Malesian Euphorbiaceae Descriptions
Stuppy, W., P.C. van Welzen, P. Klinratana & M.C.T. Posa. 1999. Revision of the genera Aleurites, Reutealis and Vernicia (Euphorbiaceae). Blumea 44: 7398.
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Reutealis Airy Shaw
Reutealis Airy Shaw, Kew Bull. 20 (1967) 394; G.L.Webster, Ann. Missouri Bot. Gard. 81 (1994) 114; Stuppy et al., Blumea 44 (1999) 85; Radcl.-Sm., Gen. Euphorbiacearum (2001) 331, Fig. 41; G.L.Webster in Kubitzki, Fam. Gen. Vasc. Pl. 11 (2014) 183 (sub Vernicia). Aleurites J.R.Forst. & G.Forst. section Reutealis Mόll.Arg. in DC., Prodr. 15, 2 (1866) 724. Type species: Aleurites trisperma Blanco [= Reutealis trisperma (Blanco) Airy Shaw]
Trees, monoecious, evergreen. Indumentum simple on developing shoots, stipules, leaves and petioles, stellate on lower surface of developed leaves, both simple and stellate on inflorescences, bracts, pedicels and buds, all parts glabrescent, greyish-white to light beige or rarely fulvous to ferruginous. Young twigs distinctly 5-ribbed, soon glabrescent. Stipules small, triangular, acuminate, the tip recurved, early caducous, leaving fairly prominent scars. Petiole terete, slightly ribbed or striate, usually displaying a conspicuous adaxial groove, with two sessile, discoid, concave (cup-shaped) glands at the apex exudating a sweet sap, black in dry leaves. Leaves alternate, simple, never lobed, ovate to broadly ovate; base truncate or shallowly to deeply cordate or reniform; margin entire; apex acuminate to cuspidate with a sessile, discoid gland at the top (c. 1 mm diam.); basally palmately 37-veined, pinnate along the midrib with 49 major lateral veins per side. Inflorescences terminal or rarely subterminal, solitary, many-flowered pyramidal thyrses, bisexual or rarely unisexual, with the flowers in bracteate clusters, protogynous with a solitary pistillate flower terminating each major axis, lateral cymules staminate; bracts oblong-triangular, acuminate, conspicuously hooded after anthesis. Flowers unisexual, actinomorphic, white; buds ovoid, apex acuminate; calyx bell-shaped, valvately rupturing for half to two thirds its length into 2 or 3, equal or unequal lobes, densely pubescent outside, glabrous inside; petals 5, free, imbricate, narrowly obovate-spathulate, rounded at the apex, drying dark brown to black, veins not distinct, clawed, glabrous on the inside except for the claw, latter with few simple, downwards pointing, white hairs, sericeous outside, the petals of the staminate flowers basally adnate to the staminal column; disc 5-lobed, lobes free, apically with a conspicuous tuft of upwardly directed hairs. Staminate flowers: pedicel short, stouter than in the pistillate flowers, densely puberulous; disc glands erect, alternipetalous, adnate to the staminal column, basally glabrous or subglabrous; stamens (7)8(10), in 2 whorls (5+25), united into a column, the 5 outer free for about half their length, slightly shorter than the 25 inner, the latter united for almost their entire length; filaments glabrous in their free parts, the staminal column sericeous; anthers basifixed, opening extrorsely with 2 longitudinal slits, glabrous; pistillode absent. Pistillate flowers: pedicel stout, densely puberulous; disc glands represented by minute triangular protuberances, much smaller than in the staminate flowers, tapering towards the apex; ovary superior, ovoid to subglobose, roughly tri- or tetragonous in cross section, slightly grooved along the septae, 3- or 4-locular, with 1 ovule per locule, sericeous; styles divergent, bi- or trifid, split up to more than half of their length, basally terete, the distal ends spathulately flattened, the lowermost part sericeous on the outside. Fruits large, capsular, subglobose, surface smooth, velutinous, with 3 or 4 distinct longitudinal ridges outside, apically rounded or narrowly attenuate towards and pointed at the apex, abruptly narrowed into the base, light brown when dry. Seeds ecarunculate, thick-discoid to subglobose, with suborbicular to broad-elliptic outline in dorsal view, dorsiventrally compressed, usually with a shallow, transmedian dorsal ridge, obtuse at both the micropylar and the chalazal end, medium brown to maroon with faint dark brown variegations, surface smooth; hilum large. Embryo straight, embedded in copious endosperm, cotyledons broad, flat.
Distribution Reutealis is a monotypic genus native to the Philippines (Luzon, Negros, Mindanao), also planted and naturalized in West Java.
Reutealis trisperma (Blanco) Airy Shaw, Kew Bull. 20 (1967) 395; Stuppy et al., Blumea 44 (1999) 86, Fig. 2. Aleurites trisperma Blanco, Fl. Filip. (1837) 755; Mόll.Arg. in DC., Prodr. 15, 2 (1866) 724; Hemsl., Bull. Misc. Inform. (1906) 121; Pax in Engl., Pflanzenr. IV.147 (1910) 131; J.J.Sm., Meded. Dept. Landb. Ned.-Indiλ 10 (1910) 556; Merr., Sp. Blancoan. (1918) 228; Enum. Philipp. Fl. Pl. 2 (1923) 448; Backer & Bakh.f., Fl. Java 1 (1963) 478. Camirium trispermum (Blanco) Kuntze, Rev. Gen. Pl. 2 (1891) 595. Neotype (designated by Stuppy et al., 1999): Merrill Species Blancoanae 145 (L, neo; iso in W, 2 specimens), Philippines, Luzon, Cavite Province, Maragondong.
Aleurites saponaria Blanco, Fl. Filip., ed. 2 (1845) 519; Fl. Filip., ed. 3, 3 (1879) 156, t. 296 (for synonymy see Fern.-Vill., Nov. App., 1880, 191). Lectotype (designated by Stuppy et al., 1999): Blanco, Fl. Filip, ed. 3, 3 (1879) t. 296.
Tree, up to 15 m tall. Bark pale grey to medium brown, lenticels few or absent. Stipules 46 by 23.5 mm. Petiole 4.525(32) by 15 mm; glands at the apex 0.51.5 by 12 mm. Leaf blade (4)816(28) by (2.5)715(22.5) cm, ratio 11.3. Inflorescences (4)820(30) by (4)821 cm; bracts 2.57 by 13.5 mm. Staminate flowers 610 by 1013 mm; pedicel 1.25 by 0.50.7 mm; buds 34 by 23 mm; calyx lobes 46 by 45 mm; petals 7.59.5(13) by 2.24 mm, claw 23 by 0.81 mm, basally along the middle shortly (0.51 mm) adnate to the staminal column; disc-glands triangular in dorsal view, strongly keeled on the back, 0.50.7 by 0.20.3 mm at the apex; outer filaments 2.73.5 mm long, inner filaments 3.55 mm long; anthers ellipitical, 0.81.1 by 0.40.6 mm. Pistillate flowers 78 by 810 m; pedicel 1.55 by 12 mm; buds 35 by 2.53.5 mm; calyx lobes 3.54 by 34 mm; petals 614 by 35 mm, claw 23 by 0.81 mm; disc glands c. 0.150.2 mm long and wide; ovary 2.54 by 23 mm; styles 1.82 mm long. Fruits 3.55.5 by 35 cm. Seeds 2232 by 2228 by 1720 mm.
Distribution As the genus.
Habitat & Ecology In forests at low and medium altitudes, but apparently nowhere abundant, occurring both in the forest and in and about towns as a cultivated tree.
Uses The oil yielded by the seeds was formerly employed in the Philippines for the production of a weak soap which was in demand among sailors owing to its property of lathering in sea water (Airy Shaw, 1967; Pax, 1910).
Vernacular names Philippines: Balukanag (Bisaya, Iloko, Tagalog); baguilumbang, balokanad, banukalad, banunkalag, calumban, kalumbang, lumbang-banukalad, lumbang-gubat (Tagalog) (Merrill, 1923).
Note The species was endemic to the Philippines before it was introduced to West Java where it is now cultivated in some areas (J.J. Smith, 1910).