OregonFlora: Euphorbia glyptosperma vs. Euphorbia myrsinites

	Chamaesyce glyptosperma (synonym of Euphorbia glyptosperma)	Euphorbia myrsinites
	currugate-seeded spurge, ribseed sandmat, ridge-seeded spurge	myrtle spurge
Habit	Plants annual; stems prostrate, 4–40 cm, glabrous; taprooted.	Herbs perennial, 1–4 dm; stems decumbent to ascending, glabrous.
Leaves	oblanceolate to elliptic or ovate, 3–10 mm, occasionally with central red spot; margins entire to shallowly toothed; tips rounded; surfaces glabrous; petioles 0.3–1 mm; stipules linear, often dissected, 1–1.5 mm.	alternate (upper and floral leaves may be opposite or whorled), densely crowded on stem, obovate to obovate-oblong, 10–45 × 5–16 mm; margins entire to serrulate at least in upper 25%; tips mucronate; surfaces glabrous, glaucous;
Inflorescences	involucres 0.5–1 mm, glabrous; glands elliptic; gland appendages white.	involucres cone- to bell-shaped, 1.5–3 mm; glands shortly 2-horned.
Fruits	ovoid, 1.5–2 mm, glabrous.	round to oblong, 5–7mm.
Seeds	ovoid, 1–1.5 mm; cross-ridged.	round to oblong, 3–4 mm; smooth or wrinkled.
±		sessile.

	Chamaesyce glyptosperma	Euphorbia myrsinites
Distribution	[WildflowerSearch map] [BONAP county map]	[WildflowerSearch map] [BONAP county map]
Discussion	Dry areas, roadsides. Flowering Jun–Sep. 0–1600 m. BW, Col, ECas, Lava, Owy, Sisk, WV. CA, ID, NV, WA; southern Canada and most of US except southeastern states, Mexico. Native.	Disturbed areas, escaped from nearby cultivation. Flowering Apr–Jun. 500–1000 m. BW, Col, Lava. CA, ID, WA; scattered in western US, MI, Ontario; Europe. Exotic. The densely crowded leaves on the stems and decumbent to ascending habit easily distinguish E. myrsinites from all other members of this genus in Oregon.
Source	Flora of Oregon, volume 2, page 643 Stephen Meyers	Flora of Oregon, volume 2, page 645 Stephen Meyers
Sibling taxa	C. glyptosperma, C. maculata, C. prostrata, C. serpens, C. serpillifolia	E. crenulata, E. cyparissias, E. dentata, E. esula, E. helioscopia, E. lathyris, E. oblongata, E. peplus, E. spathulata
Synonyms	Euphorbia glyptosperma
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 WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Chamaesyce glyptosperma

(synonym of Euphorbia glyptosperma)

Euphorbia myrsinites

currugate-seeded spurge, ribseed sandmat, ridge-seeded spurge

myrtle spurge

Habit

Plants annual; stems prostrate, 4–40 cm, glabrous; taprooted.

Herbs perennial, 1–4 dm; stems decumbent to ascending, glabrous.

Leaves

oblanceolate to elliptic or ovate, 3–10 mm, occasionally with central red spot;

margins entire to shallowly toothed;

tips rounded;

surfaces glabrous;

petioles 0.3–1 mm;

stipules linear, often dissected, 1–1.5 mm.

alternate (upper and floral leaves may be opposite or whorled), densely crowded on stem, obovate to obovate-oblong, 10–45 × 5–16 mm;

margins entire to serrulate at least in upper 25%;

tips mucronate;

surfaces glabrous, glaucous;

Inflorescences

involucres 0.5–1 mm, glabrous;

glands elliptic;

gland appendages white.

involucres cone- to bell-shaped, 1.5–3 mm;

glands shortly 2-horned.

Fruits

ovoid, 1.5–2 mm, glabrous.

round to oblong, 5–7mm.

Seeds

ovoid, 1–1.5 mm; cross-ridged.

round to oblong, 3–4 mm; smooth or wrinkled.

sessile.

Chamaesyce glyptosperma

Euphorbia myrsinites

Distribution

[WildflowerSearch map]

[BONAP county map]

[WildflowerSearch map]

[BONAP county map]

Discussion

Dry areas, roadsides. Flowering Jun–Sep. 0–1600 m. BW, Col, ECas, Lava, Owy, Sisk, WV. CA, ID, NV, WA; southern Canada and most of US except southeastern states, Mexico. Native.

Disturbed areas, escaped from nearby cultivation. Flowering Apr–Jun. 500–1000 m. BW, Col, Lava. CA, ID, WA; scattered in western US, MI, Ontario; Europe. Exotic.

The densely crowded leaves on the stems and decumbent to ascending habit easily distinguish E. myrsinites from all other members of this genus in Oregon.

Source

Flora of Oregon, volume 2, page 643
Stephen Meyers

Flora of Oregon, volume 2, page 645
Stephen Meyers

Sibling taxa

C. glyptosperma, C. maculata, C. prostrata, C. serpens, C. serpillifolia