| 1 | Midrib flat or prominent on the upper surface |
| 1' | Midrib impressed in the upper surface. |
| 2 | Twigs glabrous. |
| 2' | Twigs hairy. |
| 3 | Underside of leaves hairy. |
| 3' | Underside of leaves glabrous. |
| 4 | Leaves distichous. Seeds straight |
| 4' | Leaves spirally arranged. |
| 5 | Leaves 4-6 cm. Nerves 6-9 pairs. Petiole 3-4 mm |
| 5' | Leaves 7-45 cm. Nerves 5-17 pairs. Petiole 10-50 mm. |
| 6 | Leaves 15-45 cm. Nerves 12-17 pairs. Inflorescence a spike |
| 6' | Leaves 7-40 cm. Nerves 5-16 pairs. Inflorescence a panicle |
| 7 | Leaves distichous |
| 7' | Leaves spirally arranged. |
| 8 | Bracts persistent. |
| 8' | Bracts caducous. |
| 9 | Leaves shorter than 5 cm |
| 9' | Leaves longer than 5 cm. |
| 10 | Inflorescence not a spike. Inflorescence a fascicle |
| 10' | Inflorescence not a spike. Inflorescence a raceme or panicle |
| 10'' | Inflorescence a (basally branched) spike or a cone. |
| 11 | Petiole 3-10 mm. Leaves 6-22 mm. Nerves 6-13 pairs |
| 11' | Petiole 10-25 mm. |
| 12 | Petiole 10-15 mm. Leaves 4½-21 cm. Nerves 6-9 pairs. |
| 12' | Petiole 15-25 mm. Leaves 17-30 cm. Nerves 11-13 pairs |
| 13 | Inflorescence a (basally branched) spike or a cone in bud. |
| 13' | Inflorescence not a spike (rarely a cone in bud). |
| 14 | Petiole 3-4 mm |
| 14' | Petiole more than 5 mm. (When dubious under "15", look under 53. S. tricoccata.) |
| 15 | Leaves longer than 15 cm. Nerves more than 10 pairs. Twigs thick. Terminal buds hairy. Petiole more than 20 mm. Fruits 25-40 mm |
| 15' | Leaves shorter than c. 10 cm. Nerves less than 10 pairs. Twigs not thick. Terminal buds glabrous. Petiole 5-10 mm |
| 16 | Inflorescence a short spike, fascicle or panicle. |
| 16' | Inflorescence a (basally branched) raceme. |
| 17 | Fruits 1-celled. Inflorescence a panicle. Stone with ridges or grooves. Seed 1, not straight. |
| 17' | Fruits 3-celled. Inflorescence a fascicle. Stone smooth. Seeds more than 1, straight. |
| 18 | Leaves 1½-5 cm. Nerves 6-9 pairs. Fruits ellipsoid, 10-15 mm long. |
| 18' | Leaves longer than 5 cm. |
| 19 | Apex of leaf rounded to faintly acuminate. |
| 19' | Apex of leaf rather abruptly acuminate. |
| 20 | Leaves 5-8 cm. Nerves 6-9 pairs. Petiole 3-4 mm. Fruit unknown. |
| 20' | Leaves 6-18 cm. Nerves 6-13 pairs. Petiole 3-10 mm. Fruit ovoid to ellipsoid, 5-12 mm. |
| 21 | Fruit globose, 3-celled, the sterile cells filled with air |
| 21' | Fruit ovoid to ellipsoid, 1-celled |
| 22 | Leaves distichous. Leaves 14-36 cm long |
| 22' | Leaves distichous. Leaves at most 12 cm long. |
| 22'' | Leaves spirally arranged or pseudo-verticillate. Leaves pseudo-verticillate or at least 3-5 close together at the end of the flushes. |
| 22''' | Leaves spirally arranged or pseudo-verticillate. Leaves spirally arranged |
| 23 | Underside of leaves glabrous |
| 23' | Underside of leaves Hairy. |
| 24 | Leaf base 90-130°. Flowers solitary. Petiole 1-3 mm. Leaves ovate 2½-7 cm. Nerves 3-6 pairs. Fruit narrowly flask-shaped, c. 13 mm long |
| 24' | These characters not combined. Fruits ellipsoid to ovoid. |
| 25 | Petiole 3-4 mm. Leaves 4-12 cm. Nerves 7-11 pairs. Base of leaves 40-90°. Inflorescence more flowered. Bracts caducous. |
| 25' | Petiole ½-3 mm, if up to 4 mm, inflorescence 1-flowered. Nerves 4-9 pairs. |
| 26 | Leaves 4-9 cm, acumen 9-16 mm, base 40-90° |
| 26' | Leaves 9-12 cm, acumen 7-12 mm, base c. 90° |
| 27 | Acumen 1-3 mm. Inflorescence 1-flowered. Leaves 2-3½ cm. Bracts persistent. |
| 27' | These characters not combined. |
| 28 | Angle of leaf base 50-90°. Flowers solitary or in a few-flowered raceme. Bracts persistent. Petiole 1-2 mm. Leaves 2½-5½ cm. Nerves 5-9 pairs. Acumen c. 5 mm. |
| 28' | These characters not combined |
| 29 | Leaves crowded towards the end of the twigs. Twigs thick, with large leaf-scars. |
| 29' | Leaves evenly distributed. |
| 30 | Underside of leaves glabrous. (If leaf margin and petiole beset with closely spaced vesicular glands: 3. S. adenophylla.) |
| 30' | Underside of leaves hairy. |
| 31 | Inflorescence a spike. |
| 31' | Inflorescence a panicle |
| 32 | Leaves 4-6 cm. Petiole 3-4 mm |
| 32' | Leaves 6-25 cm. Petiole more than 5 mm. Nerves more than 10 pairs. Fruits ampulliform. Stone ampulliform |
| 33 | Upper side of leaves hairy (pulverulent) |
| 33' | Upper side of leaves glabrous. |
| 34 | Seeds not straight. |
| 34' | Seeds straight. |
| 35 | Petiole 3-4 mm |
| 35' | Petiole more than 5 mm. |
| 36 | Fruits ampulliform. Bracts persistent. |
| 36' | Fruits not ampulliform. |
| 37 | Inflorescence a panicle |
| 37' | Inflorescence a (basally branched) spike (a cone in bud) |
| 38 | Fruits to c. 10 mm long. |
| 38' | Fruits more than 10 mm long. |
| 39 | Leaf index more than 3. Leaf margin (and petiole) beset with closely spaced glands. Stone ellipsoid |
| 39' | Leaf index 2-3. Leaf margin (and petiole) often glandular but glands not closely spaced. Stone ampulliform |
| 40 | Angle of leaf base more than 60°. |
| 40' | Angle of leaf base less than 60°. |
| 41 | Angle of leaf base less than 90°. Twigs and underside of leaves (appressedly) pubescent, puberulous or pilose. Fruits not ampulliform, 2-3-celled. Stone with ridges or grooves. |
| 41' | Angle of leaf base more than 90°. Twigs and underside of leaves not appressedly pubescent or puberulous. Fruits ampulliform, 1-celled. Stone smooth |
| 42 | Petiole 1-10 mm. Fruits 13-18 mm long |
| 42' | Petiole 15-25 mm. Fruits 22-40 mm long |
