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Euphorbia exstipulata - squareseed spurge

Scientific Family
Euphorbiaceae
Synonyms
Euphorbia exstipulata var. exstipulata, E. exstipulata var. lata
Other common names
Clark mountain spurge
Plant type
Forbs and Subshrubs
Origin
Native
Lifecycle
Annual
Similar species
Euphorbia aliceae, E. aliciae.
Height
6 to 8 inches
Riparian
No

Low annual herb, 6 to 8 inches tall; stems erect and branching, with branches spreading to ascending, often forked near the flower clusters at branch tips; plant minutely hairy.

Annual, branches often arch; stems often somewhat hairy, leaf blades stemmed, narrow, margins toothed; flower cluster gland appendages usually present, petal-like, white to pink, not covering the 4 to 5 yellow to pink glands.

Habitat

Found in dry rocky spots, desert scrub, grasslands, grassy plains with mesquite, oak and oak-juniper woodlands.

Plant Community
Desert Scrub
Grasslands
Pinyon Juniper Woodlands
Low elevation
4000
High elevation
6000

Flower Characteristics

Bracts form a cup with 4 yellow to pink glands around edge, each with white to pink petal-like appendages, sometimes divided into triangular lobes; ring of inconspicuous male flowers, each with single stamen; single, stalked female flower, lacks petals.

Flower color
Yellow, pink, whitish
Flower shape
Regular
Tubular
No
First bloom month
September
Last bloom month
September
Flower clusters
Rounded

Leaf and Stem Characteristics

Leaves narrow and opposite, 3/4 to 1-1/2 inches long, sharply serrated; most leaves clustered near branch tips and forking; short leaf stalks, with tiny gland appendages at the base of the leaf stems; midvein visible.

Leaf type
Simple
Leaf color
Green
Leaf shape
Narrow
Leaf margin
Toothed
Leaf attachment
Opposite
Leaves clasp
No
Leaf hairs
Leaves & stems
Spines
No

Fruit and Seed Characteristics

Capsules angled, distinctly 3-lobed, oblong, 1/8 inch wide, sparsely hairy.

Fruit type
Capsule
Fruit color
Green

Seeds white to gray or light brown, egg-shaped, wart-like bumps, bluntly 4-angled in cross-section, with 2 to 3 transverse ridges (right angles to length of the seed).