Burke: Oenothera curtiflora vs. Oenothera biennis

	Oenothera curtiflora	Oenothera biennis
	small-flowered gaura, velvet weed, velvetweed	King's-cureall, common evening primrose
Habit	Annual from a taproot, the stem single, simple below and branched above, 0.2-2 m. tall, puberulent, but also with soft, spreading hairs 2 mm. long.	Grayish biennial or short-lived perennial, the stems 3-10 dm. tall, erect, simple or freely-branching, with short, appressed hairs and longer, spreading, reddish-based hairs.
Leaves	Leaves alternate, the basal leaves spatulate, the lower cauline leaves oblong, the others oblong-lanceolate to lanceolate, 4-15 cm. long, entire to wavy-dentate, gradually reduced upward to very small, linear floral bracts.	Leaves alternate, the lower leaves petiolate, the upper sub-sessile, lanceolate, 1-2.5 cm. broad, entire to wavy-dentate.
Flowers	Inflorescence of many-flowered spikes, 1-3 dm. long; calyx tube very slender, 2-3 mm. long, with 4 distinct, reflexed lobes 2-3 mm. long; petals 4, short-clawed, pinkish, 2 mm. long; stamens 8, filaments without basal scales; ovary inferior, 4-celled.	Inflorescence an elongate spike, the buds erect, with bracts more or less the length of the capsules; calyx tube 3-5 cm. long, the 4 lobes 10-15 mm. long, reflexed, distinct; petals 4, yellow, 1-2 cm. long; stamens 8, equal to the petals and style; stigma with 4 linear lobes 4-7 mm. long; ovary inferior, 4-celled.
Fruits	Fruit hardened, 6-10 mm. long, spindle-shaped, glabrous, 4-angled by not winged.	Capsule 2.5-4 cm. long, linear, cylindrical.

	Oenothera curtiflora	Oenothera biennis
Flowering time	June-September	June-August
Habitat	Meadows, stream banks, roadsides, sandy or rocky slopes, often where disturbed.	Meadows and stream banks, from the plains to the lower mountains, typically where disturbed.
Distribution	Occurring east of the Cascades crest in Washington; south-central Washington to eastern Oregon, Nevada, and Arizona, east to North Dakota,, Iowa, and Louisiana; introduced in California and the eastern U.S., South America, Asia, and Australia. [WildflowerSearch map] [BONAP county map]	Occurring on both sides of the Cascades crest in Washington; widely distributed throughout much of North America. [WildflowerSearch map] [BONAP county map]
Origin	Introduced from the central U.S.	Introduced from Europe
Conservation status	Not of concern	Not of concern
Sibling taxa	O. biennis, O. cespitosa, O. elata, O. flava, O. glazioviana, O. pallida, O. suffrutescens	O. cespitosa, O. curtiflora, O. elata, O. flava, O. glazioviana, O. pallida, O. suffrutescens
Web links	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria, Turner Photog. WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Oenothera biennis

small-flowered gaura, velvet weed, velvetweed

King's-cureall, common evening primrose

Habit

Annual from a taproot, the stem single, simple below and branched above, 0.2-2 m. tall, puberulent, but also with soft, spreading hairs 2 mm. long.

Grayish biennial or short-lived perennial, the stems 3-10 dm. tall, erect, simple or freely-branching, with short, appressed hairs and longer, spreading, reddish-based hairs.

Leaves

Leaves alternate, the basal leaves spatulate, the lower cauline leaves oblong, the others oblong-lanceolate to lanceolate, 4-15 cm. long, entire to wavy-dentate, gradually reduced upward to very small, linear floral bracts.

Leaves alternate, the lower leaves petiolate, the upper sub-sessile, lanceolate, 1-2.5 cm. broad, entire to wavy-dentate.

Flowers

Inflorescence of many-flowered spikes, 1-3 dm. long;

calyx tube very slender, 2-3 mm. long, with 4 distinct, reflexed lobes 2-3 mm. long;

petals 4, short-clawed, pinkish, 2 mm. long;

stamens 8, filaments without basal scales;

ovary inferior, 4-celled.

Inflorescence an elongate spike, the buds erect, with bracts more or less the length of the capsules;

calyx tube 3-5 cm. long, the 4 lobes 10-15 mm. long, reflexed, distinct;

petals 4, yellow, 1-2 cm. long;

stamens 8, equal to the petals and style;

stigma with 4 linear lobes 4-7 mm. long;

ovary inferior, 4-celled.

Fruits

Fruit hardened, 6-10 mm. long, spindle-shaped, glabrous, 4-angled by not winged.

Capsule 2.5-4 cm. long, linear, cylindrical.

Oenothera curtiflora

Oenothera biennis

Flowering time

June-September

June-August

Habitat

Meadows, stream banks, roadsides, sandy or rocky slopes, often where disturbed.

Meadows and stream banks, from the plains to the lower mountains, typically where disturbed.

Distribution

Occurring east of the Cascades crest in Washington; south-central Washington to eastern Oregon, Nevada, and Arizona, east to North Dakota,, Iowa, and Louisiana; introduced in California and the eastern U.S., South America, Asia, and Australia.

[WildflowerSearch map]

[BONAP county map]