Sapindus oocarpus Radlkofer (1910: 302)

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 : 33-34

7. Sapindus oocarpus Radlkofer (1910: 302) ( Figure 12 ).

Lectotype (first-step designated by Leenhouts 1994, second-step designated here):— VIETNAM. Hòa Bình: Tonkin, Forêts du Mount- Bavi , November 1887, G. J. B. Balansa 3430 (lectotype, P02297180 !; probable isolectotypes, M-0224794!, P02297179 !, P02297181 !, P06693215 !).

Etymology:—For the egg-like shape of the mature mericarps.

Description:—Tree, 5–12 m tall. Petiole 6–12 cm long, pale yellow to dark gray, glabrous, unwinged; rachis glabrous, unwinged; leaflets 6–12; petiolule 2–6 mm long, glabrous; leaflet blade broadly elliptic to ovate-lanceolate, symmetric or nearly so, straight to scarcely falcate, the apex not acuminate to abruptly acuminate with an obtuse tip, (6.5) 8–16 cm long, 3.7–6.5 cm wide, 2–2.2 times longer than wide, adaxially drying dark green, glabrous, the blade sunken along the midrib, secondary veins pale orange-yellow, tertiary and quaternary venation prominent and raised, discolorous to nearly concolorous with the blade surface, abaxially drying pale green, glabrous, secondary veins prominent, pale yellow, tertiary and quaternary venation prominulous, discolorous to nearly concolorous with the blade surface; foveolae conspicuous, exudates dull. Petals not observed. Mature mericarp 31–39 mm long, 20–26 mm wide, glabrous, pericarp 0.8–1.2 mm wide, seed 23–25 mm long, 16–18 mm wide, the rim 2.9–3.8 mm wide.

Distribution, habitat, and phenology:—Northern Vietnam (Hòa Bình and Nghệ An) ( Fig. 4 ), 0–1000(?) m. Forests. Flowering time unknown.

Notes:— Sapindus oocarpus is retained as a distinct species in sect. Sapindus , in accord with Radlkofer (1932a, 1932b). With doubt, Leenhouts (1994) placed S. oocarpus in the synonymy of a very broadly defined S. saponaria . The assignment of S. oocarpus to sect. Sapindus is tentative, as flowers have not yet been observed. Radlkofer (1910, 1932b) thought S. oocarpus was related to S. mukorossi (as “Affinis Sapindo Mukorossi ”). Sapindus oocarpus differs by its leaflets being broadly elliptic to ovate-lanceolate and 2–2.5 times longer than wide (vs. ovate-lanceolate to ovate-elliptic and 2.5–5 times longer than wide in S. mukorossi ), larger and ellipsoidal mature mericarps (31–39 mm long vs. 15–25 mm long and subglobose), larger seed (23–25 mm long, 16–18 mm wide vs. 12–15 mm long and wide), and thicker testa (2.9–3.8 mm wide vs. 1–2.5 mm wide).

Two specimens at P clearly state “Spontane!” and November 1887 on the label. The specimen labels for P02297179 and P06693215 are in a different handwriting, stating “ Hanoi, dans les jardins” and “1886”, but they are otherwise identified as the same collection (Balansa 3430). The specimen at M is a fragment merely labeled as Balansa 3430 .

Conservation Status:—The species is known from only two locations, each represented by one collection. Given the distance between the two locations, it could be inferred that the species has a large extent of occurrence. It is difficult to speculate how large the population may be. At this time, it seems best to consider the species Data Deficient ( IUCN 2012).

Specimens examined:— VIETNAM. Nghệ An: Annam, entre les villages de Kê Se et Lo Bui Phu Qui. pro: de

Vinh, “ 6-8-1929 ”, Poilane 16593 (P).

Figures

FIGURE 4. Native distribution of cited specimens of Sapindus in eastern Asia and western Oceania (cultivated or naturalized occurrences are not mapped). Sapindus saponaria subsp. jardinianus is abbreviated as “sap. subsp. jard.”. The symbol for the occurrence of S. saponaria subsp. jardinianus in Hawaii is placed beside Hawaii on the map. Two species endemic to Vietnam (S. chyrsotrichus and S. sonlaensis) are not here considered to be part of sect. Sapindus.

FIGURE 12. Sapindus oocarpus, clockwise from top-left: fertile branch, fruit pericarp and seed, leaflet adaxial surface, leaflet abaxial surface (photo by M. Lowry), and petiole base (Balansa 3430, courtesy of Muséum national d’Histoire naturelle [MNHN] – Paris Herbarium, Paris, France, Vascular plants collection [P]).