Croton arlineae Medeiros et al. (2002: 299)

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 : 171

1. Croton arlineae Medeiros et al. (2002: 299) . Type:— BRAZIL. Minas Gerais: Tiradentes, Serra de São José, Cachoeira do Bom Despacho, 21 o 05’S, 44 o 09’W, 28 June 2001 (fl), D. Medeiros 59 (holotype R 000203441!). ( Fig. 1 , A–I)

Subshrubs, 0.4−1 m tall, glabrous. Leaves imbricate and densely congested on branch apices, subsessile with the petiole 0.3 mm long, extremely viscid; leaf blade ovate-lanceolate to lanceolate, 0.5−1.5 × 0.3−0.4 cm, base acute, symmetric, margin punctuate, inconspicuously glandulose, apex acute, glabrous, palminerved; stipules digitate, 3−6-fid, 0.5−0.7 mm long, laciniate-glandulose. Inflorescences with a naked sterile zone between the basal pistillate flowers and the apicalr staminate ones, glabrous; bracts linear-lanceolate, margin entire, 3−3.5 mm long on the staminate flower, 4−4.2 mm long on the pistillate ones, glabrous. Staminate flowers 6−20 per inflorescence; pedicel 1−2 mm long; sepals 5, ovate-lanceolate, 2−3 × 1−1.5 mm, margin entire; petals 5, ovate-lanceolate, 1.5−2 × 0.7−1 mm, margin entire, ciliate; stamens 11, filaments 1−2 mm long, brown, anthers ovoid, 0.5−1 mm long. Pistillate flowers 1−3 at the base of the inflorescence; pedicel 0.7−1 mm long; sepals 5, ovate-lanceolate, 5−6 × 1.5−2 mm, glands on margins and on the adaxial surface, disposed in 3−4 longitudinal rows; petals 5, glanduliform, 0.1−0.4 mm long; ovary globose, 2 × 2 mm, glandulose, glabrous; styles multifid, 3−5 times branched at the base, 1.5 mm long, glabrous. Capsules globose, 4 mm diam., trichomes stellate brownish; seeds ellipsoid, 2.3−2.5 × 2 mm.

Distribution:— Minas Gerais State, Serra do Lenheiro, 1194−1218 m elevation, São João del Rei, and Serra de São José, 1200 m elevation, Tiradentes ( Fig. 2 ).

Additional specimens examined:— BRAZIL. Minas Gerais: São João del Rei, Serra do Lenheiro, 20 January 2003 (fl, fr), D. Medeiros 224 & A.M. Werneck (R), D. Medeiros 225 & A.M. Werneck (R), D. Medeiros 226 & A.M. Werneck (R), D. Medeiros 227 & A.M. Werneck (R), D. Medeiros 228 & A.M. Werneck (R), D. Medeiros 229 & A.M. Werneck (R); 10 July 2004 (fl, fr), D. Medeiros 238 & A.M. Werneck (R), D. Medeiros 239 & A.M. Werneck (R), D. Medeiros 240 & A.M. Werneck (R), D. Medeiros 241 & A.M. Werneck (R), D. Medeiros 242 & A.M. Werneck (R); Tiradentes, Serra de São José, Cachoeira do Bom Despacho, 27 March 2001 (fl), D. Medeiros 31 (R), D. Medeiros 32 (R), D. Medeiros 33 (R), D. Medeiros 34 (R), D. Medeiros 35 (R); March 2001 (fl, fr), D. Medeiros 59 (R), D. Medeiros 61 (R), D. Medeiros 72 (R); Serra de São José, 28 June 2001 (fl) D. Medeiros 51 (R), D. Medeiros 62 (R), D. Medeiros 63 (R); Serra de São José, Cachoeira do Bom Despacho, 24 October 2001 (fl), D. Medeiros 124 (R), D. Medeiros 131 (R); 24 October 2001 (fl), D. Medeiros 133 (R), D. Medeiros 140 (R), D. Medeiros 143 (R); 21 November 2001 (fl), D. Medeiros 174 (R); 22 March 2002 (fl, fr), D. Medeiros 182 (R), D. Medeiros 183 (R), D. Medeiros 184 (R), D. Medeiros 185 (R), D. Medeiros 186 (R); 19 January 2003 (fl, fr), D. Medeiros 214 & A.M. Werneck (R), D. Medeiros 215 & A.M. Werneck (R), D. Medeiros 216 & A.M. Werneck (R), D. Medeiros 217 & A.M. Werneck (R), D. Medeiros 218 & A.M. Werneck (R), D. Medeiros 219 & A.M. Werneck (R), D. Medeiros 220 & A.M. Werneck (R), D. Medeiros 221 & A.M. Werneck (R), D. Medeiros 222 & A.M. Werneck (R); 11 July 2004 (fl), D. Medeiros 244 & A.M. Werneck (R), D. Medeiros 245 & A.M. Werneck (R), D. Medeiros 246 & A.M. Werneck (R), D. Medeiros 247 & A.M. Werneck (R), D. Medeiros 248 & A.M. Werneck (R).

Taxonomic notes:— Croton arlineae is a very distinct species, characterized by the lack of indumentum, and by sepals of the pistillate flowers with glands on margins and on the adaxial surface, disposed in 3−4 longitudinal rows. The leaves are sticky due to the presence of glands and idioblasts with lipophilic content in the parenchyma (Sá-Haiad, pers. comm. 2014).

Figures

FIGURE 1. Croton arlineae. A. Branch; B. Stipule; C. Inflorescence; D. Staminate flower: E. Sepal (dorsal side), F. Petal (dorsal side); G. Pistillate flower: G’. Glanduliform petal; H. Fruit; I. Seed (dorsal side) (after D. Medeiros 33 (R); from Medeiros et al. 2002).

FIGURE 2. Distribution map of Croton arlineae.