
LA Plants
MD Biodiversity
MI Flora
MO Plants
USDA Plants Database
