Close this window.

Oenothera dissecta

Distribution: Locally common in clay or sandy soils of arroyo banks or sometimes open flats, Acacia and Opuntia grasslands, Larrea scrub, in the Chihuahuan Desert from the vicinity of F. I. Madero, southeastern Durango to Zacatecas as far north as Concepcion del Oro, southwest San Luis Potosi and vicinity of Ojuelos, northern Jalisco, 1,800-2,400 m.

Habit: Leafy, compact to sprawling perennial herbs, producing adventitious shoots from spreading lateral roots, stems simple to branched, 0.2-30 (-80) cm long, weakly erect becoming decumbent, older stems woody, strigillose, the hairs 0.1-0.3(-0.4) mm long.

Leaves: Leaves in a basal rosette and cauline, rosette leaves oblanceolate, 2-6 cm long, 1-1.5 cm wide, less divided than cauline leaves, dentate, or pinnately lobed or with oblong lobes, usually deciduous before flowering, cauline leaves 2-8 cm long, 0.7-1.5 cm wide, lanceolate, sparsely to densely strigillose, the hairs evenly distributed, rarely more dense along veins and margins, sometimes also sparsely hirsute, these hairs 0.6-1.5 mm long and confined to veins and margins, irregularly pinnatifid, the lobes linear-oblong to linear, petioles on all leaves 0-1.5 cm long.

Flowers: Buds erect, oblong-lanceolate, with free sepal tips 1-6 mm long, flowers one rarely more per stem opening per day near sunset, ovary 11-16(-18) mm long, densely strigillose, sessile, floral tube (26-)35-42 mm long, flaring to 3-6 mm at the mouth, densely strigillose, glabrous within, sepals splitting along one suture and reflexed to one side as a unit at anthesis, 18-35 mm long, 2-3 mm wide, strigillose, the margins with a conspicuous purple stripe often flecked with purple spots, petals white, fading pink, drying purple, broadly obovate to nearly orbicular, (15-)20-40 mm long, (14-)17-36 mm wide, staminal filaments 10-17 mm long, anthers yellow, (6-)8-11 mm long, style (44-)47-70 mm long, stigma lobes (3-)5-6 mm long, well elevated above the anthers at anthesis.

Fruit: Capsule few, indehiscent, (9-)13-20 mm long, 3-5 mm in diameter (excluding wings), ovoid to narrowly ovoid, hard and leathery at maturity, abruptly constricted to a sterile beak 2-6 mm long, sometimes somewhat twisted, the base cuneate, dehiscing ca. 1/3 the capsule length, the valves with a median ridge, the margins of the valves with a wing 2-2.5 mm wide extending the length of the capsule, usually widest, above the middle, tapering to a pedicel-like, sterile basal portion 1-4 mm long.

Seeds: Seeds ca. 100-130(?) per capsule, clustered in several indefinite rows (apparently reduced to one row in mature capsules), narrowly ovoid, obscurely angled, light brown, ca. 1.5 mm long, ca. 0.6-0.8 mm wide, the surface glossy, obscurely reticulate, appearing finely granular, rather persistent on the placenta.

Chromosomes: Mitotic chromosome number: 2n = 28.

Notes: FNA, Self-compatible, but outcrossing.

Top

Close this window.