OregonFlora: Euphorbia lathyris vs. Euphorbiaceae

	Euphorbia lathyris	Euphorbiaceae
	caper spurge, gopher plant, mole plant	spurge family
Habit	Herbs or subshrubs biennial, 1.5–12 dm; stems erect, glabrous, glaucous.	Shrubs, subshrubs, or herbs annual, biennial, or perennial, monoecious or dioecious; stems branched.
Leaves	opposite, narrowly oblong to ovate or subcordate, 30–150 × 5–30 mm, bases clasping; margins entire; tips acute; surfaces glabrous.	alternate, subopposite; opposite or whorled; simple; margins entire or toothed; petioles present or not; stipules present or not.
Inflorescences	involucres bell-shaped, 2.5–4 mm; glands 2-horned; horns rounded and short.	various and diverse; in some genera individual flowers reduced and grouped into a bisexual inflorescence resembling a single flower (cyathium); bracts present or not, sometimes petaloid in appearance.
Flowers		unisexual, sometimes with a corolla-like involucre; sepals 0–5; petals usually 0; stamens 1–many; ovaries superior; styles 3.
Fruits	spherical, 5–15 mm.	capsules; dry.
Seeds	round, 4–6 mm, wrinkled or with shallow reticulate markings.	1 per chamber.

	Euphorbia lathyris	Euphorbiaceae
Distribution	[WildflowerSearch map] [BONAP county map]	[BONAP county map]
Discussion	Disturbed areas. Flowering May–Jul. 0–500 m. Col, CR, Est, Sisk, WV. CA, ID, WA; scattered across North America; Asia, Europe. Exotic. Euphorbia lathyris is our only member of the genus to have only opposite leaves. It is sometimes planted in gardens based on the unsubstantiated belief it may deter moles and gophers.	Worldwide. ~300 genera; 3 genera treated in Flora. Mercurialis annua has been collected on ballast in Portland and rarely as a garden waif. The plants and seeds of many species in Euphorbiaceae are toxic and highly poisonous to animals. The milky sap of Chamaesyce and Euphorbia species contains chemicals that help protect the plants from herbivory and can be very irritating to skin and eyes.
Source	Flora of Oregon, volume 2, page 645 Stephen Meyers	Flora of Oregon, volume 2, page 642
Sibling taxa	E. crenulata, E. cyparissias, E. dentata, E. esula, E. helioscopia, E. myrsinites, E. oblongata, E. peplus, E. spathulata
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: CA, OR Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Euphorbiaceae

caper spurge, gopher plant, mole plant

spurge family

Habit

Herbs or subshrubs biennial, 1.5–12 dm; stems erect, glabrous, glaucous.

Shrubs, subshrubs, or herbs annual, biennial, or perennial, monoecious or dioecious; stems branched.

Leaves

opposite, narrowly oblong to ovate or subcordate, 30–150 × 5–30 mm, bases clasping;

margins entire;

tips acute;

surfaces glabrous.

alternate, subopposite; opposite or whorled; simple;

margins entire or toothed;

petioles present or not;

stipules present or not.

Inflorescences

involucres bell-shaped, 2.5–4 mm;

glands 2-horned; horns rounded and short.

various and diverse; in some genera individual flowers reduced and grouped into a bisexual inflorescence resembling a single flower (cyathium);

bracts present or not, sometimes petaloid in appearance.

Flowers

unisexual, sometimes with a corolla-like involucre;

sepals 0–5;

petals usually 0;

stamens 1–many;

ovaries superior;

styles 3.

Fruits

spherical, 5–15 mm.

capsules; dry.

Seeds

round, 4–6 mm, wrinkled or with shallow reticulate markings.

1 per chamber.

Euphorbiaceae

Distribution

[WildflowerSearch map]

[BONAP county map]

Discussion

Disturbed areas. Flowering May–Jul. 0–500 m. Col, CR, Est, Sisk, WV. CA, ID, WA; scattered across North America; Asia, Europe. Exotic.

Euphorbia lathyris is our only member of the genus to have only opposite leaves. It is sometimes planted in gardens based on the unsubstantiated belief it may deter moles and gophers.

Worldwide. ~300 genera; 3 genera treated in Flora.

Mercurialis annua has been collected on ballast in Portland and rarely as a garden waif. The plants and seeds of many species in Euphorbiaceae are toxic and highly poisonous to animals. The milky sap of Chamaesyce and Euphorbia species contains chemicals that help protect the plants from herbivory and can be very irritating to skin and eyes.

Source

Flora of Oregon, volume 2, page 645
Stephen Meyers

Flora of Oregon, volume 2, page 642

Sibling taxa