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Oenothera organensis
(Organ Mountains evening primrose)

[taxon report][distribution map][all photos][line drawing]

Family: Onagraceae

Scientific Name: Oenothera organensis Munz

Synonyms: Oenothera macrosiphon Wooton & Standley

Vernacular Name: Organ Mountains evening primrose

R-E-D Code: 2-1-3

Description: Perennial herb; stems spreading to prostrate, about 60 cm long; herbage rough-hairy; leaves lance-shaped, petioles short-winged or petioles absent; flowers with a long tube and spreading petals, yellow, becoming deep red in age; petals 5-6 cm long; hypanthium tube beneath the petals very conspicuous and up to 19 cm long; ovary inferior; capsule 3-4 cm long, cylindrical but angled and slightly hairy. Flowers June through September.

Similar Species: Oenothera elata ssp. hookeri (= O. biennis var. hookeri, O. hookeri) is a tall, yellow-flowered species that grows in some of the same canyons as O. organensis. It is distinguished by erect stems, sharply angled seeds, and capsules that taper towards the apex versus the spreading stems, obtusely angled seeds, and enlarged capsule apices of O. organensis.

Distribution: New Mexico, Dona Ana County, Organ Mountains.

Habitat: Seeps, springs, and colluvium substrates in the bottom of drainages in montane scrub and piƱon-juniper-oak woodland; 1,700-2,280 m (5,700-7,600 ft).

Remarks: The species is endemic to the Organ Mountains of New Mexico. It occurs in many, but not all, of the canyons within the range. There is little genetic variability, but it is a self-incompatible obligate out-crosser. Pollinator species include the sphinx moth.

Conservation Considerations: It is a palatable species and livestock, if allowed, can both eat the above ground parts and disturb the roots through hoof action. However, there are few places within its range that are used for livestock grazing. Sediments routinely cover Oenothera organensis in the fall after seasonal downpours, with no serious effect. However, heavy scouring and massive sediment deposition could occur with rains that come after a significant fire in the watershed.

Important Literature (*Illustration):

*New Mexico Native Plants Protection Advisory Committee. 1984. A handbook of rare and endemic plants of New Mexico. University of New Mexico Press, Albuquerque.

*Dietrich, W., P.H. Raven and W.L. Wagner. 1985. Revision of Oenothera sect. Oenothera subsect. Emersonia (Onagraceae). Systematic Botany 10(1):29-48.

Levin, D.A., K. Ritter and N.C. Ellstrand. 1970. Protein polymorphism in the narrow endemic Oenothera organensis. Evolution 33:534-542.

Information Compiled By: Juanita A.R. Ladyman, 1998

Agency Status:
Taxon USFWS State of NM USFS BLM Navajo Nation Natural Heritage NM Global Rank
Oenothera organensisOenothera organensis...S2

Photo credits in header Peniocereus greggii var. greggii © T. Todsen,
Lepidospartum burgessii © M. Howard, Argemone pleiacantha ssp. pinnatisecta © R. Sivinski
©2005 New Mexico Rare Plant Technical Council