Al Schneider's Rocky Mountains Plant Descriptions

Yellow Evening Primrose
Oenothera flava
Evening-Primrose family (Onagraceae)

Oenothera flava flowers are 2-4 inches across and so bright that they always catch attention. The long pink flower tube is usually overlooked. Flowers open late in the day and wilt to a gnarled pink mass early the next day. Oenothera flava likes moist areas and it grows there with an abundance of dark green, wavy-edged leaves. Linnaeus named this in 1753 using a name given several thousand years ago by Theophrastus to another in this family. "Flava" is Latin for "yellow." Marcus Jones collected the first specimen of this plant for science in 1894 in Utah.


©2004 Steve Matson

Description

without stem, from , sometimes spreading by rootstock. , 2-12" long, 1/8 to 2" wide, nearly or more commonly or , hairy to almost . Flower solitary in leaf axils, long lasting. Petals to 2" long, yellow, fading red orange to bronze or pink. a to over 1" long, .

Field Marks

Large of long, straight leaves topped by very large, showy yellow flower.

© Al Schneider

basal -- at the base, situated or attached at the base.

An entire leaf has smooth edges. Not toothed or lobed.

A perennial plant lives and blooms for many years.

pinnatifid -- A leaf shape that is pinnately lobed but not cut all the way to the axis.

A herb is a plant whose stems die back to the ground in the winter.

capsule -- a type of simple, dry fruit produced by many species of flowering plants. In most cases the capsule splits apart to release seeds.

taproot -- The primary decending root of a plant.

Like the teeth on a saw, leaves and other surfaces can have toothed edges.

fruit -- any seed-bearing structure in flowering plants. It is formed from the ovary after flowering.

basal leaves -- a leaf that grows lowest on the stem of a plant.

genus -- A subdivision of a botanical Family in which all members have a significant number of similar characteristics.

wing -- A maple seed has wings.

glabrous -- smooth, glossy, having no bristles or hair-like structures. Bald.

rosette -- usually a dense cluster of leaves at the base of a plant.