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Home , Croton (plant), Euphorbioideae, Excoecaria, Hippomaneae, Neoshirakia, Sapium

A REVISION OF LOUR. ()

HANS-JOACHIM ESSER1

Abstract. A revision of the Asian Triadica is presented, with three species accepted, T. cochinchinensis, T. sebifera, and T. rotundifolia. For the latter species a new combination is proposed. One new synonym is included, as well as a key to and complete synonymy of all taxa, and a note on the validity of the name Croton macrocarpus. Keywords: Euphorbiaceae, , , , Triadica.

Triadica Lour. is a small genus of Euphorbi- important economic crop species in East aceae, subfamily , tribe Hippo- (“Chinese Tallow ”). The sarcotesta of the maneae, and is endemic to E. and SE. Asia. It was other species is thinner and less rich in palmitic described by Loureiro (1790). Because the flow- acid; these species are therefore economically ers are similar to those of several other genera of not important. the tribe, various authors united Triadica as a dis- Triadica was always accepted as either a genus tinct section with other genera of the or section. The opinions about limits and species Hippomaneae, such as Garden ex L. concepts however changed through time. (Baillon, 1858), L. (Müller, 1866), or Therefore the number of included species ranged Sapium Jacq. (Pax and Hoffmann, 1912). The from one (Hurusawa, 1954; Kruijt, 1996), two species are still often treated under Sapium, (Loureiro, 1790; Baillon, 1858; Govaerts et al., although Webster (1994) expressed serious 2000, but including several new synonyms) to six doubts about the identity of both. This history (Pax and Hoffmann, 1912; Tseng, 1997). The was reviewed in more detail by Esser (1999). present study follows largely the opinions of The genus is, however, well circumscribed Govaerts et al. (2000), with a third species added, and very probably monophyletic (Kruijt, 1996; for which a new combination is proposed. Some Esser et al., 1998). Therefore, it was accepted species are now considered as synonyms, but two as a distinct genus in recent years (Hurusawa, species included by former authors are accepted 1954; Esser, 1994, 1999, 2001; Kruijt, 1996; in separate genera (Esser, 1999; Govaerts et al., Govaerts et al., 2000). 2000): Stillingia japonica Siebold & Zucc. (now Important diagnostic (and very probably apo- in Esser), and Sapium baccatum morphic) characters are leaves with adaxial Roxb. (now in Esser). glands on the petiole apex and with the lower- Illustrations and distribution maps of all most lateral veins forming the basal margin of species are already available in previous publi- the blade, and fruits with an early caducous cations (cited under the relevant species below). pericarp, exposing with a whitish sar- TRIADICA cotesta. Additionally, the petioles are unusually long within Hippomaneae (Esser et al., 1998). Triadica Lour., Fl. Cochinch. ed. 1, 2: 598, 610. The variation patterns within Triadica are 1790. Stillingia sect. Triadica (Lour.) Baill., quite unusual. Whereas flowers and fruits show Étude Euphorb.: 511. 1858. Sapium sect. only minor morphological variation between Triadica (Lour.) Müll. Arg., Linnaea 32: 121. species, the species are separated largely by 1863. Excoecaria sect. Triadica (Lour.) Müll. characters of the leaves: shape, apex, and glands. Arg. in DC., Prodr. 15(2): 1210. 1866. TYPE: The whitish sarcotesta is unique in Triadica sinensis Lour. [= (L.) Euphorbiaceae. It yields oils and waxes in T. Small], lectotype designated by Webster (1994). sebifera (L.) Small, which are used for a wide Stillingfleetia Bojer, Hortus Maurit.: 284. range of purposes and make this species an 1837, nomen.

1 Arnold Arboretum of Harvard University, 22 Divinity Avenue, Cambridge, Massachusetts 02138, U.S.A. E-mail: [email protected] This work was funded by a Mercer Fellowship of the Arnold Arboretum, Harvard University. It was based on collections from the herbaria cited by Esser (1999), and additional collections of A, AAU, BK, BM, CMU, G-DC, GH, K, LINN, MICH, NSW, NY, and UC. I am grateful to Wendy Duan and Yuan Changchun for Chinese translations, and Anthony Brach for helpful comments.

Harvard Papers in Botany, Vol. 7, No. 1, 2002, pp. 17Ð21. © President and Fellows of Harvard College, 2002. 18 HARVARD PAPERS IN BOTANY Vol. 7, No. 1

Seborium Raf., Sylva Tellur.: 63. 1838. distinct pedicel 2Ð10 mm long; sepals 3, fused at TYPE: Seborium chinense Raf. [= base, sometimes divided and then appearingly Triadica sebifera (L.) Small]. more; disc and staminodes absent; ovary with 3 or , with white latex. carpels, smooth; style present; stigmas 3, undi- Monoecious. Glabrous. Stipules ovate-triangu- vided, eglandular. Staminate flowers with dis- lar, 0.5Ð2 mm long, eglandular. Leaves alternate; tinct pedicel 1Ð3 mm long; sepals 3, nearly petioles 1Ð7 cm long, glandular on the adaxial completely fused; 2 or 3, the filaments apex; blade simple, orbiculate, ovate or elliptic, short but distinct; disc or pistillode absent. margin entire, eglandular at base (the petiolar Fruits with a short but distinct pedicel; schizo- glands sometimes on the adaxial junction with carp nearly circular in outline, 3-seeded, slightly the blade), abaxially often with few submarginal to not sulcate, smooth, dry and woody, splitting glands, papillate-glaucous abaxially; lateral along the septa and soon after loculicidally; the veins eucamptodromous, the lowermost pair dif- septa remaining at the central columella to a ferent and forming the basalmost part of the large part, the remaining columella triquetrous, blade margin, veinlets reticulate. apically distinctly alate. Seeds often remaining terminal or in few terminal leaf axils, not com- attached to the central columella after dehis- pound, yellowish-green, elongate; floral bracts cence of the fruits, with a whitish or greyish sar- 1Ð2 mm long, with a distinct pair of spheroidal- cotesta, without caruncle or aril. cylindrical glands; pistillate flowers at base, one A genus of three species, distributed from per bract; staminate flowers numerous in apical to China, Celebes and the Philippines. part, (3Ð)5Ð8 per bract; bracteoles present, simi- Published illustrations are summarized in Esser lar to bracts. Pistillate flowers with a short but (2001).

KEY TO THE SPECIES OF TRIADICA 1a. Leaves orbicular [index 0.9Ð1.1(Ð1.3)], with the base cordate to rounded (very rarely obtuse) and the apex emarginate to mucronate; adaxial petiole apex with a single gland...... T. rotundifolia 1b. Leaves ovate to elliptic [index (0.8Ð)1.1Ð2.6], with the base cuneate to obtuse (very rarely rounded to cordate) and the apex acute to acuminate; adaxial petiole apex with a pair of glands ...... 2 2a. Leaves broad [index 0.8Ð1.4(Ð1.7)], apex distinctly acuminate; fruits 11Ð13 mm long; seeds 6Ð9 mm long, sarcotesta whitish, distinct ...... T. sebifera 2b. Leaves narrow (index 1.5Ð2.6), apex acute to subacuminate; fruits 7Ð9 mm long; seeds 3.5Ð5 mm long, sarcotesta greyish, thin ...... T. cochinchinensis

1. Lour., Fl. Cochinch.: Stillingia ? lanceolaria Miq., Fl. Ned. 610. 1790. Excoecaria loureiroana Müll. Arg. Ind., Erste Bijv.: 183, 461. 1861. in DC., Prodr. 15(2): 1217. 1866. Sapium Excoecaria ? lanceolaria (Miq.) cochinchinense (Lour.) Pax & K. Hoffm. in Müll.Arg. in DC., Prodr. 15(2): 1221. Engl., Pflanzenr. IV.147.v: 252. 1912, nom illeg. 1866. TYPE: INDONESIA. Sumatra: [non (Lour.) Kuntze, Revis. Gen. Pl. 3: 293. Padang, Paloe Pisang, without date, 1898, = Excoecaria cochinchinensis Lour.]. Teijsmann HB 549 (Holotype: U!; Shirakia cochinchinensis (Lour.) Hurus., J. Fac. Isotype: CAL). Sci. Univ. Tokyo, Sect. 3, Bot. 6: 318. 1954. Sapium eugeniaefolium Buch.-Ham. ex TYPE: VIETNAM. “Cochinchina”, without date, Hook.f., Fl. Brit. India 5: 470. 1888; Loureiro s.n. (Holotype: BM!; Isotype: BM!). Chakrab. & M. Gangop., J. Econ. Tax. Stillingia discolor Champ. ex Benth., Bot. 14: 184. 1990 (under Sapium dis- Hooker’s J. Bot. Kew Gard. Misc. 6: 1. color). TYPE: INDIA. Assam: Goalpara, 1854; Esser, Blumea 44: 198, 201. 1999, Wallich (leg. Buchanan-Hamilton) 7970 as syn. nov. Sapium discolor (Champ. ex (Holotype: K-WALL, microfiche!). Benth.) Müll.Arg., Linnaea 32: 121. Sapium laui Croiz., J. Arnold Arbor. 21: 1863. Excoecaria discolor (Champ. ex 505. 1940; Y. C. Tseng, Fl. Reip. Pop. Benth.) Müll.Arg. in DC., Prodr. 15(2): Sin. 44(3): 18Ð19. 1997 (under Sapium 1210. 1866. TYPE: CHINA. Hongkong: discolor). TYPE: CHINA. Hainan: Kan- without date, Champion s.n. (Lectotype, en District, Chim Fung near Fong Ngau designated by Esser, Blumea 44: 201. Po Village, 01Ð28 February 1935, S. K. 1999: K!; Isolectotypes, GH!, K!). Lau 5498 (Holotype: A!). 2002 ESSER, A REVISION OF TRIADICA LOUR. (EUPHORBIACEAE) 19

Tree up to 25 m tall. Deciduous. Leaves adaxial gland 1.5Ð2 × 1.5Ð2.1 mm, rarely withering red; petiole (1Ð)3Ð6 cm long, api- divided on single leaves; blade orbicular, 7Ð11 cally with a pair of adaxial glands, each of × 6Ð10 cm, index 0.9Ð1.1(Ð1.3), base rounded which 1Ð1.5 × 0.5Ð0.75 mm; blade narrowly to slightly cordate to slightly obtuse, apex elliptic to slightly ovate, (2.5Ð)6Ð12 × (1Ð)3Ð6 emarginate, rounded or mucronate, abaxially cm, index (1.5Ð)1.8Ð2.6, base cuneate to eglandular or with up to 6 glands per side, (rarely) obtuse, apex acute to acuminate, abax- 0.3Ð0.6 mm in diam., lateral veins in 9Ð14 ially with 0Ð3 laminar glands on each side, lat- pairs. c. 4Ð5 cm long, basally eral veins in 9Ð17 pairs. Inflorescences 4Ð12 with 1Ð8 pistillate flowers. Pistillate flowers: cm long, basally with 0Ð13 pistillate flowers. pedicel c. 1 mm long. Staminate flowers: pedi- Pistillate flowers: pedicel 2Ð4 mm long. cel 1.5Ð3 mm long; stamens not seen. Fruits: Staminate flowers: pedicel 2Ð3 mm long; sta- pedicel 2Ð3 mm long; schizocarp 11Ð12 × mens with filaments 0.75Ð1 mm long. Fruits: 14Ð15 mm, base not clavate; pericarp c. 1.5 mm pedicel 2.5Ð6 mm long; schizocarp 7Ð9 × 7Ð9 thick. Seeds c. 5 × 3 mm, sarcotesta greyish- mm, base often clavate, pericarp 0.3Ð0.4 mm pale but hardly white. thick. Seeds 3.5Ð5 × 3.5Ð4.5 mm, sarcotesta Illustrations were published by Tseng (1997: greyish-pale but hardly white. pl. 3 fig. 5Ð7). Illustrations were published by Ridley (Fl. Distribution and ecology: The distribution Malay Penins. 3: 316, pl. 155. 1924) and Esser of this species is more limited than that of the (1999: fig. 7). other taxa. It is endemic to few provinces of Distribution and ecology: This is the most China (Yunnan, Guangxi, Guizhou, Hunan, widespread species of the genus, distributed Guangdong; compare Lee 1956: map) and just from India through Thailand and Indochina to reaches Vietnam, and is characteristic for sub- China (up to Hubei and Zheijang), Borneo, tropical evergreen broadleaf forest, collected in Celebes and the Philippines (for maps see Lee, elevations up to c. 1,400 m. 1956: map; Esser, 1999: map 7). It grows in various types of disturbed forests and thickets, 3. Triadica sebifera (L.) Small, Florida Trees: also on dry places, often on acidic soils, in ele- 59. 1913. Croton sebifer L., Sp. Pl.: 1004. 1753 vations of up to c. 1,000 m. (as “sebiferus”). Stillingia sebifera (L.) Michx., Sapium hookeri Hook.f., mentioned as syn- Fl. Bor.-Amer. 2: 213. 1803. Sapium sebiferum onym by Govaerts et al. (2000), was only men- (L.) Roxb., Fl. Ind. Ed. 1832, 3: 693. 1832. tioned as nomen pro syn., and was therefore not Seborium chinense Raf., Sylva Tellur.: 63. validly published. 1838, nomen superfl. Excoecaria sebifera (L.) Müll.Arg. in DC., Prodr. 15(2): 1210. 1866. 2. Triadica rotundifolia (Hemsl.) Esser, comb. Carumbium sebiferum (L.) Kurz, Forest Fl. nov. Sapium ? rotundifolium Hemsl., J. Linn. Burma 2: 411, 412. 1877. Seborium sebiferum Soc. 26: 445. 1891. TYPE: CHINA. (L.) Hurus., Bot. Mag. (Tokyo) 61: 30. 1948. Guangdong: without locality, Aug. 1887, C. TYPE: CHINA. Canton: without date, Osbeck Ford 169 (Holotype: K!). s.n. (Lectotype, designated by Radcliffe-Smith, Baccaurea esquirolii H. Lev., Fl. Kouy- Fl. Pakistan 172: 86. 1986: LINN 1140.9 !). Tchéou: 159. 1914Ð15. TYPE: CHINA. Triadica sinensis Lour., Fl. Cochinch.: Guizhou: Lo-fou, 1908, Cavalerie 3458 610. 1790. TYPE: CHINA. “Circa can- (Lectotype, designated by Haegens, tonem sinarum”, without date, Loureiro Blumea Suppl. 12: 192. 2000: A!; s.n. (Holotype: BM?). Isolectotypes: E, K!, UC!). Sapium chihsinianum S. K. Lee, Acta Sapium rotundifolium var. obcordatum S. Phytotax. Sin. 5: 121, pl. 22. 1956; K. Lee, Acta Phytotax. Sin. 5: 121. 1956; Govaerts et al., World Checkl. Euphorb.: Y. C. Tseng, Acta Phytotax. 20: 106. 1562. 2000, as syn. nov. TYPE: CHINA. 1982 (under Sapium rotundifolium). Guangxi: Lingui (“Hsien Lin-kwei”), TYPE: CHINA. Guangxi: Mao’er Shan Yen, C. H. Chung 800257 Mountain (Mou-I-Shan), May 1948, L. (Holotype: IBG). H. Chun 900105 (Holotype: IBSC?). Sapium discolor var. wenhsienensis S. B. Tree to 10 m tall. Leaves: petiole Ho, Fl. Tsingliensis 1(3): 451, fig. 155. 2.5Ð4.5(Ð6) cm long, apically with a single 1981. Syn. nov. TYPE: CHINA. Gansu: 20 HARVARD PAPERS IN BOTANY Vol. 7, No. 1

Wenxian County, Pi Kou, Fan-Pa, Miao- Numerous illustrations were published, and kou, 01 Sep. 1959, C. Y. Chang 10447 particularly useful are those of Müller (in (Holotype: WUC). Mart., Fl. Bras 11.2: pl. 84. 1874), Pax and Sapium pleiocarpum Y. C. Tseng, Acta Hoffmann (1912: 238, pl. 44), Hurusawa Phytotax. Sin. 20: 105, fig. 1. 1982; (1954: fig. 45) and Lee (1956: pl. 22). Govaerts et al., World Checkl. Euphorb.: Distribution and ecology: The species is 1562. 2000, as syn. nov. TYPE: CHINA. widespread in Taiwan and the southern parts of Guizhou: Zheng’an, 06 November 1976, Japan and China (Yunnan and Hainan up to Y. Zhang 1 [Holotype: GBG (‘Herb. Gansu, Shandong and Henan; compare Lee, Guizhou Bot. Gard.’)]. 1956: map; Jin and Huang, 1984). It grows in a wide ranges of forest types, on different soils, Sapium sebiferum var. cordatum S. Y. under dry or moist conditions, is even tolerant Wang, Fl. Henan 2: 480. 1988; Govaerts to short-term flooding, in elevations up to c. et al., World Checkl. Euphorb.: 1563. 1,700 m. It is frost hardy. It is cultivated around 2000, as syn. nov. TYPE: CHINA. the earth, naturalizes easily where cultivated Henan: October 1978, S. Y. Wang s.n. and became a problematic, invasive weed in the (Holotype: HEAC). USA (Barrilleaux and Grace, 2000, and numer- Sapium sebiferum var. dabeshense B. C. ous other publications). Ding & T. B. Chao, Fl. Henan 2: 481. The species has a wide range of uses. The 1988; Govaerts et al., World Checkl. coat contains a solid fat (“Chinese Euphorb.: 1563. 2000, as syn. nov. Vegetable Tallow”), used for candles, soap etc. TYPE: CHINA. Henan: T. B. Zhao From the seeds a drying oil is extracted 78149 (Holotype: HEAC). (“”). The is also used as Sapium sebiferum var. multiracemosum source of a black dye, as timber tree, and as B. C. Ding & T. B. Chao, Fl. Henan 2: ornamental, among others. The history of culti- 480, fig. 1394. 1988; Govaerts et al., vation in China resulted in a considerable range World Checkl. Euphorb.: 1563. 2000, as of variation (Jin et al., 1997). syn. nov. TYPE: CHINA. Henan: Although the type collections of Sapium October 1978, S.Y. Wang s.n. (Holotype: chihsinianum and S. pleiocarpum could not be HEAC). studied, the synonymy proposed by Govaerts et Sapium sebiferum var. pendulum B. C. al. (2000) is most probably correct. Differences Ding & T. B. Chao, Fl. Henan 2: 481. in inflorescence length and the number of pis- 1988; Govaerts et al., World Checkl. tillate flowers and fruits (on which S. pleio- Euphorb.: 1563. 2000, as syn. nov. carpum was based) occur in most genera and TYPE: CHINA. Henan, T. B. Zhao species of Hippomaneae and do not distinguish 777104 (? 77104) (Holotype: HEAC). species by themselves. It is known that species of Hippomaneae usually flower with purely Trees to 13 m tall. Deciduous. Leaves: peti- staminate thyrses first, and in additional later ole 2Ð7 cm long, apically with a pair of adaxial flowering periods with bisexual or even pistil- glands, each 0.7Ð1 × 0.5Ð1 mm; blade broadly late thyrses, often of quite different size (Kruijt, elliptic to slightly ovate or obovate, 3.5Ð10 × 1996; various label data). 3Ð9.5 cm, index 0.8Ð1.4(Ð1.7), base obtuse From S. chihsinianum a paratype (Lau 28609, (very rarely rounded or even cordate), apex A) was studied. The species differs from the very distinctly acuminate, abaxially eglandular majority of collections of T. sebifera in a or with up to 5 glands per side, these 0.3Ð0.7 shorter leaf apex and a thin seed coat. The seeds mm in diam., lateral veins in 7Ð11 pairs. could not be compared, but a very similar, com- Inflorescences 4Ð16 cm long, basally with parably short leaf apex is also found on 0Ð17 pistillate flowers. Pistillate flowers: pedi- the Linnean type of T. sebifera. The paired cel 2Ð3 mm long; stylar column c. 2 mm long, basal leaf glands distinguish it clearly from stigmas 3Ð5 mm long. Staminate flowers: pedi- T. rotundifolia. cel 2Ð3 mm long; stamens with filaments Sapium discolor var. wenhsienensis,how- 0.4Ð0.7 mm long, anthers c. 0.4 mm long. ever, clearly belongs here too (and not to T. Fruits: pedicel 4Ð13 mm long; schizocarp cochinchinensis, as proposed by Govaerts et al., 11Ð13 × 13 mm, pericarp 0.8Ð1 mm thick. 2000); the leaf characters agree well, and the Seeds 6-9 × 4Ð7 mm, sarcotesta distinct, latter species has not been recorded for this whitish. province yet. 2002 ESSER, A REVISION OF TRIADICA LOUR. (EUPHORBIACEAE) 21

Croton macrocarpus Rchb. ex Müll.Arg., Ridl., Fl. Malay Penins. 5: 332. 1925, for a mentioned as synonym by Govaerts et al. Malesian species, is valid and legitimate, and (2000), was only cited as nomen pro syn., and the replacement name Croton grandifructus was therefore not validly published. This also Radcl.-Sm. & Govaerts, Kew Bull. 52: 187. means that the name Croton macrocarpus 1997, is superfluous.

NOMEN EXCLUDENDUM Triadica japonica (Siebold & Zucc.) Nakai = 1858, was not validly published, because the Neoshirakia japonica (Siebold & Zucc.) Esser author accepted Triadica not as a genus but (the combination under Triadica by Baillon, only as a section of Stillingia).

LITERATURE CITED

BAILLON, H. 1858. Ètude Générale du Groupe des JIN, D. J. AND H. K. HUANG. 1984. The distribution of Euphorbiacées. Masson, Paris. Sapium sebiferum Roxb. in relation to the environ- BARRILLEAUX, T. C. AND J. B. GRACE. 2000. Growth mental conditions. Guihaia 4: 71Ð80 (in Chinese). and invasive potential of Sapium sebiferum ———,H. HUANG, R. TANG, Q. TONG, D. SHI, AND (Euphorbiaceae) within the coastal prairie region: Z. HOU. 1997. The investigation on the variety The effects of soil and moisture regime. Amer. J. resources of Sapium sebiferum in China. Guihaia Bot. 87: 1099Ð1106. 17: 345Ð362 (in Chinese). ESSER, H.-J. 1994. Systematische Studien an KRUIJT, R. C. 1996. A taxonomic monograph of den Hippomaneae Adr. Jussieu ex Bartling Sapium Jacq., Anomostachys (Baill.) Hurus., (Euphorbiaceae), insbesondere den Mabeinae Pax Duvigneaudia J. Léonard and & K.Hoffm. Doctoral dissertation, University of Hochst. (Euphorbiaceae tribe Hippomaneae). Hamburg. Biblioth. Bot. 146. Schweizerbart, Stuttgart. ———. 1999. A partial revision of the Hippomaneae LOUREIRO, J. 1790. Flora Cochinchinensis. Ed. 1. (Euphorbiaceae) in Malesia. Blumea 44: 149Ð215. Lisbon. ———. 2001. Hippomaneae. Pages 352Ð394 in A. LEE, S. K. 1956. Genus Sapium in the Chinese flora. RADCLIFFE-SMITH, Genera Euphorbiacearum. Acta Phytotax. Sin. 5: 111Ð130, pl. 22, 23. Royal Botanic Gardens, Kew. MÜLLER, J. 1866. Euphorbiaceae excl. . E ANDOLLE ———, P. C. VA N WELZEN, AND T. DJARWANINGSIH. Pages 190Ð1286 in A. D C , Prodromus 1998. A phylogenetic classification of the Systematis Naturalis Regni Vegetabilis. Fleischer, Malesian Hippomaneae (Euphorbiaceae). Syst. München/ Masson, Paris. Bot. 22: 617Ð628. PAX,F. AND K. HOFFMANN. 1912. Euphorbiaceae- Hippomaneae. In A. ENGLER, ED. Das Pflanzenreich GOVAERTS, R., D. G. FRODIN, AND A. RADCLIFFE- IV.147.v (Heft 52). Engelmann, Leipzig. SMITH. 2000. World Checklist and Bibliography of TSENG, Y. C. 1997. Euphorbiaceae-Euphorbioideae- Euphorbiaceae (with Pandaceae). Royal Botanic Trib. Hippomaneae Reichb. Pages 2Ð23 in J. S. Gardens, Kew. MA, ED. Flora Reipublicae Popularis Sinicae HURUSAWA. I. 1954. Eine nochmalige Durchsicht des 44(3). Science Press, Beijing. herkömmlichen Systems der Euphorbiaceen im WEBSTER, G. L. 1994. Synopsis of the genera and weiteren Sinne. J. Fac. Sci. Univ. Tokyo, Sect. 3, suprageneric taxa of the Euphorbiaceae. Ann. Bot. 6: 209Ð342. Missouri Bot. Gard. 81: 33Ð144. blank page