Croton hirtus L’Hér.

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 : 15-16

10. Croton hirtus L’Hér.

Croton hirtus L’Hér. (1784) 17, t. 9; J. Sinclair (1956) 1, f. 1; G.L.Webster & D.G.Burch (1967) 262; Whitmore (1973) 84; Philcox (1997) 88; Esser (2005) 206. — Brachystachys hirta (L’Hér.) Klotzsch (1843a) 47. — Croton glandulosus L. var. hirtus (L’Hér.) Müll.Arg. (1866) 684; Airy Shaw (1981a) 284;Chakrab.& N.P.Balakr.(1997 ‘1992’) 48. — Oxydectes glandulosa (L.) Kuntze var. hirta (L’Hér.) Kuntze (1891) 614. — Croton glandulosus L. subsp. hirtus (L’Hér.) Croizat (1948) 401. — Type: Richard s.n. (holo P [P00623551]*; iso P [P00623550]*), French Guiana.

[For other synonyms see Plants of the World Online (http://www.plantsoft- heworldonline.org/) except for Podostachys hirta (L’Hér.) Klotzsch (see note).]

Erect, annual herbs, to 40 cm high; whole plant with hispid, irritating trichomes. Indumentum consisting of stellate-porrect, whitish to pale brownish trichomes, 0.6–1.5 mm diam on leaves, up to 3 mm diam on stems, flat but usually with distinctly longer central porrect radius, with 6–12 (on adaxial side often only 2–6) free radii. Stipules filiform, 4–7 by 0.2–0.5 mm, with scattered trichomes, quite persistent. Leaves alternate below, but crowded to pseudo-verticillate on apical branches; petiole 0.5–2(–4) cm long, flattened, slightly sulcate, hispid; glands as stalked discs lateral-abaxial on the petiole/blade junction, stalk 0.5–1.5 mm long, 0.2–0.4 mm diam; blade ovate, 1.9–5.4 by 1.1–4.1 cm, 1.1–2.1 times longer than wide, chartaceous, base rounded to obtuse, margin double serrate, apex acute, adaxial side with scattered trichomes to slightly hispid, abaxial side densely hispid; venation distinctly triplinerved, indistinct and sunken on adaxial side, distinct on abaxial side; secondary veins 3–5 pairs, not looped and closed near margin. Inflorescensces thyrsoid, 2–5 cm long, erect, basal 2–7(–12) nodes with a pistillate flower, never staminate flowers in the same cymule of a pistillate flower; bracts filiform, 1.5–4 by 0.1– 0.3 mm, scarcely hispid, with 1–3 pairs of filiform, gland-tipped, free or partly fused lobes at base. Staminate flowers c. 2 mm diam; pedicel c. 1 mm long, slightly flattened, hispid; sepals ovate, c. 1 by 0.5 mm, hyaline, outside pubescent, with a patch of simple trichomes on apex; petals oblong, c. 1 by 0.3 mm, hyaline, outside glabrous, inside slightly lanate; stamens 10 or 11, filaments 0.5–1 mm long, slightly fused at base, subglabrous, anthers c. 0.4 by 0.4 mm. Pistillate flowers c. 2 mm diam but soon to 5–7 mm diam; pedicel c. 0.3 mm long (up to 2 mm in fruit), hispid; sepals obovate, c. 1.5 by 0.5 mm, soon elongating to 3.5–4 by 1–1.5 mm (up to 7 by 2 mm in capsules), fused at the base, spreading at the apex, hispid outside, glabrous inside, longer than ovary; petals absent; ovary globose, c. 2 by 2 mm, hispid; stigmas c. 1.5 mm long, once divided to c. 1.4 mm from apex. Capsules subglobose, 3–4.5 by 2.5–4 mm, smooth, slightly sulcate, sparsely pubescent; pericarp very thin (c. 0.1 mm); columella 2.5–3 mm long. Seeds globose, slightly flattened, c. 3 by 2 mm, variously mottled, shiny but minutely reticulate-foveolate, carunculate.

Distribution — Native to C and S America; introduced and naturalizing in W and E Africa, Sri Lanka, Thailand, throughout Malesia including Sumatra (Sumatera Selatan).

Habitat & Ecology — Weed on waste places, old plantations, roadsides. Altitude: sea level to 100 m. Flowering and fruiting: February, March, June.

Affinities — Croton section Geiseleria subsection Geiseleria ( Riina et al. 2021) .

Note — Podostachys hirta (L’Hér.) Klotzsch (1841: 194) is mentioned by Plants of the World Online (http://www.plant- softheworldonline.org/) as a synonym, but Klotzsch indicates it as his own species (a nomen nudum) and there is no reference to L’Héritier de Brutelle, therefore, the name is not considered here to be a synonym.