Tetrapteron graciliflorum
Onagraceae subfam. onagroideae
Hill sun cup, slender flower evening primrose
rarely with ascending lateral branches to 2.5 cm.
blade linear to very narrowly lanceolate, 1–9.8 ×0.1–0.9 cm, dilated at base, margins entire or very sparsely serrulate.
stipules present or absent.
opening near sunrise;
floral tube 1.6–3.2 mm;
sepals 4.5–8 mm;
petals 5–18 mm; episepalous filaments 1.8–3.2 mm, epipetalous filaments 0.8–1.6 mm;
sterile projection of ovary 6–45 mm;
style 3–5.5 mm, short-hairy near base;
stigma 1–1.6 mm diam., surrounded by anthers of longer stamens at anthesis.
floral tube present or, rarely, absent;
sepals 2 or 4 (very rarely 3), deciduous with floral tube, petals, and stamens;
petals yellow, white, pink, red, rarely in combination.
irregularly obovoid, sharply 4-angled, thick-walled, somewhat woody, with pointed wing near center-top of each valve, 4–8 × 2.6–4.8 mm, tardily dehiscent in distal 1/3.
tan with dark splotches, obovoid, 1.2–2 mm.
= 14.
Tetrapteron graciliflorum
Onagraceae subfam. onagroideae
Tetrapteron graciliflorum is rare in Oregon, known only from a few collections in Jackson and Josephine counties. In Baja California, Mexico, it is known only from Rancho Aguajito.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Genera 21, species 582 (16 genera, 246 species in the flora).
Onagroideae encompass the main lineage of the family, after the early branching of Ludwigia (R. A. Levin et al. 2003, 2004). This large and diverse lineage is distinguished by the presence of a floral tube beyond the apex of the ovary; sepals deciduous with the floral tube, petals, and stamens; pollen shed in monads (or tetrads in Chylismia sect. Lignothera and all but one species of Epilobium); ovular vascular system exclusively transseptal (R. H. Eyde 1981); ovule archesporium multicellular (H. Tobe and P. H. Raven 1996); and change in base chromosome number from x = 8 in Ludwigia to x = 10 or x = 11 at the base of Onagroideae (Raven 1979; Levin et al. 2003). Molecular work (Levin et al. 2003, 2004) substantially supports the traditional tribal classification (P. A. Munz 1965; Raven 1979, 1988); tribes are recognized to delimit major branches within the phylogeny of Onagroideae, where the branches comprise strongly supported monophyletic groups of one or more genera.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
CA, 
OR - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
