Croton hoffmannii Müller Argoviensis (1865: 86)

Caruzo, Maria Beatriz Rossi & Cordeiro, Inês, 2013, Taxonomic revision of Croton section Cleodora (Euphorbiaceae), Phytotaxa 121 (1), pp. 1-41 : 25

13. Croton hoffmannii Müller Argoviensis (1865: 86) . Croton hoffmannii var. incanus Müller Argoviensis

(1865: 86) ( Fig. 4F–K ). Type:— COSTA RICA. San José, s.dat., C. Hoffmann 547 (holotype B†, lectotype MO!,

here designated).

Croton hoffmannii var. viridis Müller Argoviensis (1865: 86) . Type:— COSTA RICA. s.dat., C. Hoffmann 548 (holotype B†, photo F!).

Croton longiradiatus Lanjouw (1931: 33) . Type :— SURINAME. s.dat., B.W. Brownsberg 6711 (holotype U!, isotypes L!, P!).

Shrubs to treelets 1.5–8 m tall; stellate and multiradiate trichomes, rarely appressed-stellate trichomes; branchlets cylindric, slightly striate, pubescent, brown and pale multiradiate trichomes. Leaves slightly discolorous, with a pair of sessile saucer-shaped acropetiolar glands; lamina 6–22 × 2–18 cm, ovate to cordate, rarely ovate-lanceolate, apex acute to acuminate, base cuneate to cordate, margin inconspicuously serrate to serrate, with glands; upper surface glabrescent, simple trichomes, stellate trichomes mainly on the midvein, lower surface pubescent to sparsely pubescent, stellate and multiradiate trichomes, rarely appressedstellate; venation pinnate, brochidodromous; petiole 0.4–8 cm long; stipules 2–6 mm long, entire, linear to linear-lanceolate. Inflorescences 11–52 cm long, terminal, rarely axilar, lax, pendant, usually apparently branched; inflorescence axis cylindric, slightly striate, pubescent, stellate trichomes; proximal cymules bisexual, with 1 pistillate flower and 1–2 staminate flower, distal cymules with 2-4 staminate flowers; bracts 0.2–1 cm long, entire, linear to lanceolate, deciduous; prophylls 1–4 mm long, linear. Staminate flowers 0.6–1 cm long, campanulate, pedicellate; pedicels 2–6 mm long; calyx ca. 4 mm long, pubescent externally, pale stellate trichomes, glabrate internally; calyx lobes 5, united up to half of their length, then free for the terminal ca. 2 mm, entire, equal, valvate, ovate a triangular, apex acute, margin villose; petals 3–5 mm long, spathulate, apex wavy and indented, pubescent externally, stellate trichomes, glabrate internally; disk 5-segmented; stamens 15–17, filaments subulate, villose at the base, simple trichomes, anthers arrow-headed; receptacle villose with simple trichomes. Pistillate flowers 0.8–1.2 cm long, campanulate, pedicellate; pedicels 2–5 mm long, usually thicked and angled at the apex; calyx 5–7 mm long, pubescent externally, pale stellate and multiradiate trichomes, brown trichomes mainly on central part of the calyx lobes and at the base of the calyx, near the receptacle, glabrate internally; calyx lobes 5, united up to half of their length, then free for the terminal 2.5–3.5 mm, entire, equal, imbricate, rhomboidal, sometimes with borders in a different texture, apex acute to shortly acuminate, margin villose; petals absent; disk entire, flatly 5-lobed; ovary subglobose, pubescent to hirsute, brown stellate and stellate-porrect trichomes; styes 3, 4-fid, united at the base, each one entire up to 1/3 of their length then branching into 12 terminal arms, covered by stellate trichomes, slightly exserted from calyx. Fruits 1.5–2.8 cm long, subglobose, 3-angled, smooth, pubescent, brown stellate trichomes; calyx lobes persistent, inconspicuously accrescent, pedicels conspicuously accrescent; seeds 5–7 mm long, rhomboidal a subglobose, ribbed.

Distribution and habitat: — Croton hoffmannii occurs in Costa Rica, Suriname (here known only by the type-collection of its synonymous, C. longiradiatus ), French Guiana and Brazil, in moist and dry forests, at 200–1300 m elevation.

Phenology:— Flowering in February, April–August, October and December; fruiting in March, August– October and December.

Taxonomic notes: —Among the other species of Croton section Cleodora , C. hoffmannii is most similar to C. rottlerifolius , which occurs in seasonally dry forests of Brazil and Bolivia. Besides the disjunct distribution between them, these two species can easily be distinguished by several vegetative and reproductive features (table 2).

Selected specimens examined: — COSTA RICA. Cartago: Cantón de Paraíso, along the driveway through the coffee plantation uphill from the Hotel Tapanti Media , approximately where the road leaves the coffee plantation and enters secondary vegetation, 9º47’19.6N, 83º50’30.6W, 1080 m, fl., 15 April 2006, B. van Ee & M. van Ee 598 (MICH, WIS) . FRENCH GUIANA. Guyane: Saül , tropical moist forest, 3º37’N, 53º12’W, 200- 400 m, fr., 26 March 1983, S. Mori 15388 (MO, NY, P) . BRAZIL. Roraima: arredores do marco divisor no. 10, mata de terra firme, 700 m, fr., 4 September 1979, N.A. Rosa & O.C. Nascimento 3275 (INPA, K, MG, NY) .

Figures

FIGURE 4. A–E. Croton heterocalyx. A. Flowering branch, detail of foliar stellate trichome (Caruzo et al. 108). B. Pistillate flower (Caruzo et al. 108). C. Styles arms detail (Caruzo et al. 108). D. Staminate flower (Caruzo et al. 108). E. Fruit (Caruzo et al. 108). F–K. Croton hoffmannii. F. Flowering branch (Luteyn 725). G. Pistillate flower (Luteyn 725). H. Gynoecium (Luteyn 725). I. Staminate flower (Luteyn 725). J. Stamen (Luteyn 725). K. Fruit (Mori 15388).