Notes on Oenothera and list of the species of Texas

Here is some information on the Oenothera species of the Llano Estacado.
BONAP

[DRAFT! -
The erect members of sect. Oenothera and the members of sect. Anogra have not been given characteristics to distinguish. Also, I hope to add some more links and maybe photos to the individual species. However, I figure it's better to make this available now so people can review the same document as I am as I ID the members of Oenothera. Just remember that this is a draft, and I will be updating this as I learn more and have time to add more. Lastly, there are species I haven't filled in as much as I want to. Keep this in mind as you use this and let me know if there's a specific species you're having trouble with that isn't really specific enough in the descriptions provided here.]

Sect. Calylophus

Oenothera capillifolia (Calylophus capillifolia; C. berlandieri) - Buds strongly 4-angled, keeled at sepal margins; leaves serrated. Styles long, stigmas held to the apices of the outer series of anthers or beyond; petals trending slightly larger than O. serrulata. Widespread mostly in sandy soils.

Oenothera capillifolia subsp. berlandieri (Calylophus berlandieri subsp. berlandieri) - Plants multistemmed, spreading, sometimes shrubby perennials; flower throat and stigmas never black. Widespread in sandy soils.

Oenothera capillifolia subsp. capillifolia (Calylophus berlandieri subsp. pinifolia; Calylophus capillifolia) - Plants single or few-stemmed annuals to short-lived perennials; flower throats and stigmas yellow or black. If pressent on the Llano Estacado, restricted to the eastern margins, probably absent on the High Plains.

Oenothera gayleana - Buds strongly 4-angled, keeled at sepal margins. Gypsum in Trans-Pecos and north Rolling Plains region; probably absent on the High Plains.

Oenothera serrulata (Calylophus serrulata) - Buds strongly 4-angled, keeled at sepal margins; leaves serrated. Styles short, stigmas held to the apices of the inner series of anthers at most; petals trending slightly smaller than O. capillifolia. Present; details not yet available. After considerable searching on iNaturalist, I have found maybe 2 or 3 observations with this style characteristic. Also, the style characteristic seems somewhat variable and inconsistent in individual plants (perhaps even to the point of calling the flowers heteromorphic). However, there are no other characters from the treatments that I've read that can be relied upon (petal length has more overlap than not). Furthermore, O. capillifolia subsp. capillifolia often has very short anthers and short styles (the morphotype that appears annual and without black stigma or floral tube). There is a lot of complexity in this group and I'm not really sure how to make sense of it at present other than to mark those with the key characteristic as O. serrulata even if the taxonomic support for that is poor. I'll keep looking for more information. Here are the observations I'm referencing: plant like O. capillifolia subsp. berlandieri with strongly heteromorphic styles (due to genetics or aberrance, I'm not sure); the most reliably short-styled plant I've found; and styles short, but heteromorphic, anthers short, probably O. capillifolia subsp. capillifolia based on habit and short anthers unless I am misinterpreting one of the concepts.

Oenothera hartwegii (Calylophus hartwegii) - Buds mostly rounded, sepal margins not keeled. Plants perennial; vestiture various: if ovaries grey from dense covering of hairs, hairs throughout plant spreading. Widespread.

Oenothera hartwegii subsp. fendleri (Calylophus hartwegii var. fendleri) - Plants glabrous. Northern High Plains region and Trans-Pecos mountains.

Oenothera hartwegii subsp. filifolia (Calylophus hartwegii var. filifolia) - Plants with glandular hairs; leaves filiform to narrowly lanceolate. Mostly restricted to gypsum or alkali soils, sometimes limestone.

Oenothera hartwegii subsp. hartwegii (Calylophus hartwegii var. hartwegii) - Plants various with sparse glandular hairs and non-glandular hairs; leaves linear to narrowly lanceolate. Primarily stabalized sands and calcareous outcrops.

Oenothera hartwegii subsp. pubescens (Calylophus hartwegii var. pubescens) - Plants generally densely hairy with spreading hairs; leaf bases abruptly truncate. Primarily calcareous outcrops, most prominent subspecies around Lubbock and north.

Oenothera lavandulifolia (Calylophus lavandulifolia) - Buds mostly rounded, sepal margins not keeled. Plants perennial, not viscid; ovaries densely grey hairy with appressed hairs. Widespread, but most prominent in rocky calcareous soils along breaks and draws.

Oenothera tubicula (Calylophus tubicula) - Buds mostly rounded, sepal margins not keeled. Plants annual, viscid from abundance of glandular hairs. Mostly in counties south of Andrews Co. in limestone or other calcareous soils.

Sect. Gaura

Oenothera calcicola (Gaura calcicola) - Plants essentially glabrous, not rhizomatous; flowers medium; fruits with long stipe. Seems to prefer limestone. Illustration of fruit.
Representative observations: flowers, leaves; fruits, plant

Oenothera cinerea var. cinerea (Gaura cinerea) - Plants densely hairy, usually with appressed hairs, but may be unappressed; flowers medium; fruits with long stipe. Plants of sandy soils. Illustration of fruit.
Representative observations: rosette and leaf hairs; flowers, fruits, habit, and leaf hairs

Oenothera curtiflora (Gaura parviflora) - Plants densely hairy with soft, villous hairs; flowers very small; fruits without a long stipe, not deeply lobed, not significantly larger at the base. Plants of disturbed, primarily wet soils including waste places and roadsides. Illustration of fruit.
Representative observations: most characteristics; rosette; flowers and fruits

Oenothera lindheimeri (Gaura lindheimeri) - Plants essentially glabrous; flowers large; fruits without long stipe, not significantly enlarged at the base, widest point toward the middle. E TX; commonly cultivated. Illustration of fruit.

Oenothera neallyi (Gaura suffulta var. neallyi) - Plants with sparse, long, straight hairs below inflorescence, glandular hairs above inflorescence; flowers large; fruits without stipe, greatly lobed and enlarged at the base. Mostly Trans-Pecos TX; may occur in southern Llano Estacado. Illustration of fruit.

Oenothera sinuosa (Gaura sinuata) - Plants essentially glabrous, rhizomatous; flowers medium; fruits with long stipe. Most of TX, possibly eastern Llano Estacado. Illustration of fruit.
Representative observations: habit

Oenothera suffrutescens (Gaura coccinea) - Plants usually with many gray, appressed hairs, rhizomatous; flowers medium or slightly smaller; fruits with thickened stipe, widest at base. Common and widespread in various habitats and soils. Illustration of fruit.
Representative observations: rosette; leaves and stem hairs; flowers, fruit, and mature habit

Oenothera suffulta (Gaura suffulta) - Plants with sparse, long, straight hairs below inflorescence, glabrous above inflorescence; flowers large; fruits without stipe, greatly lobed and enlarged at the base. Common in various disturbed soils including roadsides. Illustration of fruit.
Representative observations: rosette; habit; flowers, mature fruit

Oenothera triangulata (Gaura triangulata) - Plants with sparse, long, straight hairs below inflorescence, glabrous above inflorescence; flowers appear medium, most flowers 3-merous (3 petals, sepals, and stigmas; 6 stamens) instead of the usual 4-merous; fruits without stipe, greatly lobed and enlarged at the base. Rolling and Lubbock area of High Plains. Illustration of fruit. Representative observations: flower.

Oenothera xenogaura (Gaura drummondii) - Plants densely appressed hairy, rhizomatous; fruits without or with very short stipe, greatly lobed and enlarged at the base. Most TX except High Plains and Trans-Pecos, likely not on Llano Estacado. Illustration of fruit.

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Other species of Texas:

Oenothera arida (Gaura macrocarpa) - Restricted to the Trans-Pecos. Illustration of fruit.
Oenothera boquillensis (Gaura boquillensis) - Restricted to the Trans-Pecos along Rio Grande. Illustration of fruit.
Oenothera cinerea var. parksii (Gaura cinerea) - Illustration of fruit.
Oenothera demareei (Gaura demareei) - Far E TX. Illustration of fruit.
Oenothera filiformis (Gaura longiflora) - East and South TX. Illustration of fruit.
Oenothera hexandra var. gracilis (Gaura hexandra var. gracilis) - Trans-Pecos. Illustration of fruit.
Oenothera hexandra var. hexandra (Gaura hexandra var. hexandra) - Trans-Pecos; Chinati Peak. Illustration of fruit.
Oenothera mckelveyae (Gaura mckelveyae) - S TX. Illustration of fruit.
Oenothera patriciae (Gaura brachycarpa) - E half to 2/3rds of TX. Illustration of fruit.

Subsect. Stenosiphon

Oenothera glaucifolia (Stenosiphon liniflorus) - Flowers actinomorphic, white. Illustration of fruit.

Oenothera s.s. (multiple sections)

Oenothera albicaulis (Sect. Kleinia) - Caulescent annual, stems spreading; flowers white; fruits cylindroid. Differs from O. engelmannii by many characteristics including: appressed hairs, habit, habitat, and leaf shape (comparison here). Widespread, but not typically denser or rockier soils.

Oenothera caespitosa (Sect. Pachylophus) - Acaulescent perennial; flowers white. Guadelupe Mnts and far east NM in Roosevelt (maybe on west edge of Llano?).

Oenothera canescens (Sect. Gauropsis) - Caulescent perennial, stems spreading; flowers pink; fruits ovoid. Mostly playa basins of Lubbock Co. and north.

Oenothera coronipifolia (Sect. Kleinia) - Caulescent perennial, stems upright; flowers white; fruits cylindroid. NM to Roosevelt County (possibly Llano Estacado).

Oenothera coryi (Sect. Megapterium) - Acaulescent perennial; flowers yellow. Differs from O. howardii and O. macrocarpa by its linear leaves. Restricted to NE Llano Estacado into Rolling Plains region (rare).

Oenothera elata (Sect. Oenothera) - Caulescent biennial, stems erect; flowers yellow; fruits cylindroid. Trans-Pecos, E TX, and one county from NW Edwards Plateau.

Oenothera engelmannii (Sect. Anogra) - Caulescent annual, stems spreading; flowers white; fruits cylindroid. Differs from O. albicaulis by many characteristics including: many long pilose (spreading) hairs, more robust stems, habit, habitat, and leaf shape (comparison here). Sandy soils, especially disturbed dune habitat that was historically stable and adjacent areas; somewhat widespread but especially the southern counties.

Oenothera grandis (Sect. Oenothera) - Caulescent annual, stems spreading; flowers yellow; fruits cylindroid. Differs from O. laciniata by its much larger flowers (to larger than halfdollar-size vs. to quarter-size or smaller). Widespread but particularly likes disturbed, non-clay, non-calcareous soils.

Oenothera heterophylla (Sect. Oenothera) - Syn. O. cordata. Caulescent biennial, stems erect; flowers yellow; fruits cylindroid. Reported for counties a little southeast, likely absent.

Oenothera howardii (Sect. Megapterium) - Acaulescent perennial; flowers yellow; fruits. Differs from O. coryi by its non-linear leaves; differs from O. macrocarpa by being acaulis and having much smaller fruits imbedded in rosettes. Mostly Trans-Pecos, but also reported from Sweetwater area and NE Llano Estacado; may be absent.

Oenothera jamesii (Sect. Oenothera) - Caulescent biennial; flowers yellow; fruits cylindroid. E Llano Estacado.

Oenothera kunthiana (Sect. Leucocoryne) - Caulescent annual, stems spreading; flowers white; fruits clavate with narrow stipe. S Llano Estacado in limestone.

Oenothera laciniata (Sect. Oenothera) - Caulescent annual, stems spreading; flowers yellow; fruits cylindroid. Differs from O. grandis by its much smaller flowers (to quarter-size or smaller vs. to larger than halfdollar-size). Disturbed soils, potentially widespread but probably more restricted to urban areas.

Oenothera macrocarpa (Sect. Megapterium) - Caulescent or acaulescent perennial, stems upright; flowers yellow; fruits very large and winged. Lubbock Co. and North.

Oenothera neomexicana (Sect. Anogra) - NM including far SE NM.

Oenothera pallida (Sect. Anogra) - Trans-Pecos and far N TX.

Oenothera rhombipetala (Sect. Oenothera) - Caulescent biennial; flowers yellow; fruits cylindroid. Petals acute. Sandy soils in the southern and eastern counties.

Oenothera speciosa (Sect. Hartmannia) - Caulescent rhizomatous perennial, stems upright; flowers pink or white; fruits clavate with narrow stipe. Probably naturalized through much of the Llano where it is present from cultivated plants; potentially some native in the southernmost counties; found predominantly in riparian areas, especially draws.

Oenothera triloba (Sect. Lavauxia) - Acaulescent annual; flowers yellow. Widespread in calcareous soils.

Oenothera villosa (Sect. Oenothera) - Caulescent biennial; flowers yellow; fruits cylindroid. E and far N TX; probably absent.

Oenothera groups:

Plants acaulescent; flowers white:
Pachylophus
Plants acaulescent (O. macrocarpa often short caulescent); flowers yellow:
Megapterium: Perennials (Information here and here)
Lavauxia: Annuals
Plants caulescent; fruits clavate with narrow stipe (stalk-like structure); flowers white or pink:
Hartmannia: Perennials
Leucocoryne: Annuals
Plants caulescent; fruits ovoid; flowers white or pink:
Paradoxus: Flowers and plants large; hypanthium 40-55 mm long; petals 15-30 mm long
Gauropsis: Flowers and plants small; hypanthium 5-15 mm long; petals 8-12 mm long
Plants caulescent; fruits cylindric; flowers white (fading pink):
Kleinia
Anogra
Plants caulescent; fruits cylindric; flowers yellow:
Oenothera: Two forms, spreading stems & erect stems

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Other species of Texas:

Oenothera drummondii - Mostly coastal TX.
Oenothera falfurriae - S TX.
Oenothera flava - NM (maybe Trans-Pecos are far N TX?).
Oenothera havardii (Sect. Paradoxus) - Trans-Pecos, N Presidio and Brewster Co.
Oenothera linifolia - East third of TX.
Oenothera mexicana - S TX.
Oenothera pilosella - Far E TX if in TX.
Oenothera primiveris - Trans-Pecos.
Oenothera pubescens - Trans-Pecos.
Oenothera rosea (Sect. Hartmannia) - Trans-Pecos and S TX.
Oenothera spachiana - E third of TX.
Oenothera tetraptera (Sect. Leucocoryne) - S TX.
Oenothera texensis (Sect. Hartmannia) - Davis Mountains.

Sources:
A Revision of the Genus Gaura.
Images of Herbarium Specimens of Travis County Plant Species: Family Onagraceae (Plant Resources Center, University of Texas at Austin).
Manual of the Vascular Plants of Texas (Correll and Johnston 1970).
Flowering Plants of Trans-Pecos Texas and Adjacent Areas (Powell and Worthington, 2018).
Taxonomic changes in Oenothera sections Gaura and Calylophus (Onagraceae).
Oenothera gayleana (Oenothera sect. Calylophus, Onagraceae), a new gypsophile from Texas, New Mexico, and Oklahoma .
Shinners and Mahler's Illustrated Flora of North Central Texas.

Posted by nathantaylor nathantaylor, September 15, 2019 20:48

Comments

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@amzapp @ellen5 It's far from polished, but you might find it helpful.

Posted by nathantaylor 5 months ago (Flag)
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I know THAT was a lot of work! Well done Nathan! I love these species key posts!

Posted by kimberlietx 5 months ago (Flag)
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Thanks!

Posted by nathantaylor 5 months ago (Flag)
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Excellent!

Posted by troney 5 months ago (Flag)

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