Table 1 Comparison of morphological characters of Euphorbia normannii and other annual species from E. sect. Myrsiniteae and E. sect. Pithyusa

From: Evolutionary origin and systematic position of Euphorbia normannii (Euphorbiaceae), an intersectional hybrid and local endemic of the Stavropol Heights (Northern Caucasus, Russia)

Character E. normannii E. falcata E. aleppica E. gaillardotii
Cauline leaves Narrowly oblanceolate, entire, at base cuneate, with shortly acute or obtuse apex, 1.5–3 cm long and 2–4 mm wide, early deciduous Oblong-spatulate or narrowly oblanceolate, at base cuneate, shortly acute or obtuse at apex, entire or sometimes minutely dentate in upper part, 0.5–3.2 cm long and 3–7 mm wide, more or less persistent Numerous, narrowly linear, truncate at base, shortly acute at apex, entire, minutely papillose, 0.5–4.5 cm long and 0.2–1.5 mm wide Oblanceolate, reflexed, taped at base, acute at apex, minutely denticulate to subentire, 2–4 (5.5) cm long and 5–15 mm wide
Raylet leaves Oblong-elliptic to rhombic-elliptic, sometimes almost falciform, 0.5–1.6 cm long and 3–5 mm wide Triangular-elliptic and rhombic-elliptic to almost reniform, acute at apex, often aristate or acuminate, 0.5–1.8 cm long and 5–10 mm wide Ovate-rhombic or rhombic-elliptic, long acuminate, entire or irregularly crenate, 0.5–3 cm long and 6–18 mm wide Ovate-rhombic to suborbicular, 0.5–2.5 cm long and 5–20 mm wide
Cyathial glands Trapezoid or oblong-elliptic, 0.5–0.7 × 0.3–0.4 mm, with two tiny horn-like white appendages ca. 0.1 mm long Trapezoid or elliptic, 0.3–0.6 × 0.2–0.3 mm sometimes with horn-like appendages ca. 0.2 mm long, more often without them Elliptic or semilunate, 0.8–1.2 × 0.2–0.3 mm, with distinct horn-like appendages ca. 1 mm long Elliptic or trapezoid, 1.2–1.5 × 0.3–0.6 mm, without appendages
Capsule Slightly trilobate, 1.6–2.0 × 1.4–1.8 mm Minutely trilobate, 1.5–2 × 1.2–1.6 mm Distinctly trilobate, 1.5–2 × 2–2.5 mm Distinctly trilobate, ca. 1.8 × 2.2 mm
Seeds (Fig. 5) Oblong-ovoid, subtetrahedral, greyish, 1.3–1.5 mm long and 0.7–1 mm wide, irregularly longitudinally sulcate-foveolate; caruncule small, early caducous Oblong, compressed tetrahedral, 1.2–1.7 mm long and 0.7–1 mm wide, on facets with 5–10 regular transverse grooves; caruncule small, early caducous Ovoid-subglobose, subtetrahedral, minutely tuberculate, 1.3–1.5 mm long and 1–1.2 mm wide, ecarunculate Ovoid-ellipsoid, subtetrahedral, shallowly and irregularly pitted, 1.3–1.5 mm long, 0.8–0.9 mm wide