Croton caudatus Geiseler

Beyer, J., Esser, H. - J., Eurlings, M. C. M. & Welzen, P. C. van, 2023, A revision of the genus Croton (Euphorbiaceae) in Sumatra (Indonesia), Blumea 68 (1), pp. 1-25 : 11-13

5. Croton caudatus Geiseler — Fig. 2b , 4

Croton caudatus Geiseler (1807) 73; Müll.Arg (1866) 599; Hook.f. (1887) 388; S. Moore (1925) 100; J.J.Sm. (1910) 352; Merr. (1921a) 336; (1923) 425; Gagnep.(1925) 286; Burkill (1935) 689 (‘ caudatum ’); Backer & Bakh.f. (1963) 477; Airy Shaw (1972a ‘ 1971 ’) 245; Whitmore (1973) 85; Airy Shaw (1975) 92; (1981a) 284; Chakrab. & N.P.Balakr. (1997 ‘1992’) 37, map 2; Philcox (1997) 94; Esser (2005) 198; P.T. Li & Esser (2008) 262; Chakrab. (2019) 3629. — Croton caudatus Geiseler var. genuinus Müll.Arg. (1866) 599, nom. inval. — Croton caudatus Geiseler var. caudatus : Kurz (1877) 375. — Oxydectes caudata (Geiseler) Kuntze (1891) 611. — Lectotype, designated by Chakrabarty & Balakrishnan 1997): Rottler s.n. (lecto C [C 10011161]!), India orientalis.

Croton racemosus Burm.f.(1768) 206 (‘306’), nom. rej. — Lectotype (designated by Esser 2001): Anonymous (Herb. Houttuyn) s.n. (lecto G!), Sri Lanka.

Croton aromaticus Gaertn. (1791) 119 (‘ aromaticum ’), nom. illeg., non L. (1753). — Type: Not indicated.

Croton denticulatus Blume (1826) 603 (’ denticulatum ’), nom. illeg., non Geiseler (1807); Miq. (1861) 180, 452. — Lectotype (designated here): Unknown s.n. (lecto L [L.2210974]!), (Java,) Nussa Kambang.

Crotondrupaceus Roxb.[(1814)69,nom.nud.(‘drupaceum ’)](1832)683(‘drupaceum ’). — Lectotype (designated by Chakrabarty 2019): Roxburgh s.n. ( BM [ BM000951447 ]*).

Croton malvifolius Griff. (1848) 200. — Lectotype (designated here): Griffith 2518 (lecto BM [ BM000951453 ]*), Boutan (= Bhutan). Other syntype: Griffith 1166 (GH [00099667]!), Bootan (= Bhutan).

Croton sumatranus Miq. (1859) 381. — Oxydectes sumatrana (Miq.) Kuntze (1891) 613. — Lectotype (designated here): Anonymous (likely Zollinger) s.n. (lecto U [U007934]!), Indonesia, Sumatra,Lampong (fragment).Another fragment, Zollinger 642 (A [00047516]!) was also indicated as duplicate, but Zollinger 642 is the type collection of C. caudatus var. oblongifolius (see next).

Croton caudatus Geiseler var. denticulatus Müll.Arg.(1866) 599. — Lectotype (designated here): Hooker & Thomson s.n., s.d. (holo GDC [ G00311925 ]*), Assam.

Croton caudatus Geiseler var. oblongifolius Müll.Arg.(1866) 600. — Lectotype (designated here): Zollinger 642 (lecto GDC [ G00311913 ]*; isolecto A [00047516]*,[00106972]!,GDC[ G00311912 ]!,[ G00311921 ]!,G [ G00434381 ]!, [ G00434382 ]!, L [ L 0234052 ]!), Indonesia, Java.

Croton caudatus Geiseler var. hispidus Hook.f.(1887) 389 (‘ hispida ’). — Type: not indicated.

Croton caudatus Geiseler var. ruminatus Hook.f. (1887) 389 (‘ ruminata ’). — Lectotype (designated here): Griffith s.n., 1845 (lecto K [ K000246831 ]*), India, Khasia Hills.

Croton caudatus Geiseler var. globosus Hook.f. (1887) 389 (‘ globosa ’). — Type: not indicated.

Croton caudatus Geiseler var. tomentosus Hook.f. (1887) 389 (‘ tomentosa ’). — Lectotype (designated here): Griffith s.n. (lecto K [ K000246826 ]*), India, Assam; other syntype: Wallich num. list no. 8938 (BM!, CAL [ CAL0000023625 ]*, K!, K-W!), India, Silhet.

Croton caudatus Geiseler var. malaccanus Hook.f. (1887) 389 (‘ malaccana ’); Ridl. (1924) 259. — Lectotype (designated here): Griffth KD 4775 (lecto CAL [ CAL0000023572 ]*; isolecto: K [ K000246829 ]* without number, [ K000246830 ]* without number, [ K000959168 ]* without number, [ K000959169 ]* without number, [ K000959170 ]*, M [M-0241964]!, GDC [ G00311922 ]!, GH [00099677]! without number, [00100129]! without number, W!, ZT!), Myanmar. Other syntype: Maingay KD 1376 (CAL [ CAL0000023573 ]*, GH [00047511]!, L [ L0233998 ]!, P!), Malaysia.

Croton caudatus Geiseler var. harmandii Gagnep.(1925) 286. — Lectotype (designated here): Couderc s.n. (P [ P00610256 ]*), Cambodia, Vat-Preah. Other syntypes: Harmand s.n. (A [00047489]!, K [ K000959152 ]*), Cochinchine, delta du Mè-Không; Pierre s.n. (P n.v.) Cochinchine, Prov. de Bien-hoa.

Croton caudatus Geiseler var. obovoideus N.P.Balakr. & Chakrab. (1985 ‘1983’) 190, f. 1. — Type: Sebastine 25343A (holo MH, n.v.; isotypes MH [ MH 00001136 *, MH 00001133 *, MH00001135 *, MH00001134 *), India, Kerala, Kottayam Dist., Velara .

Croton laccifer auct. non L.: Airy Shaw (1972a ‘ 1971 ’) 248.

Straggling shrubs, woody climbers or lianas, to 12(–25) m long; young branchlets densely pubescent, slowly glabrescent. Indumentum consisting of yellowish brown stellate-dendritic trichomes, with often a long central porrect radius, (0.1–) 0.3– 1.2 mm diam, with 6–13 free radii. Stipules filiform, 4–9 by 0.1–0.5 mm, sightly to densely pubescent on both sides, caducous. Leaves alternate; petiole 1–3.5(–5) cm long, round to slightly grooved above, densely to slightly pubescent; glands 1–2 (rarely 3–4) pairs of distinctly stalked discs, lateral on the very base of the abaxial midrib, 0.3–0.8(–1) mm diam, stalk 0.6–1(–2) mm long, additional smaller marginal glands common, 0.2–0.5 mm diam, stalk 0.1–0.6(–1) mm long ( Fig. 2b ); blade ovate to elliptic, 4–11 by 2.2–6.6 cm, 1.1–2.1(–2.5) times longer than wide, membranous to chartaceous, base cordate, sometimes nearly rounded, margin (double-)serrate to subentire, apex acute to acuminate, distinctly brownish pubescent on both sides (very variable in density), on veins more dense than in between, adaxial side less densely pubescent than abaxial side, leaf surface always visible; venation very distinct, sunken above, actinodromous with 3 or 5 prominent basal veins, secondary veins 4–7 pairs, higher order nerves reticulate. Inflorescences thyrsoid, 1–3 per node, 6 –18 cm long, bisexual (occasionally only staminate flowers), densely pubescent all over, basally 6–21 pistillate flowers, apically 1–2(–3) staminate flowers per node; bracts filiform, 2–3 by 0.1–0.2 mm, eglandular (very rarely with a small but distinct stalked gland), outside pubescent, inside subglabrous, soon caducous. Staminate flowers 4–5.5(–7) mm diam; pedicel 3–8 mm long, round, densely pubescent; sepals triangular-ovate, 2–3 by 1.2–2 mm, outside densely pubescent, lanate on margin and apex, inside glabrous; petals oblong to slightly obovate, 2.5–3 by 0.7–1(–1.5) mm, outside glabrous to slightly lanate, inside glabrous to slightly lanate; stamens 18– 30, filaments 2–4 long, anthers 0.5–1 by 0.3–0.5, free. Pistillate flowers 6– 8 mm diam; pedicel 1–2 mm long (up to 4 mm in fruit), densely pubescent; sepals triangular-ovate, 3–4 by 1.5–3.5 mm, outside slightly pubescent, inside (sub)glabrous, with a patch of simple trichomes on apex, sometimes margin with small glandular bumps, slightly longer than ovary; petals absent; ovary globose, c. 3 by 3 mm, densely yellowish hispid; style absent; stigmas 4–6 mm long, once divided to 3.9–5.9 mm from apex, slightly pubescent near base. Capsules globose, 12–20 mm high by 12–22(–25) mm diam, not sulcate, rough to slightly muriculate, densely brownish pubescent; pericarp woody, 0.5–1.3(–2) mm thick; columella 10–13 mm long. Seeds globose, partly flattened, 8 –10 by 8 –11 mm, with scattered trichomes to slightly pubescent, carunculate.

Distribution — Pakistan, India, Sri Lanka, Bangladesh, Nepal, Bhutan, China (Yunnan), Myanmar, Thailand, Laos, Vietnam, Cambodia, Malesia: Malay Peninsula, Sumatra (Aceh, Sumatera Utara, Sumatera Barat,Sumatera Selatan,Banka-Belitung), Java, Borneo, Philippines, Sulawesi, Lesser Sunda Islands; Australia.

Habitat & Ecology — In peat swamp forest, deciduous and evergreen forest, secondary forests and thickets, along rivers and streams.Altitude: sea level to 700 m. Flowering and fruiting the whole year through.

Affinities — The sole member of Croton section Caudati ( Van Ee et al. 2015) .

Uses — Mainly medicinal, a root decoction is used for purg- ing the intestines, also used when the person has a cold or is feverish, in combination with Plumbago the decoction can act as abortifacient. The leaves can also be used as poultice with fevers. Twigs are used in basketry (all Burkill 1935). In Indonesia, dried bark is used to relieve stomach disorders ( Esser 2005).

Notes — 1. Highly diverse in density of indumentum and size and amount of muricae on the capsules. Only one Sumatran collection with a pistillate flower, therefore material from the Malay Peninsula was also used. Only specimen Elbert s.n. (L.2211126) has a small gland on two floral bracts.

2. The type sheets of Croton caudatus var. obovoideus, Sebastine 25343 at MH, were later numbered B– D by Chakrabarty, but these are not part of the original collection numbers, all sheets are clearly duplicates of the same gathering.

Figures

Fig. 2 Different types of leaf glands. a. Croton heterocarpus, glands sessile and placed more adaxially on the apex of the petiole; b. C. caudatus, glands 1–3 pairs, distinctly stalked and abaxially on the midrib base; c. C. viridifolius, glands slightly stalked and located either on the leaf blade base or as in drawing on the side veins; d. C. macrocarpus: glands with a thick stalk located on the midrib base; e. C. adumbratus: glands sessile on the midrib base (a: LÖrzing 13830; b: Forbes 2989; c:Kleinhoonte 460; d:de Wilde & de Wilde­Duyfjes 20590; e:de Wilde & de Wilde­Duyfjes 19604; all L). — Illustration by Esmée Winkel,2021.

Fig. 4 Habit of Croton caudatus Geiseler. a. Habit; b. fruits; c. seed with lepidote hairs (a, b: source unknown; c: Maxwell 82­286, L). — Illustrations: a, b by Priyono, 1996; c by Esmée Winkel 2022.