1. Drupe juicy, oval or spherical; stone ovoid or conical.............................................................2

- Drupe dry, swollen, spherical up to 1 cm in diameter, with a membranous swollen pubescent shell; narrow stone, almost fusiform, 0.8 × 0.2–0.3 cm. Thorny bush, prostrate, up to 20–40 cm high, with curved branches, pillow-shaped. Branches are grayish-white in color. Leaves narrow, linear-lanceolate, 20–40 × 1–3 mm. Inflorescence shoot short, up to 5–10 cm. Flowers white, small, up to 0.5 cm....................................................N. sphaerocarpa Maxim

2. Leaves obovate, oblanceolate or linear, entire above, very rarely 1–2-toothed; stipules membranous, deciduous....3

- Leaves spatulate or cuneiform, entire above or 3–5 crenate-toothed; stipules present........N. retusa (Forsk.) Aschers

3. Leaves entire, blunt at the apex, rarely pointed...................................................................4

- Leaves are the largest of all species of the genus, 25–46 × 6–9 mm, either entire or 1–2-toothed at the apex (on vegetative shoots); drupe large, round, juicy, pale pink to maroon in color, stone 10–12 mm long, 3.5–4.5 mm wide, ovoid pointed to apex, barely pointed or almost blunt; bush 1–1.5 m high................................N. roborowskii Kom.

4. Bush above 0.5 m, spreading-branching..........................................................................5

- Bush 0.1–0.3 m high, spreading, dense; leaves green, matte, oblanceolate with a pointed apex; number of flowers in the inflorescence 9–15; petals white, oblong-oval with short claws; drupe cherry, 7–8 × 4–5 mm, stone oblong-conical, 5–6 × 2–2.5 mm.............................................................................N. pamirica L.I. Vassiljeva

5. Drupe maroon to black in color, oval or spherical.................................................................7

- Drupe yellow, orange, pale to bright red, oval, confined to Central Asia............................................6

- Bush grows in Australia, leaves narrow at the apex, slightly pointed, stone conically ovoid.........N. billardierei DC.

6. Stems ascending, leaves greenish-yellow, narrow, long, linear spatulate, 25–28 mm long, 2–3.5 mm wide; petals yellowish-white, ovate with short claws; number of flowers per inflorescence 17–30; drupe oval, 8–12 × 7–11 mm; stone conically ovoid with a recurved apex, 8.5–11 mm long, 4.5–6 mm wide; drupe sap light pink.......................................................................................................N. komarovii Iljin & Lava ex Bobrov

7. Drupe black, oval or spherical; stone smaller than 7 mm..........................................................8

- Drupe oval, maroon to black in color, 7–10 × 6–9 mm; stone ovoid, obtuse, 7–10 mm long, 4.5–6.5 mm wide; bush 0.7–1.5 m high, spreading-branching; stems arcuate, with large spines; leaves dark green, shiny, oblong-spatulate, 20–26 mm long, 3–6 mm wide; flowers yellowish-white in color; petals ovoid or diamond-shaped with short claws; number of flowers per inflorescence 11–28; fruit sap pale reddish................................................N. schoberi L.

- Drupe oval, burgundy to dark purple in color, 8 × 6 mm; stone ovoid, obtuse, 6 × 3 mm; leaves oblong-lanceolate, 24–25 x 4.5–6 mm; bush 1–2 m high (up to 3–4)...................................................N. tangutorum Bobrov

8. Leaves pubescent or slightly pubescent...................................................9

- Leaves silvery from dense pubescence, calyx densely hairy, petals and ovaries hairy on the outside; leaf 10–15 × 4–6 mm..........................................................................N. praevisa Bobrov

9. Bush 0.6–1.8 m high, dense, with small spines; leaves oblanceolate, elongated, green, 14–16 × 2–3 mm; number of flowers per inflorescence 40–80 (90); petals white, ovate or rhombic with short claws; drupe black, oval or spherical, 4–6 × 4–4.5 mm; stone narrowly ovoid with a narrow pointed apex; 3.5–5 mm long, 2–2.5 mm wide; fruit sap green-black.....................................................................................N. iliensis Banaev&Tomoshevich

- Bush 0.2–0.8 m high, dense, with tightly arranged small spines and oblanceolate bluish-green leaves, 10–13 mm long, 2–3 mm wide; number of flowers per inflorescence 20–48; flowers white, pale-purple in buds; petals white, pointed-elliptical with narrow claws; drupe black, 4–9 × 4–8 mm; stone ovoid-acuminate, 3.6–6 mm long and 2.5–3.5 mm wide; fruit sap dark blue..............................................................................N. sibirica Pall.