Croton organensis Baillon (1864: 324)

Caruzo, Maria Beatriz Rossi & Cordeiro, Inês, 2013, Taxonomic revision of Croton section Cleodora (Euphorbiaceae), Phytotaxa 121 (1), pp. 1-41 : 12-14

5. Croton organensis Baillon (1864: 324) ( Fig. 5A–C ). Type:— BRAZIL. Rio de Janeiro: Serra dos Orgãos ,

May 1839, J.B.A. Guillemin cat. 938 (holotype P[00634527]!).

Croton platycladus Müller Argoviensis (1865: 123) . Type :— BRAZIL. Bahia: 1832, J. Lhotsky s.n. (lectotype G-DC!, here designated); Bahia: s.dat., A.M.A.C. Limminghe s.n. (syntype G-DC!).

Croton oxyphyllus Müller Argoviensis (1873: 100) . Type:— BRAZIL. Rio de Janeiro: “in silvis primaevis prope Bananal, 800–1000 ped. supra maré”, s.dat., C.F.P. von Martius 318 (holotype M!).

Trees 4–15 m tall; latex clear; simple, stellate and dendritic trichomes; branchlets strongly flattened, striate, floccose, covered by dendritic trichomes. Leaves discolorous, with a pair of sessile basilaminar glands, inconspicuous and maculate, greenish, covered by stellate trichomes; lamina 7–26(30) × 2.5–10 cm, ovatelanceolate to elliptical, apex acuminate to long acuminate, rarely acute, base subcordate, obtuse to cuneate, margin irregularly serrate, with glands; upper surface pubescent with scattered simple trichomes, stellate trichomes concentrated in midvein, lower surface pubescent, pale, stellate trichomes; venation pinnate, eucamptodromous, secondary veins parallels between them; petiole ca. 2.5 cm long; stipules linear, ca. 1 cm long. Inflorescences 7–22 cm long, terminal, lax, pendant; inflorescence axis flattened, striate; proximal cymules bisexual, with 1 pistillate flower and 1 staminate flower, distal cymules with ca. 2 staminate flowers; bracts entire, linear-lanceolate, ca. 5 mm long, prophylls linear, inconspicuous. Staminate flowers ca. 1.5 cm, subcampanulate, long pedicellate; pedicel ca. 7 mm long; calyx ca. 5 mm long, pubescent externally, greenish-white, stellate trichomes, glabrate internally; calyx lobes 5, united at the base, ca. 4 mm long, entire, equal, valvate, rhomboidal, apex acute to obtuse, margin villose; petals ca. 4 mm long, oblong, apex obtuse, margin villose; disk 5-segmented; stamens ca. 15; filaments filiform, villose at the base, anthers globoseellipsoid; receptacle villose with simple trichomes. Pistillate flowers ca. 1.5 cm long, flask-shaped, pedicellate; pedicels 2–3 mm long; calyx ca. 7 mm long, pubescent externally, ferrugineous at the base, greenish at the apex, stellate trichomes, glabrate internally; calyx lobes 5, ca. 6 mm long, united at the base, entire, equal, quincuncial, rhomboidal, apex obtuse; petals absent; disk 5-segmented; ovary globose, pubescent, stellate trichomes; styles 3, multifid, united into a short column at the base, each one entire half of their length, then branching into ca. 24 terminal arms, exserted from calyx. Fruit ca. 2.5 cm long, ellipsoid, smooth, pubescent; calyx lobes inconspicuously accrescent; seeds ca. 1 cm long, subglobose, ribbed.

Distribution and habitat: —This species occurs in southeastern Brazil, in the states of Minas Gerais, Rio de Janeiro, and São Paulo, in montane rain forests, located at Serras do Mar and Mantiqueira, at 800– 300 m elevation. The collection from the state of Bahia, the lectotype of C. platycladus , would represent an unusual disjunct pattern. However, we found no other collections from Bahia, an indication that perhaps the given locality of the type collection is not correct.

Phenology:— Flowering in October and December; fruiting in January, February, March, April, November and December.

Taxonomic notes: — Croton organensis grows in sympatry with other arborescent species of C. sect. Cleodora , namely C. campanulatus and C. salutaris . However, it is distinguished from them due to its indument (stellate in C. organensis vs lepidote in C. campanulatus and C. salutaris ), leaves (ovate-lanceolate to elliptical in C. organensis vs ovate in C. campanulatus and C. salutaris ) and venation pattern (eucamptodromous in C. organensis vs brochidodromous in C. campanulatus and C. salutaris ).

Most herbaria collections of Croton organensis were lacking staminate flowers in their proximal cymules, because they soon wither and fall. Nevertheless, in the field we have found individuals with bisexual proximal cymules.

Selected specimens examined: — BRAZIL. São Paulo: Campos do Jordão , fl., 26 October 2004, M.B.R. Caruzo et al. 72 (SP, SPF, WIS) .

Figures

FIGURE 5. A–C. Croton organensis. A. Flowering branch, detail of basilaminar gland and serrate foliar margin (Caruzo et al. 72). B. Details of flattened branchlets and stipule (Caruzo et al. 72). C. Pistillate flower (Caruzo et al. 72). D–H. Croton orinocensis. D. Flowering branch, detail of foliar trichomes (Gentry & Berry 14581). E. Stipule (Gentry & Berry 14581). F. floral bract (Gentry & Berry 14581). G. Young fruit (Gentry & Berry 14581). H. Mature fruit (Gentry & Berry 14581).