Sapindus mukorossi Gaertner (1788: 342

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 : 30-32

6. Sapindus mukorossi Gaertner (1788: 342 , tab. 70, figs. 3g and 3h) ( Figures 2 and 11 ).

Lectotype (designated here):—Gaertn., Fruct. Sem. Pl. 1: tab. 70, figs. 3g and 3h. Epitype (designated here):— JAPAN. C. P. Thunberg s.n. (epitype, UPS V-671953!) .

= Sapindus abruptus de Loureiro (1790: 238) .

Type:— China (not designated).

= Sapindus indicus Poiret (1805: 667) .

Lectotype (designated here):—Herb. Poiret (lectotype, P05186267!).

= Sapindus detergens Roxburgh (1832: 280) .

Lectotype (designated here):— INDIA. Bengal , April, W. Roxburgh s.n. (lectotype, G00096034 !; isolectotypes, B-W 07743 -01 0!, K000701948 !).

= Sapindus acuminatus Wall. ex Royle (1839: 137 , 139).

Lectotype (designated here):— NEPAL. N. W. Wallich 8035 (lectotype, K001128807 !, K001128808 !, K001128809 !).

= Sapindus utilis Trabut (1895: 199) .

Neoype (designated here): ALGERIA. 4 February 1896 [unclear if date of collection], Trabut s.n. ( MO2286296 ! & MO2286297 ! [2 sheet specimen]) .

= Sapindus mukorossi var. carinatus Radlkofer (1932b: 653–654) .

Lectotype (designated here): ALGERIA. Sétif: Hamma , 1895, collector not given ( P04766190 !).

= Sapindus boninensis Tuyama (1935: 449) .

Type :— JAPAN. Ogasawara Islands : Bonin, Ins. Hahazima, circ. Kitamura, 13 April 1934, T . Nakai & T . Tuyama s.n. (holotype, TI3125 !, isotypes, KAG036615 !, KAG036616 !, TI3124 !) .

Etymology:—The Japanese name for the species according to Thunberg (1784).

Description:—Tree, to 20 m tall, bark texture finely roughened, becoming exfoliated with irregular plates or scales. Petiole 4–10 cm long, glabrous to sparsely pubescent, unwinged (or narrowly winged on seedlings); rachis glabrous to sparsely pubescent, unwinged; leaflets (4)6–12(16); petiolule 1–10 mm long, glabrous to sparsely pubescent; leaflet blade ovate-lanceolate to ovate-elliptic, asymmetric to symmetric, falcate to nearly straight, the apex often acuminate with a bluntly acute to obtuse tip, 6–20.5 cm long, 1.5–8.5 cm wide, 2.5–5 times longer than wide, adaxially drying dark green to brown-green, glabrous or sparsely pubescent along the midrib, the midrib whitish green, at mid-blade the ridge 0.3–0.4 mm tall, 0.1 mm wide, the blade often sunken along the midrib edge, secondary venation pale yellowish to whitish green, tertiary and quaternary venation pale whitish green, discolorous from the blade surface, quinternary venation mostly obscure, abaxially drying pale green to green, glabrous to sparsely pubescent, the midrib pale yellow to reddish, secondary venation pale yellow, tertiary and quaternary venation pale green, slightly discolorous from the blade surface, quinternary venation mostly obscure; exudates reddish, conspicuous adaxially on midrib, petiole, and/ or rachis, and/or abaxially on leaf blade surface. Petal with 2 appendages, the appendage 0.5–1.5 mm long. Mature mericarp (15) 20–25 mm wide, pericarp 1–2.5 mm wide, seed 12–15 mm wide.

Distribution, habitat, and phenology:—Southeastern China ( Fig. 4 ), 10–500 m; cultivated and introduced elsewhere in Africa, Asia, Australia, Europe, and the USA (Florida). Flowering May–June in the northern hemisphere, December in the southern hemisphere.

Notes:— Sapindus mukorossi is distinguished by its winter-deciduous leaves, foliaceous cataphylls, usually unwinged leaf rachis, often distinct petiolule, relatively large leaflets with reddish exudates, appendaged petals, epigeal and phanerocotylar germination, and spring–summer flowering period ( Zhao et al. 2019). This species was accepted by Radlkofer (1932a, 1932b), but it has sometimes been considered a synonym of S. saponaria ( Leenhouts 1994, Xia & Gadek 2007). The two species differ in several respects (i.e. morphology, flowering period, and native distribution). Sapindus mukorossi is more similar to S. marginatus , sharing the same flowering period, appendaged petals, epigeal and phanerocotylar germination, the first true leaves being compound, and tolerance of freezing temperatures. There are several illustrations of the flowers and fruits of S. mukorossi ( Lecomte 1912, Chun 1921, Tuyama 1935, How & Ho 1955, Abdulla 1973, Ming 1977, Lo & Chen 1985).

Under the microscope, the reddish glandular exudates of S. mukorossi can usually be seen somewhere on the leaflet midrib or leaf rachis adaxially, or on the blade surface abaxially, but these can sometimes be inconspicuous or sometimes absent in immature plants. This species flowers in the late spring to early summer, even in the southern hemisphere (e.g. in Australia, Clemens 43169). Observations in Alachua County, Florida in 2022–2024 showed that adult trees had lost their leaves in January or February (after freezing or near-freezing temperatures had occurred) but some saplings low to the ground retained their leaves.

Gaertner described and illustrated only the fruits and seeds in the protologue of S. mukorossi , from material which has not been located (e.g. G, TUB). The protologue cited Thunberg (1784), and indented below that indicated that material from Houttuyn was examined (as “Ex dono Dn. Dr. Houtuyn”).As Houttuyn made no international collections himself, any fruits of Sapindus undoubtedly came from other collectors and quite possibly Houttuyn’s material had come from Thunberg ( Wijnands et al. 2017). The Thunberg specimen at UPS only consists of a stem and three leaves without fruit, and it cannot be assumed to be a duplicate of Houttuyn’s material. Houttyn’s (1774: 310–317) account of Sapindus probably predates his acquisition of Thunberg material from Japan ( Wijnands et al. 2017). Thus, the illustration from the protologue of S. mukorossi is chosen as lectotype, though it is demonstrably ambiguous and not diagnostic for species identification ( Sennikov 2022). The Thunberg specimen at UPS possesses the characteristic reddish exudates on the leaflet underside, and it is here designated the epitype.

The native region of S. mukorossi is presumably in southeastern China ( Radlkofer 1932b), with historic cultivation accounting for its widespread occurrence elsewhere in Asia ( Hiern 1875, Rehder & Wilson 1914, Diao et al. 2016, Bhatta et al. 2021). Sapindus mukorossi was cultivated in Algeria by 1845 ( Battandier & Trabut 1898, as S. utilis ). It was listed in cultivation in Indonesia ( Teijsmann & Binnendijk 1866), arrived to Florida in the late 1800s–early 1900s, and was later cited for Hawaii (St. John 1973). For a brief time in Algeria and Florida, there was economic interest in the soap-like properties and seed oil ( Moulie 1904, 1906a, 1906b, 1906c, Kidder 1905, Anonymous 1906, 1917, as S. utilis ). Recent studies have examined the potential of the seeds as a source of biodiesel ( Zhang et al. 2020). The plant has been used in medicine in Asia for a variety of applications ( Upadhyay & Singh 2012).

Following previous authors ( Merrill 1935, Ohwi 1965, How & Ho 1955), S. abruptus , described from Canton, China, is placed as a synonym, though no type material has been located (e.g. BM). A variety ( var. carinatus ) was recognized by Radlkofer (1932a, 1932b) from a few cultivated observations for the carinate fruits, but such a distinction does not appear tenable.

Several genomic analyses have been conducted on S. mukorossi ( Yang et al. 2016, Wang et al. 2021a, 2021b, Xue et al. 2022), and it has been included an ITS phylogeny with S. delavayi , S. emarginatus , and S. trifoliatus ( Mahar et al. 2017) . The chromosome count was recently recorded as 2 n =28 ( Xue et al. 2022), although another study reported n =18 (Verma et al. 2016).

Conservation Status:—The species should be classified as Least Concern ( IUCN 2012), as it is widespread ( Liu et al. 2022) and it is cultivated frequently.

Specimens examined:— 1877, Hort. Panormitanum ( M) ; Botan. Garten Palermo ( M) . AUSTRALIA. Queensland: Brisbane , December 1943, Clemens 43169 [cultivated] ( MICH) . CHINA. Fujian: Fukien, Changting , 26 May 1946, Tung 855 ( PE) . Guangdong: campus of Canton Christian College , 21 August 1925, Ping 1872 ( PNH) ; Li Chi Wei , 30 May 1928, Ying 432 ( MICH) ; Kochow , 21 August 1928, Ying 1028 ( MICH) ; Hoi Kong District , 5 June 1929, Ying 2586 ( MICH) . Guangxi: Luchen , 24 May 1928, Ching 5281 ( A) . Hainan: Kiung-shan District, Kiung-chow city and vicinity, July 1922, Fung 20267 [cultivated] ( BO) ; Paak Shek Shan , 17 June 1928, Tsang 745 ( MICH) ; Yeung Ling Shan , 25 June 1932, Lau 160 ( MICH) ; Kiung-chow , 18–30 July 1932, Fung 20267 [cultivated] ( MICH) ; Pak Shik Ling, Ku Tung Village , 30 October 1932, Lei 197 [cultivated] ( MICH) ; Yaichow, Mar-July 1933, How 70592 ( MICH) ; Hainan, 27 July 1933, Wang 33363 ( CINC) . Jiangsu: Ox Head Hill , 12 June 1922, Steward 2166 ( A) ; Ox Head Mountain, near Nanking , June 1922, Merrill 11389 ( PNH) ; Haichow Hills , 8 October 1922, Hers 2312 ( A) ; Ox Head Mountain , 24 August 1928, Keng 1918 ( MICH) ; Zijiang Shan , 22 June 1987, SAPSBET 45289 ( A) . Jiangxi: Kiangsi , Nanchang, Chung 630 ( AU) . Zheijang: Chekiang , 1927, Keng 865 ( PE) . FRANCE. Occitania: Montpellier , 43° 36’ 36” N, 3° 52’ 18” E, 17 m, 23 September 2019, Munzinger & Loup 8051 ( MPU) . HONG KONG. Tai Po: Ng Tung Chai , 1 August 1973, Chan 1145 ( MICH) ; Lam Tsuen, Taipo , 29 July 1998, Hu & But 23174 ( A) . INDIA. Chhattisgarh: Rai Pur, 2 June 1922 [flowers] & 28 December 1922 [fruit], Singh Katoch 27 (US). Himachal Pradesh: Kulu Valley, East Punjab , 23 May 1949, Sanha s.n. ( PNH) . Punjab: Kulu, Kangra , 29 December 1932, Koelz 3988 ( MICH) ; Bhadwar, Kangra , 9 May 1933, Koelz 4416 ( MICH) . Uttarakhand: Thadiar , May [flowers] & October [fruit], Rai s.n. (US); Dehradun , May 1929, Rozzet s.n. ( US). JAPAN. Kochi: Shikoku , Kajiya , Shimobun , Hidaka Village , Takaoka County, 33° 32’ N, 133° 23’ E, 20 m, 21 June 2003, Nomura FOK-609707 ( BRIT) . Miyagi: N Honshu, Shiroishi-shi, Oh-takazawa , 17 June 1975, Yashima s.n. ( BRIT) . Nagasaki: Inotsuki-men , 16 October 1996, Yonekura 96562 ( A) . Saga: Mt. Kurokami , Nishimatsura-gun, 1932, Makino s.n. ( BRIT) . NEPAL. Sudurpaschchim: Doti-Silgadhi , 7 April 1967, Ecker-Racz 44 (US) ; ibid., 31 May 1967, Ecker-Racz 84 (US). TAIWAN. Pingtung: Hengchun, Kenting Tropical Botanic Garden , 17 May 2003, Tunghai Univ. Biol. Collection Team 9205016 [cultitvated] ( PE) . USA. Alabama: Mobile County: Mobile , 27 November 1987, Burkhalter 10819 [cultivated] ( FLAS, FSU, UWFP) . Florida: Alachua County: Gainesville , 1 May 1936, Hume s.n. [cultivated] ( FLAS) ; University of Florida campus, 27 October 1968, D’Arcy s.n. [cultivated] ( FLAS) ; ibid., 8 October 1973, Meyer & Mazzeo 14390 [cultivated] ( FLAS) ; Kanapaha Botanical Gardens , 19 July 2006, Davis 1372 [cultivated] ( FLAS) ; University of Florida campus, 18 September 2008, Majure 3597 ( FLAS) ; ibid., 21 April 2011, Lange 950 [cultivated] ( FLAS) ; Dudley Farm Historic State Park , 28 May 2011, Riley 182 [cultivated] ( FLAS) ; University of Florida campus, 22 May 2022, Franck et al. 5677 ( FLAS) . Bay County: Mexico Beach , 29 August 1983, Montford s.n. [cultivated] ( FLAS) ]. Brevard County: west side of Grant Place, Melbourne, Shuey & Shuey 21 [cultivated] ( USF) . Calhoun County: Blountstown , 22 August 1949, Jackson s.n. [cultivated] ( FTG) ; ibid., 20 July 1978, Gholson, Jr. 7253 [cultivated] ( FLAS) ; ibid., 10 September 2011, MacClendon et al. 1131 [cultivated] ( USF) . Lee County: Introduced Estero , Buswell s.n. [leaf at top of sheet only] [cultivated] ( FTG) ; Estero , 5 April 1964, Craighead s.n. [cultivated] ( FTG) . Leon County: by Fla. Rt. 20, S side, W of Silver Lake Rd intersection ca. 1 mile, 1 June 1983, Godfrey 80676 [cultivated] ( FLAS) . Manatee County: Palmetto , 15 September 1953, McKay s.n. [cultivated] ( FLAS) . Marion County: W of McIntosh , 4 April 1990, Dressler s.n. [cultivated] ( FLAS) . Miami-Dade County: Sub-Tropical Experiment Station, Homestead , 31 August 1961, Craighead s.n. [cultivated] ( FLAS) . Orange County: Bithlo , 29 May 1929, Dodd s.n. [cultivated] ( FLAS) . Seminole County: edge of Oviedo , 17 July 1965, Beckner 723 ( FLAS) . Sumter County: Webster , 29 August 1949, Wadford s.n. [cultivated] ( FLAS) . Washington County: Chipley , 29 October 1999, Andreasen s.n. [cultivated] ( FLAS) . Georgia: Brooks County: near Quitman , 15 October 1975, Carr s.n. [cultivated] ( FLAS) . VIETNAM. Kon Tum: Distr. Dak Gley, 7 km to S of Dak Gley town, near Dak Pet village , 600–650 m, “ 12.11.1995 ”, VH 1513 ( BRIT, P) .

Figures

FIGURE 2. Morphology of various species of Sapindus. Top-left: seedlings of S. mukorossi (Franck 5932, FLAS), top-middle: seedling of S. saponaria subsp. saponaria (Wilder et al. 31737, SWF; photo by K. Relish), top-right: foliaceous cataphyll at base of newly emerging shoot of S. drummondii var. glabratus (Trelease 60, MO), bottom-left: exudates (e.g. white arrow) of glandular foveolae on abaxial leaflet surface of S. standleyi (Neill 2203, MO), and bottom-right: exudates (e.g. white arrow) of glandular foveolae on abaxial leaflet surface of S. mukorossi (Yonekura 96562, A).

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 11. Sapindus mukorossi, clockwise from top-left: fertile branch (Skean 1010, FLAS); petal adaxial surface with white arrow pointed at appendage (Franck 5677, FLAS), leaflet adaxial surface (SAPSBET 45289, A), leaflet abaxial surface (Ching 5281, A), and petiole base (Ching 5281, A).