Eulobus

Nuttall ex Torrey & A. Gray

Fl. N. Amer. 1: 514. 1840.

Etymology: Greek eu, good or well, and lobos, capsule, alluding to long, linear pods
Synonyms: Camissonia sect. Eulobus (Nuttall ex Torrey & A. Gray) P. H. Raven Oenothera sect. Eulobus (Nuttall ex Torrey & A. Gray) Baillon Oenothera subg. Eulobus (Nuttall ex Torrey & A. Gray) Munz
Treatment appears in FNA Volume 10.
 TaxonIllustrator 
FNA10 P24 Tetrapteron graciliflorum.jpgTetrapteron graciliflorum
Neoholmgrenia hilgardii
Neoholmgrenia andina
Eulobus californicus

Herbs, annual, [perennial, subshrubs], caulescent; with a taproot. Stems erect [to prostrate], unbranched or branched. Leaves cauline, sometimes also in basal rosette, alternate; stipules absent; sessile or petiolate; blade pinnatifid to lobed, [subentire]. Inflorescences open spikes, erect. Flowers bisexual, actinomorphic, buds erect; floral-tube relatively short, deciduous (with sepals, petals, and stamens) after anthesis, lined with a lobed, fleshy nectary disc [or with rounded, fleshy disc at base of style]; sepals 4, reflexed separately, in pairs, or as a unit, (rarely spreading); petals 4, yellow, fading orangish red, usually finely flecked with red near base; stamens 8, in 2 subequal series or epipetalous series shorter, anthers versatile, pollen shed singly; ovary 4-locular, stigma globose to cylindrical, surface wet and non-papillate. Fruit a capsule, straight or slightly curved [contorted], somewhat torulose or subterete, loculicidally dehiscent, midrib of each valve prominent; sessile. Seeds numerous, in 1 row per locule, narrowly obovoid, ± triangular in cross-section, finely papillose. = 7.

Distribution

sw United States, nw Mexico

Discussion

Species 4 (1 in the flora).

Eulobus is characterized by olive brown seeds with distinct purple spots, yellow petals with maroon flecks near the base, the distal part ultraviolet-reflective, leaves mostly lobed or pinnatifid, and capsules somewhat contorted or straight, and often sharply reflexed at maturity. R. A. Levin et al. (2004) included E. californicus and E. crassifolius (Greene) W. L. Wagner & Hoch (a species of Baja California, Mexico) in their molecular analysis and found Eulobus to be strongly supported as monophyletic; they also found that Eulobus plus (Chylismia plus Oenothera) formed a weakly supported clade. Reproductive features include: self-incompatible [E. crassifolius, E. sceptrostigma (Brandegee) W. L. Wagner & Hoch] or self-compatible [E. angelorum (S. Watson) W. L. Wagner & Hoch, E. californicus], flowers diurnal, outcrossing and pollinated mainly by small oligolectic bees (E. G. Linsley 1963b, 1973) or autogamous (P. H. Raven 1969).

Selected References

None.

... more about "Eulobus"
Warren L. Wagner +
Nuttall ex Torrey & A. Gray +
indehiscent +  and loculicidal +
lobed +, toothed +  and entire +
pinnatifid +  and lobed +
curved +  and straight +
subterete +  and torulose +
sw United States +  and nw Mexico +
Greek eu, good or well, and lobos, capsule, alluding to long, linear pods +
basifixed +  and versatile +
actinomorphic +
curved +  and straight +
subterete +  and torulose +
deciduous +
numerous +  and 1 +
flecked +, red +, fading orangish +  and yellow +
Fl. N. Amer. +
basal +  and cauline +
clavate +  and globose +
7 +  and numerous +
papillose +
triangular +  and obovoid +
purple +, pink +, red +  and green +
deciduous +
parenchymatous +
parietal +, axile +  and placentation +
subequal +
aquatic +, amphibious +  and terrestrial +
2 times as many or as many as sepals +
branched +  and unbranched +
prostrate +  and decumbent +
globose +  and cylindrical +
petiolate +  and sessile +
intrapetiolar +
aquatic +, amphibious +  and terrestrial +
non-papillate +
Camissonia sect. Eulobus +, Oenothera sect. Eulobus +  and Oenothera subg. Eulobus +
Eulobus +
Onagraceae tribe Onagreae +
3(-5)-aperturate +
smooth +  and erose +
papillate +