Sapindus sonlaensis Tam et al. (2014: 131)

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 : 58-59

2. Sapindus sonlaensis Tam et al. (2014: 131) ( Figure 20 ).

Type:— VIETNAM. Sonla : Yen Chau District, Chieng Hac Commune, 700–1000 m, 2 February 1996, T. N . Ninh & V . Dumonter 59 ( VN 0059) (holotype: HN0000056011 !; isotype: HN0000056012 !) .

Etymology:—For the province of Sonla in Vietnam.

Description:—Tree, height and bark not observed. Petiole 2.5–4.2 cm long, sparsely puberulous, brownish to green, unwinged; rachis sparsely puberulous, unwinged; leaflets 6–10; petiolule 0–2 mm long; leaflet blade lanceolate to lanceolate-elliptic, symmetric to asymmetric, straight to slightly falcate, the apex acuminate with an obtuse to bluntly acute tip, 2.1–3.2 times longer than wide, adaxially drying brownish green, midrib brown-green, blade not or only slightly sunken along the midrib, secondary veins pale brownish green, the tertiary veins prominulous and nearly concolorous with the blade surface, the quaternary veins obscure, abaxially drying pale green to brownish green, the midrib pale yellow to brownish, secondary veins pale yellow, tertiary veins prominulous and nearly concolorous with the blade surface, the quaternary veins obscure. Petal with 2 appendages. Mature fruit not observed.

Distribution, habitat, and phenology:—Sonla Province, Vietnam ( Fig. 3 ); 700–1000 m. Secondary evergreen forest at the base of limestone mountains. Flowering in February.

Notes:—This species was described in detail in the protologue, and is known only from the type. It was thought to be dioecious since the type specimens only had staminate flowers (Tam et al. 2014). Like other species of Sapindus , S. sonlaensis could be duodichogamous ( Subba Reddi et al. 1983, Acevedo-Rodríguez et al. 2011), and the type specimen may have been collected during the male flowering phase. Although fruits were not observed, the Latin description indicated the ovary was pilose (Tam et al. 2014).

The type collection of S. sonlaensis was initially identified as Lepisanthes rubiginosa (Roxburgh 1796: 44) Leenhouts (1969: 82) , but this species differs by its strongly ferruginous-pubescent leaf rachis and young stems. The leaf rachis and young stems are only sparsely puberulous in S. sonlaensis . Tam et al. (2014) remarked that S. sonlaensis most closely resembled S. delavayi .

Conservation Status:—This species is known only from the type, and it is difficult to speculate the extent of its suitable habitat. Its total population cannot be reliably estimated. Therefore, the category of Data Deficient ( IUCN 2012) seems most appropriate at this time.

Figures

FIGURE 3. Native distribution of cited specimens of Sapindus in the Americas and eastern Oceania (cultivated or naturalized occurrences are not mapped). Longer names of some taxa are abbreviated, i.e. S. drummondii var. drummondii (abbreviated as drum. var. drum.), S. drummondii var. glabratus (drum. var. glabratus), S. saponaria subsp. jardinianus (sap. subsp. jard.), and S. saponaria subsp. saponaria (sap. subsp. sap.), The symbol for the occurrence of S. saponaria subsp. jardinianus in Hawaii is placed beside Hawaii on the map.

FIGURE 20. Sapindus sonlaensis, clockwise from top-left: fertile branch, flower and flower buds, leaflet adaxial surface, leaflet abaxial surface, and petiole base subtending an inflorescence peduncle (Ninh & Dumonter 59, HN). Photos by D.V. Hai.