Croton fragrantulus Croizat (1944a: 466)

Caruzo, Maria Beatriz Rossi & Cordeiro, Inês, 2013, Taxonomic revision of Croton section Cleodora (Euphorbiaceae), Phytotaxa 121 (1), pp. 1-41 : 24

12. Croton fragrantulus Croizat (1944a: 466) . Croton paniculatus Müller Argoviensis (1865: 87) nom. illeg. ( Fig. 3A–E ). Type:— PERU. prope Chacahuani, s.dat., J.A. Ruiz s.n. (holotype G, isotype P!).

Treelets 5–6 m tall; stellate, multiradiate and appressed-stellate trichomes; branchlets cylindric, young branchlets flattened, conspicuously striate, pubescent, pale multiradiate trichomes. Leaves slightly discolorous, with a pair of sessile saucer-shaped acropetiolar glands; lamina 4.5–11 × 3–8 cm, ovate, apex acute to acuminate, base cuneate to slightly truncate, margin minutely serrate, with glands; upper surface glabrescent, scattered stellate and appressed-stellate trichomes, lower surface pubescent, stellate and appressed-stellate trichomes, rarely multiradiate; venation pinnate, brochidodromous; petiole 1–3 cm long; stipules linear, ca. 1 mm long, deciduous. Inflorescences 5–14 cm long, terminal, lax, apparently branched; inflorescence axis flattened, conspicuously striate, pubescent, multiradiate trichomes; proximal cymules bisexual, with 1 pistillate flower and 1–2 staminate flower, distal cymules with 2–3 staminate flowers; bracts ca. 3 mm long, entire, linear; prophylls ca. 1 mm long, linear. Staminate flowers ca. 6 mm long, subcampanulate, pedicellate; pedicels ca. 2 mm long; calyx ca. 4 mm long, pubescent externally, pale multiradiate trichomes, glabrate internally; calyx lobes 5, united up to half of their length, then free for the terminal ca. 2 mm, entire, equal, slightly imbricate, broadly ovate, apex acute, margin villose; petals ca. 4 mm long, narrow-ovate, apex rounded, villose externally, simple trichomes, glabrate internally, margin villose; disk 5-segmented; stamens ca. 15, filaments subulate, villose, simple trichomes, anthers ellipsoid; receptacle villose with simple trichomes. Pistillate flowers 6–8 mm long, campanulate, pedicellate; pedicels 2–3 mm long; calyx ca. 4 mm long, pubescent externally, pale stellate and multiradiate trichomes, glabrate internally; calyx lobes 5, united up to half of their length, then free for ca. 2 mm, entire, equal, slightly imbricate, narrow-ovate, apex acute to acuminate, margin villose, creased at the base; petals absent; disk entire, deeply 5-lobed; ovary subglobose, pilose, multiradiate trichomes; styles 3, 4-fid, united at the base, each one entire half of their length then branching into 12 terminal arms, covered by multiradiate trichomes, exserted from calyx. Fruits not seen.

Distribution and habitat: —The species has a disjunct distribution between Peru, where it occurs in the Andean valley in Huánaco region, and Bolivia, in the Chiquitana region, in dry forests, at 400–600 m elevation. In Peru, it is only known by its type-collection.

Phenology:— Flowering in October and November.

Taxonomic notes: — Croton fragrantulus is most similar to C. rottlerifolius , but the two species can be differentiated mainly by the morphology of branchlets, inflorescence axis and staminate flowers calyx lobes (see table 2).

On the type-collection deposited at the Herbarium of the Museum (P), the annotated collector is Pavon s.n. not Ruiz s.n., as written by Müller Argoviensis on the protologue of Croton paniculatus . Even though, we believe that collection is a duplicate from the holotype deposited at Geneva Herbarium (G) seen by Müller Argoviensis and used by him to describe that species.

Selected specimens examined: — BOLIVIA. Santa Cruz: Nuflo Chaves, 14 km (by air) NW of San Javier, gap through range and slope on west side, Las Lajas , “El Chupadero”, 16º10’S, 62º36’W, fl., 30 November 1990, M. Nee 40099 (NY, WIS) .

Figures

FIGURE 3. A–E. Croton fragrantulus. A. Flowering branch, detail of the acropetiolar glands (Nee 40099). B. Pistillate flower (Nee 40099). C. Disk at the base of the gynoecium (Nee 40099). D. Staminate flower (Foster 424). E. Stamen, dorsal and ventral views (Foster 424). F–I. Croton hemiargyreus. F. Flowering branch, detail of the acropetiolar glands and serrate foliar margin (Caruzo et al. 116). G. Pistillate flower (Caruzo et al. 116). H. Gynoecium and reduced petal (Caruzo et al. 116). I. Fruit (Caruzo et al. 114).