Euphorbia flavicoma

Caković, Danka, Cresti, Leonardo, Stešević, Danijela, Schönswetter, Peter & Frajman, Božo, 2021, High genetic and morphological diversification of the Euphorbia verrucosa alliance (Euphorbiaceae) in the Balkan and Iberian peninsulas, TAXON 70 (2), pp. 286-307 : 299

Identification key. — The most discriminating characters in the key are underlined. Images of all four species are shown in Figs. 9 and 10.

1. Stems 10–30(36) cm high, usually pubescent. Middle stem leaves usually slightly glaucous, (9)12–18(28) × 3–7(8) mm. Ray leaves (7)8–16(19) × (3)4–8(9) mm. Raylet leaves (4) 5–9(11) × (2)3–7(8) mm. Cyathial glands (0.3)0.5–0.8 (0.9) × (0.7) 0.9–1.5 mm, (0.7)0.8–1.2(1.3) times longer than wide. Capsule (1)2–4 × (1) 3–4.5 mm, with warts (0.1)0.2–0.7(1) × 0.2–0.4(0.5) mm, (0.4)0.5–2(3) times longer than wide. Seeds brownish ............. E. flavicoma

1. Stems (6)14–43(50) cm high, usually glabrous. Middle stem leaves green, (6)14–32(40) × (3) 6–13 mm. Ray leaves (7)11–22(32) × (4)7–15(18) mm. Raylet leaves (4)7– 14(20) × (3)5–10(13) mm. Cyathial glands (0.3)0.4– 0.9(1.2) × (0.6)0.9–2(2.5) mm, (0.3)0.4–0.7(0.8) times longer than wide. Capsule (1)1.5–4(4.5) × (1)1.5–4(4.5) mm, with warts 0.2–1.1(1.5) × 0.1–0.3(0.7) mm, (0.8)1–6(13) times longer than wide. Seeds usually greyish ............... 2

2. Leaves glabrous to densely hairy, with 0–32(63) hairs per mm 2 at the upper surface of the distal half of the leaf. Cyathial involucre (1)1.4–2.6(3.3) × (1)1.2–2(2.9) mm, (0.6)0.9–1.6(1.8) times longer than wide. Cyathial glands (0.3)0.4–0.7(1.0) × (0.6) 1.2–1.4 mm. Capsule (1.1)1.5– 3.0(3.7) × (1)1.7–3.5(4.2) mm. Warts on the capsule 0.2– 0.6(0.8) × 0.1–0.3(0.5) mm, (0.8)1.1–3.1(4.8) times longer than wide.......................................................... E. verrucosa

2. Leaves glabrous or rarely scarcely hairy, with 0–5(6) hairs per mm 2 at the upper surface of the distal half of the leaf. Cyathial involucre (1.5)1.9–3.9(5) × (1.3)1.4–2.6, 0.4–1(1.1) times longer than wide. Cyathial glands (0.4)0.5–1.0 (1.2) × (0.8)0.9–1.8(2.5) mm. Capsule (1.6)1.8–3.9(4.4) × 1.7–4.1(4.6) mm. Warts on the capsule 0.2–1.2(1.5) × 0.1– 0.3(0.7) mm, (1.2)1.5–6(13) times longer than wide.......... 3

3. Stem (16.8)18.8–43.0(48.3) cm high, (1.5) 2–3 mm thick. Middle stem leaves elliptic to elliptic-lanceolate (14) 14.5–30(38) × (7.3)7.5–12.7(13.2) mm, (1.3)1.5–3.1 times longer than wide. Leaf margin coarsely serrulate; the teeth 0.07–0.27(0.3) mm long and (0.11)0.13–0.36(0.46) mm wide at the base. Terminal rays (4.3)5.6–33(34.5) mm long, 0.3–1.7(1.8) times longer than ray leaves. Warts on the capsules 0.2–1.1(1.3) × (0.07)0.1–0.3(0.4) mm, (1.2)1.4–6.0 (13.0) times longer than wide .................. E. montenegrina

3. Stem 13.9–24.6 cm high, 1–2 mm thick. Middle stem leaves lanceolate 17.2–27.2 × 5–11.2 mm, 2.1–5.2 times longer than wide. Leaf margin sometimes minutely serrulate; the teeth up to 0.14 mm long and up to 0.18 mm wide at the base. Terminal rays 4.2–26 mm long, (0.3) 0.5–2.8(4.9) times longer than ray leaves. Warts on the capsules (0.6)0.7–1.4(1.5) × 0.1–0.3(0.7) mm, (2.2)2.6– 5.5(9.6) times longer than wide................... E. serpentini

Figures

Fig. 9. Habit and inflorescence details of: A, Euphorbia flavicoma; B, E. verrucosa. The upper right photo in B shows E. verrucosa (left) and E. montenegrina (right) grown together in the Botanical garden in Innsbruck. — Photos: B. Frajman.

Fig. 10. Habit and inflorescence details of: A, E. serpentini; B, E. montenegrina. — Photos: B. Frajman.