Oenothera nealleyi (J. M. Coulter) Krakos & W. L. Wagner, 2013

Wagner, Warren L., Krakos, Kyra N. & Hoch, Peter C., 2013, Taxonomic changes in Oenothera sections Gaura and Calylophus (Onagraceae), PhytoKeys 28, pp. 61-72 : 63

1. Oenothera nealleyi (J. M. Coulter) Krakos & W. L. Wagner comb. nov.

Basionym.

Gaura nealleyi J. M. Coulter, Contr. U.S. Natl. Herb. 1: 38. 1890. Gaura suffulta nealleyi (J. M. Coulter) P. H. Raven & Gregory, Mem. Torrey Bot. Club 23: 81. 1973 [ “1972”]. Oenothera suffulta (Engelmann ex A. Gray) W. L. Wagner & Hoch subsp. nealleyi (J. M. Coulter) W. L. Wagner & Hoch, Syst. Bot. Monogr. 83: 214. 2007.

Type.

United States. Texas: Presidio County, Chenate [Chinati] region, 1889, G. C. Nealley 545 [the species entry number (150) from Coulter’s publication also on sheet below 545] (Holotype: US-00015158!; isotype: F!).

Gaura suffulta Engelmann ex A. Gray var. terrellensis Munz, Bull. Torrey Bot. Club 65: 121. 1928.

Type: United States. Texas: Terrell County, Sanderson, 1 May 1934, V. L. Cory 8469 (Holotype: POM-200873; Isotype: TAES).

Annual from a stout taproot, usually branched from the base, 20-70 (-100) cm tall, villous proximally, the leaves subglabrous or sparsely villous along the veins and margins, becoming glandular puberulent in the distal portion of the plant, especially on the outside of the floral tube and the sepals. Leaves: rosette leaves lyrate, 3.5-9 × 0.5-1.5 cm, gradually narrowed to the petiole, cauline leaves 1.5-7 × 0.1-0.6 cm, narrowly lanceolate to linear, margin sinuate-dentate, undulate, subsessile. Flowers 4-merous, opening at sunset; floral tube 10-20 mm; sepals 11-21 mm; petals 10-15 mm; staminal filaments 8-13 mm, anthers 2-6 mm, pollen 90-100% fertile; style 22-36 mm. Capsule indehiscent, 4.5-8 × 2-5 mm, nut-like, hard, woody, not reflexed, the body ellipsoid or ovoid, broadly winged on the angles and deeply furrowed between the angles, lower angles or projections of the wings at or above the middle prominent; stipe 0.2-2.2 mm long. Seeds 3-4 (-5), 2-3 (-4) mm, ovoid, usually flattened on one or several sides by crowding in the fruit, yellowish to light brown. Gametic chromosome number: n = 7. Self-incompatible.

Phenology and distribution.

Flowering from April to October. Trans-Pecos Texas and northern Coahuila, Mexico, north to Bernalillo and Torrance counties, New Mexico, in washes and other sandy places, grasslands, and extending to pinyon-juniper woodlands; 1220-2140 m.

Raven and Gregory (1972) considered Oenothera nealleyi to represent an unevenly intergrading entity with Oenothera suffulta based on geographical merging of some of the characteristics that distinguish them and because the entity from Terrell County, Texas, described as Gaura suffulta var. terrellensis Munz has a combination of characteristics of the two taxa. The origin of these plants from Terrell County should be further explored. For now we here continue to include this name in the synonymy of Oenothera nealleyi . The molecular data ( Krakos 2011; unpubl.) suggest that Oenothera nealleyi is not as closely related to Oenothera suffulta as suggested by Raven and Gregory (1972), given the placement in the phylogeny and the difference in scent profiles for these two taxa. Oenothera suffulta is a member of a strongly supported clade ( Fig. 1 ) consisting of it along with Oenothera triangulata and Oenothera patriciae , while Oenothera nealleyi is a member of a polytomy that consists of other species of subsect. Gaura , with the Oenothera suffulta - Oenothera triangulata - Oenothera patriciae clade sister to it. Oenothera nealleyi has a strong sweet scent, characterized by benzaldehyde (almond), cinnamaldehyde, cinnamic alcohol (cinnamon), methyl salicylate and its methyl ether (wintergreen), neral and geranial (citronella), and nerol and geraniol (lemon) (R. Raguso, pers. comm.), whereas Oenothera suffulta does not have a discernible scent. This difference in scent probably plays a key role in the pollination syndromes for these species.

Figures

Figure 1. Portion of a Bayesian tree of Oenothera sect. Gaura within a larger analysis of one of two major clades of Oenothera, which has been referred to as clade B by Wagner et al. (2007) with several outgroup species of the other major clade (A) of Oenothera from Krakos et al. (unpubl.). The phylogeny is based on nuclear sequences of ITS and ETS and the chloroplast markers rps 16, ndh F, trn L-F, and rbcl. The labels use the most recent prior taxonomy, placing the group in Oenothera (Wagner et al. 2007), using the taxon delimitations of Raven and Gregory (1972). The taxa involved in the proposed changes here are in bold. Numbers above nodes indicate Bayesian posterior probability values.