Sapindus sect. Sapindus

Franck, Alan R., 2024, Revision of Sapindus sect. Sapindus (Sapindeae, Sapindoideae, Sapindaceae), including the description of three new species, Phytotaxa 648 (1), pp. 1-71 : 13-14

Key to species of Sapindus sect. Sapindus

1. Mature mericarp ovoid to ellipsoidal, 31–39 mm long, 20–26 mm wide; Vietnam........................................................ S. oocarpus

- Mature mericarp subglobose to ellipsoidal, 10–25 mm long and 10–25 mm wide; Americas, Asia (incl. Vietnam), Melanesia, and Polynesia ........................................................................................................................................................................................... 2

2. Adaxial surface of petal with 2 densely pilose appendages 0.1–1.5 mm long arising near the petal blade base or claw apex, or appendage absent rarely in S. drummondii ; freeze-tolerant, winter deciduous, in the following spring new shoots with 2–3 oblong to obovate green, foliaceous cataphylls; flowering mid-spring–mid-summer ................................................................................. 3

- Adaxial surface of petal lacking a basal appendage, or only with tufts of hairs near the margin of the petal above the claw; freezeintolerant, evergreen or only briefly deciduous just before the new flush of leaves, shoots lacking foliaceous cataphylls (only non-foliaceous bud scales present); usually flowering late summer–early spring, or late-spring–mid-summer in S. standleyi , or year-round in S. saponaria in southern hemisphere and near equator ............................................................................................. 5

3. Petiolule and leaflet base along midrib abaxially densely villous to glabrous; leaflets 10–20, the blade 0.6–3 cm wide, 2.5–17 times longer than wide; mature mericarp 8–16 mm wide; seed 6–10 mm wide; germination hypogeal and cryptocotylar, first true leaves simple ......................................................................................................................................................................... S. drummondii

- Petiolule and leaflet base along midrib abaxially sparsely to moderately pubescent to glabrous; leaflets 6–14(16), the blade 1.5– 8.5 cm wide, 2.5–6 times longer than wide; mature mericarp 14–25 mm wide; seed 9–15 mm wide; germination epigeal and phanerocotylar, first true leaves compound ...................................................................................................................................... 4

4. Petiolule 0–3 mm long; leaflet blade lanceolate to ovate-lanceolate, 1.5–4 cm wide, 3–6 times longer than wide, adaxially the blade usually not sunken along the midrib, at mid-blade the midrib to 0.2 mm high, the midrib and secondary veins pale green, tertiary and quaternary veins nearly concolorous with the blade surface; exudates lacking or these clear adaxially along the rachis, leaflet midrib, and abaxially on the blade surface (also present ephemerally on developing leaves); mature mericarp 14–18 mm wide ..... ....................................................................................................................................................................................... S. marginatus

- Petiolule 1–10 mm long; leaflet blade ovate-lanceolate to ovate-elliptic, 1.5–8.5 cm wide, 2.5–5 times longer than wide, adaxially the blade often sunken along the midrib, at mid-blade the midrib to 0.4 mm high, the midrib and secondary veins whitish green to pale green, tertiary and quaternary veins conspicuous and discolorous from the blade surface; reddish, orangish, to yellowish exudates present adaxially along the rachis and leaflet midrib, usually abaxially on the leaflet blade surface especially near the base of the midrib (also present ephemerally on developing leaves); mature mericarp (15) 20–25 mm wide ...................... S. mukorossi

5. Larger dimension of mature mericarp 9–14 mm, the pericarp 0.1–0.6 mm thick; seed 6–9 mm wide ............................................ 6

- Larger dimension of mature mericarp (13) 15–20 mm, the pericarp 0.1–2 mm thick; seed 9–14 mm wide .................................... 8

6. Leaflet blades 1.5–2.5 times longer than wide; pericarp 0.4–0.6 mm thick ................................................................. S. motu-koita

- Leaflet blades 2.5–3.5 times longer than wide; pericarp 0.1 mm thick ............................................................................................ 7

7. Petiolule 1–4 mm long; leaflets 2.5–3.5 times longer than wide, adaxially with strongly prominent, raised tertiary, quaternary, and often some quinternary veins, strongly discolorous with the blade surface, abaxially the foveolae inconspicuous .......... S. balicus

- Petiolule 0–1 mm long; leaflets 2.5–5.5 times longer than wide, adaxially with obscure to prominent tertiary and quaternary venation, discolorous to nearly concolorous with the blade surface, the quinternary venation mostly unapparent or obscure and nearly concolorous with the blade surface, abaxially the foveolae usually conspicuous ................................................ S. tricarpus

8. Leaflets (4)6–8(10), the blade adaxially with strongly prominent, raised tertiary, quaternary, and some quinternary veins, strongly discolorous with the blade surface, the blade 3.1–5.5 times longer than wide, mostly falcate, the petiolules (0) 3–11 mm long; flowering January–February in the southern hemisphere ............................................................................................... S. marikuru

- Leaflets 4–12(14), the blade adaxially with obscure to prominent tertiary and quaternary venation, discolorous to nearly concolorous with the blade surface, the quinternary venation mostly unapparent or obscure and nearly concolorous with the blade surface, the blade 1.9–4(5) times longer than wide, straight to falcate, the petiolules 0–5 mm long or 1–10 mm long and leaflets 4–6; flowering January–December in the northern or southern hemisphere ............................................................................................................. 9

9. Leaflet adaxially usually drying or aging pale to moderately green to occasionally moderately brown, tertiary venation prominulous, lightly discolorous to nearly concolorous with the blade surface, quaternary venation prominulous to obscure, nearly concolorous with the blade surface, the blade not or scarcely sunken along the midrib; rachis unwinged or wings to 5 mm wide on one side .... ........................................................................................................................................................................................ S. saponaria

- Leaflet adaxially drying or aging dark green to dark brown, sometimes dark purplish or reddish brown, tertiary and quaternary venation prominent to prominulous, pale yellow to yellowish green, discolorous from the blade surface, quaternary venation prominent to prominulous, discolorous to nearly concolorous with the blade surface, the blade sunken or not sunken along the midrib; rachis unwinged or wings to 1 mm wide on one side (rarely the wings to 3.5 mm, in seedlings) .................................... 10

10. Petiole base generally greenish to pale yellow throughout (except grayish lignescent in older leaves); leaflet midrib brownish pale green, reddish brown, to dark brown, occasionally pale yellow towards the base; flowering May–July (or October) in the northern hemisphere ....................................................................................................................................................................... S. standleyi

- Petiole base speckled-brown or nearly uniformly purplish brown; leaflet midrib pale yellow to pale green; flowering August– October in the northern hemisphere, or flowering April–July in the southern hemisphere ........................................................... 11

11. Petiole base speckled-brown; leaves pubescent; leaflets 4–8, the petiolule 0–3 mm long, the blade 2.5–3.5 times longer than wide, adaxially the blade often sunken along the midirb; flowering August–October in the northern hemisphere ................ S. thurstonii

- Petiole base nearly uniformly purplish brown; leaves glabrous; leaflets 4–6, the petiolule 1–10 mm long, the blade 1.9–2.3 times longer than wide, adaxially the blade not sunken along the midrib; flowering April–July in the southern hemisphere .. S. vitiensis