Croton josephinus Müller Argoviensis (1873: 195)

Medeiros, Débora, Valle, Luci De Senna, Esser, Hans-Joachim & Alves, Ruy José Válka, 2016, Floristic and taxonomic treatment of Croton subsect. Medea (Euphorbiaceae) from Brazilian campos rupestres, Phytotaxa 263 (3), pp. 167-201 : 176-178

4. Croton josephinus Müller Argoviensis (1873: 195) . Lectotype (designated by Medeiros et al. 2011):— BRAZIL. Minas Gerais: Tiradentes, Serra de São José, [1430 m elevation], [21 o 05’S, 44 o 09’W], June 1824 (fl), L. Riedel 246 (P 00623256!, isolectotypes G 00386512!, LE!). ( Fig. 7 , A–L)

Subshrubs, 0.5−1 m tall, trichomes stellate, silvery-grey. Leaves concentrated at the branch apices, subsessile with the petiole 2 mm long; leaf blade elliptic-lanceolate, 2.1−4 × 0.6−1.2 cm, base acute, symmetric, margin entire, eglandulose, flat, apex acute, trichomes stellate, dense on both surfaces, penninerved; stipules lanceolate, 2−3 mm long, laciniate-glandulose, trichomes stellate on the adaxial surface, absent on the abaxial one, caducous. Inflorescences 2.5−3 cm long, with a naked sterile zone between the basal pistillate flowers and the apical staminate ones; bracts lanceolate, laciniate-glandulose, 7 mm long on the staminate flowers, 6−7 mm long on the pistillate ones, trichomes stellate on the adaxial surface, absent on the abaxial one. Staminate flowers 7−10 per inflorescence; pedicel 3 mm long; sepals 5, ovate-lanceolate, 2 × 1.2 mm, margin entire, trichomes stellate sparse on the adaxial surface, absent on the abaxial one; petals 5, ovate-lanceolate, 1.8 × 0.8 mm, margin entire, ciliate, glabrous on both surfaces; stamens 10−14, filaments 1−1.5 mm long, densely pilose, anthers 0.7 mm long, ovate, pilose. Pistillate flowers 1−2 per inflorescence; sessile; sepals 5, triangular-lanceolate 7 × 3−3.8 mm, margin stipitate-glandulose, trichomes stellate on both surfaces; petals 5, diminutive, glanduliform, sessile, 0.2 mm long; ovary depressed ovoid, 1.8 × 1.5 mm, trichomes stellate whitish; styles multifid, 2−4 times branched at the base, 1.5−2 mm long, trichomes stellate. Capsules globose, 4.5 mm diam., trichomes stellate greyish; seeds ellipsoid, 2−3 × 2 mm.

Distribution: — Minas Gerais State, endemic to Serra de São José, summit 1430 m elevation ( Fig. 8 ).

Additional specimens examined: — BRAZIL. Minas Gerais: Tiradentes, Serra de São José, Pico 1430 m, 21 o 3’53”S, 44 o 7’50”W, 13 January 2004 (fl, fr), R.A.R. Drummond 169 (R, RB) ; 18 October 2004 (fl, fr), R.J.V. Alves 8345 (R, RB); August 2011 (fl), D. Medeiros 403 (R).

Taxonomic notes: — Croton Josephinus was recently rediscovered ( Medeiros et al. 2011). It is a very distinct species due to its silvery leaf indumentum. Its closest relative is Croton vestitus , from which it can be easily distinguished by its entire and eglandular leaf margin, and its penninerved lamina.

Figures

FIGURE 7. Croton Josephinus. A. Branch; B. Stipule; C. Inflorescence; D. Staminate flower: E. Stamen, F. Sepal (dorsal side), G. Petal (dorsal side); H. Pistillate flower: I. Sepal (dorsal side), J. Gynoecium; K. Fruit; L. Seed (dorsal and ventral sides) (after R.A.R. Drummond 169 (R); from D. Medeiros et al. 2011).

FIGURE 8. Distribution map of Croton Josephinus.