Oenothera fallax Renner, Z. Indukt.

Woźniak-Chodacka, Monika, 2023, Lectotypification, epitypification and taxonomic notes on Oenothera fallax (Onagraceae), Phytotaxa 612 (3), pp. 283-292 : 285-289

Oenothera fallax Renner, Z. Indukt. Abstammungs- Vererbungsl. 18(3‒4): 176. 1917.

Type:— GERMANY. Based on an artificial hybrid between a strain of O. glazioviana [‘ O. lamarckiana Heribert-Nielson’] and a strain of O. biennis [ O. biennis München from the Botanical Garden Münich]. Lectotype (designated here):—Figure 20 in Renner 1917: 177. Epitype (designated here):— POLAND. Dolnośląskie: Wrocław , in ruins along Podwale Street , near Oławska Street , 16 July 1962, K. Rostański s.n., 2 sheets ( WRSL!, barcodes 4009786 and 4009787 ). Figs. 1‒2 .

Morphology: —Stem over 100 cm tall, with branches, green or somewhat reddened, distinctly red-punctulated, with numerous long stiff hairs with bulbous red bases and shorter arcuate hairs. Leaves elliptic to ovato-lanceolate, with white or reddish midrib, denticulate, the lower ones crinkled ( Fig. 3 ). Rhachis green, red punctulated ( Fig. 4 ), reddened at apex with numerous glandular hairs and stiff hairs with red bulbous bases. Buds red-striped ( Fig. 5 ), covered with glandular and stiff hairs; sepal tips 2‒4 mm, appressed below, divergent to appressed above. Hypanthia 30‒40 mm long. Petals yellow, obcordate, relatively large, 20‒30(35)× 22‒34(38) mm. Anthers and stigma-lobes 3‒10 mm long; stigma lobes spreading between anthers. Capsules green, red-striped and red-punctulated when young with numerous glandular hairs; teeth short, about 2 mm long, obtuse to somewhat emarginate.

Seeds of the colour between dark brown and black; 1.1‒2.2 mm long, 0.4‒1.7 mm thick, 0.4‒1.5 mm high ( Rostański et al. 1989, 2010).

Similar taxa: — Oenothera fallax most closely resembles one of its parent— O. glazioviana , mostly by its large flowers, red-striped flower buds and red-coloured papillae covering the plant. However, the flowers of O. fallax are much smaller, with a relatively short style and stamens hidden among the anthers. Moreover, O. fallax is similar to O. fallacoides Soldano & Rostański ( Soldano 1983: 128) , which, according to authors of the name, differs largely by red-coloured external surface of the bracts ( Soldano 1983).

Origin: —Arisen in Europe, as a hybrid resulting from a cross O. glazioviana × O. biennis ( Renner 1917, Rostański 1965).

Note: —In the articles concerning genetics of Oenothera , especially the early ones (e.g. de Vries 1901 –03, MacDougal et al. 1907, Priestley 1985), O. glazioviana was usually given as O. erythrosepala Borbás (1903: 245) or O. lamarckiana auct. genet. non Seringe ex De Candolle (1828: 47).

Genetic features: —Haploid genome combination: velans [from O. glazioviana ]— rubens [from O. biennis ] ( Rostański 1965); 2n=14 ( Przywara & Rostański 1980), during the first meiotic division chromosome form a ring of 12 and one bivalent ( Dietrich et al. 1997).

Biology: —Biennial, true-breeding,unlike the hybrid resulting from a reciprocal cross[ O. biennis × O. glazioviana ]; autogamous, permanent translocation hybrid (PTH) ( Rostański & Karlsson 2010).

Distribution: —Grown for ornament since the middle of 19 th century, often with O. glazioviana , also spontaneously formed in nature ( Rostański & Karlsson 2010). Formally the species was described from Germany ( Renner 1917), later it was observed in Wrocław, Western Poland ( Rostański 1965). Currently, the species is widespread in Europe, especially in North, Central and East part of the continent ( Rostański et al. 2010), although single localities were also reported from Asia as far as Japan (GBIF, occurrence not confirmed by a specialist).

Habitats: —As most evening primroses, O. fallax is usually found in disturbed habitats, roadsides, ruderal grasslands and wastelands ( Rostański & Karlsson 2010).

Flowering time: —From June to October ( Rostański 1963).

Hybrids: —According to Rostański (1982), Oenothera fallax hybridises with O. biennis and O. glazioviana (formally those are backcrosses), as well as with O. cambrica Rostański (1977: 285) in both directions. Moreover, hybrid offspring originated via crossing with O. victorinii Gates & Catcheside (in Gates 1933: 182) as male parent was described as a hybridigenous species— O. moravica V. Jehlík & Rostański (1995: 440) , whereas O. × hassica Rostański & Schnedler nom. prov. (1991) probably resulted from a cross O. fallax × O. pycnocarpa . Recently, hybrids of O. fallax with O. deflexa Gates (1936: 332) and O. casimiri Rostański in Rostański et al. (2004: 21) were also reported ( Hassler 2019).

Taxonomic status: —According to the representatives of the American school of taxonomy, O. fallax is treated as a hybrid with no formal rank ( Dietrich et al. 1997). In contrast, European taxonomists consider O. fallax as one of many well-established, hybrid-originated species ( Hudziok 1968, Soldano 1983, Jehlík 1993, Woźniak 2009, Rostański et al. 2010). Based on its morphology, the species was initially assigned to the section Oenothera ( Rostański 1965) , which later was transformed into the series Oenothera ( Rostański 1985) .

Variability: —Two morphological variants differing by the colour of the midribs were recognized by Rostański, however only one name ( O. fallax f. rubrinervis ) was validly published. Moreover, in the literature one may find two provisional names referring to intraspecific variability of the considered species, O. fallax var. rugosa ( Hassler 2019) and O. fallax f. brevihypanthialis Rostański ( Woźniak 2009, Hassler 2019).

Figures

FIGURE 1. Epitype of Oenothera fallax Renner—sheet 1 of 2 (WRSL).

FIGURE 2. Epitype of Oenothera fallax Renner—sheet 2 of 2 (WRSL).

FIGURE 3. The lower part of stem of Oenothera fallax Renner; crinkled leaves are clearly visible (phot. M. Woźniak-Chodacka).

FIGURE 4. Rhachis of Oenothera fallax Renner covered with red-coloured papillae (phot. M. Woźniak-Chodacka).

FIGURE 5. Red-striped flower buds and large flowers of Oenothera fallax Renner (phot. M. Woźniak-Chodacka).