Euphorbia glyptosperma (Ridge-Seeded Spurge) - photos and description

 

 

 


Stems with flowers in small clusters in leaf axils in above photo.

 


The fertilized ovary eventually straightens on its stem, rising above the cyathium.


Leaves opposite with few serrations.


Leaves can be somewhat sickle-shaped.

General: Prostrate, much-branched, matt-forming plants. Foliage when broken exudes a white sap, stems light red in colour. Plants glabrous.

Flowers: Pinkish-white in clusters of up to 5 flowers in leaf axils. The flowers are in a cup-shaped calyxlike involucre called a cyathium. The cyathium has 1 pistillate flower, several staminate flowers, and there are white, fringed, petal-like extensions at the top of the cyathium. Once fertilized, the pistillate flower swells, elongates, and hangs out of the side of the cyathium. We measured a cyathium at 2 mm long, and a fertilized ovary hanging outside the cyathium at 1.5 mm long.

Leaves: Opposite, oblong to somewhat falcate (sickle-shaped), asymmetrical with one side of the leaf longer than the other, rounded at base. The margins weakly serrulate, at least at the apex. We measured a leaf at 10 mm long by 4 mm wide.

Height: Not applicable, we've measured plants to a spread of 30 cm.

Habitat: Dry, sandy soil in waste places and yards. Can often be found growing in cracks in sidewalks and pavement.

Abundance: Common.

Origin: Native.

Similar species: This plant is very similar to Euphorbia serpyllifolia. That species has leaves which are more conspicuously serrulate, and sometimes has leaves with a purple splotch in the middle of the leaf.

In examining the two species in the herbarium, I observed the leaves of E. serpyllifolia are more serrulate. However, the difference is so small between these two plants that I think in the field it could be difficult to distinguish one species from the other based solely on the degree of serration of the leaves. To be confident in identifying E. serpyllifolia I'd prefer to have a plant with purple splotches on its leaves.

When and where photographed: Photos taken July 28th and August 9th, sandy gravel pit, Qu'Appelle Valley, about 150 km east of our home in Regina, SK.