Sapindus motu-koita A.R. Franck

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 : 28-30

5. Sapindus motu-koita A.R. Franck , sp. nov. (LSID: 77340322-1) ( Figures 1 and 10 ).

Type:— PAPUA NEW GUINEA. Central: Hill , Tana Highway, road to Brown R . Port Moresby subdistrict, 9° 30’ S, 147° 10’ E, 10 m, 7 August 1974, P . Katik s.n., LAE 62318 (holotype, LAE215500 !; isotypes, A01771341 !, BISH406609 !, BRI-AQ0320796!, CNS- QRS 19773.1 !, L2311311 !, L2311313 !, US 01056781!).

Diagnosis:— Sapindus motu-koita has small mericarps (9–12 mm wide) like S. balicus and S. tricarpus . The distinctive characters of S. motu-koita are the petiolules 0–1 mm long, leaflet blades 1.5–2.5 times longer than wide with prominulous to obscure reticulate venation, and the pericarp 0.4–0.6 mm thick (vs. petiolules 1–4 mm long, leaflet blades 2.5–3.5 times longer than wide with strongly prominent reticulate venation, and pericarp 0.1 mm thick in S. balicus ; and petiolules 0–1 mm long, leaflet blades 2.5–5.5 times longer than wide with prominulous to nearly obscure reticulate venation, and pericarp 0.1 mm thick in S. tricarpus ).

Etymology:—For the Motu-Koita people, the indigenous inhabitants of the Port Moresby region of Papua New Guinea ( Goddard 2020), where this species of Sapindus occurs.

Description:—Tree, to 15 m tall, bark smooth to rough, light to mottled gray with green fleck. Petiole 2–4 cm long, glabrous to sparsely puberulent; rachis glabrous, unwinged or wings to 5 mm wide on one side; leaflets 4–8; petiolule 0–1 mm long, pubescent; leaflet blade broadly ovate to ovate-lanceolate, generally symmetric, generally straight, the apex obtuse to shortly acuminate-obtuse, 4.5–12 cm long, 2.1–4.9 cm wide, 1.5–2.5 times longer than wide, adaxially drying pale green, glabrous, midrib pale green to pale yellow, at mid-blade the ridge 0.3 mm wide, 0.2 mm high, the blade even with the midrib or slightly ascending towards it, secondary veins pale green to pale yellow, tertiary and quaternary venation prominulous to obscure, intermediate in color between the secondary veins and blade surface to nearly concolorous with the blade surface, abaxially drying pale green, glabrous, midrib pale green to pale yellowish green, secondary veins pale green, prominulous, tertiary and quaternary venation prominulous to obscure, intermediate in color between the secondary veins and blade surface to nearly concolorous with the blade surface; exudates clear, inconspicuous abaxially on the blade surface. Petal without appendages. Mature mericarp 9–12 mm wide, pericarp 0.4–0.6 mm wide, seed 6–9 mm wide.

Distribution, habitat, and phenology:— Papua New Guinea ( Fig. 4 ), 0– 80 m. Eucalyptus forest, mangrove swamp, monsoon scrub. Flowering March–May.

Notes:—This species is distinguished by its leaflet blades 1.5–2.5 times longer than wide with relatively obscure venation nearly concolorous with the blade surface, mature mericarps 9–12 mm wide, pericarp 0.4–0.6 mm wide, and seeds 6–9 mm wide. It is endemic to Papua New Guinea. Previously specimens had been identified as S. saponaria ( Leenhouts 1994) . In addition to its distinctive morphology, the species is about 3,000 –4,000 km away from the nearest native populations of other species of Sapindus (i.e. S. balicus , S. tricarpus , and S. vitiensis ).

Conservation Status:—The species is known from a few subpopulations in a relatively small extent of occurrence (<5,000 km 2). Given the likelihood for continuing decline due to deforestation or forest degradation, the species ought to be deemed Endangered ( IUCN 2012).

Specimens examined:— PAPUA NEW GUINEA. Central : 1 mi. SE of Kapa Kapa, 50 ft., 14 August 1962, Schodde 2779 ( BO, US); Fairfax Harbour, 9° 55’ S, 147° 20’ E, sea level, 16 February 1965, Gillison NGF 22222 ( A, BISH, PNH, US); Rigo Road 13 mile, Moresby subdistrict, 25 June 1969, Streimann NGF 39489 ( A) ; near Mt. Lawes , Moresby subdistrict, 9° 10’ S, 147° 15’ E, 250 ft., 24 March 1971, Womersley NGF 43704 ( BISH, GH, PNH) .

Figures

FIGURE 1. Morphology of various species of Sapindus. A. Habit of S. thurstonii, from Rock (1913, Pl. 106). B. Mature fruit of S. motukoita (Schodde 2779, US). C. Mature fruit of S. saponaria subsp. jardinianus (Decker 2802, US). D. Immature fruit of S. trifoliatus (West s.n., FLAS). E. Immature fruit of S. rarak (Chow & Wan 80094, BISH). F. Adaxial side of petal of S. delavayi (Maire s.n., BISH). G. Adaxial side of petal with a sepal behind and an adjacent stamen of S. trifoliatus (Nageswara-Rao s.n., FLAS). H. Adaxial side of petal with the pistil along bottom of S. oahuensis (Degener 7356, US).

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 10.Sapindus motu-koita, clockwise from top-left:fertile branch (Schodde 2779, courtesy of the United States NationalHerbarium [US], Smithsonian Institution), petal adaxial surface (Womersley 43704, GH), leaflet adaxial surface and leaflet abaxial surface (Gillison NGF 22222, A), and petiole base (Schodde 2779, US).