Mitracarpus federalensis E. L. Cabral, Sobrado & E. B. Souza, 2013

Cabral, Elsa L., Sobrado, Sandra V. & Souza, Elnatan Bezerra de, 2013, Three new species of Mitracarpus Zucc. (Rubiaceae) from Brazil, Candollea 68 (1), pp. 139-146 : 140-145

Mitracarpus federalensis E. L. Cabral, Sobrado & E. B. Souza , spec. nova ( Fig. 4 ).

Typus: BRASIL. Distrito Federal: APA Gama e Cabeça de Veado , ARIE do Córrego do Cedro , R. A. do Núcleo Bandeirante , 15º54’00.5’’S 47º57’16.0’’W, 23.IV.2003, fl fr, M. L. Fonseca & D. Alvarenga 4582 (holo-: IBGE; iso-: CTES!).

Mitracarpo eitenii affinis, sed ab eo habitu maiore 50- 60cm alto(vs 15-50 cm), glomerulisfloralibus terminalibus et axillaribus minoribus, 8-12 mm in diametro, aequalibus (vs 13-20 mm diam., et terminalibus majoribus quam axillaribus), 2(-4) bracteis involucralibus (vs 2-8), lobis calycis longioribus 2-2.5 mm (vs 3-4 mm) longis, tubo corollae 4-4.6 mm longo, intertiosuperiorepilishyalin is instructo, lobis corollinis apice pilosis extus pilis purpureis confertis pilosi intus papillosi (vs 3-4 mm longis, tubo puberulo, lobis tantum dense puberulis), seminibus 0.7 × 0.5 mm, reticulatis (vs 0,8 × 0,6 mm, laevibus), differt.

Branched, erect or scandent herb, 50-60 cm tall, lateral branches opposite. Stems quadrangular, 1-2 mm broad, densely pubescent on young branches and near the glomerules, internodes 7-13 cm long. Leaves 22-33 × 5-8 mm, lanceolate, chartaceous, apex acuminate, margins revolute, scaberulous, both surfaces puberulous, main nerves pilose on the lower surface, secondary nerves obscure; stipular sheath 2-3 mm long, subtriangular, covered with hyaline hairs, bristles 5-6, 1.5-3(-3.5) mm, linear, glabrous. Inflorescence a terminal glomerule, 8- 12 mm wide, globose, multi-flowered, 2-3 axillary glomerules also present; involucral bracts 2(-4), foliaceous, 15-20 × 4-5 mm, twice the length of the glomerule, violet at the base, puberulous on both faces. Flowers pedicellate, pedicels 0.7-1 mm long, hyphantium 1-2 mm long, obconical, puberulous; calyx 4-merous, 2 large lobes, 2-2.5 mm long, half as long as the corolla tube, carinate, margins ciliate, greenish, the base brown; 2 small lobes, 1-2 mm long, triangular, ciliate; corolla white, 5.5-6 mm long, infundibuliform, tube 4-4.6 mm long, the exterior with trichomes in the upper part, the interior with moniliform hairs in the lower third, lobes 1-1.5 mm long, the outer surface with a tuft of purple hairs, inner surface papillose. Stamens sessile, anthers ca. 1 mm. Style 1.5(-5.5) mm long, style-arms 0.6-1.5 mm long. Capsule 1.5 × 2 mm, globose, glabrescent. Seeds obovoid, 0.7 × 0.5 mm, brown, the ventral face with an X-shaped groove, which is densely covered with granular excrescences, the dorsal face lacking both a central depression and angular depressions caused by extensions of the ventral groove, the testa irregulary reticulatepapillate ( Fig. 3 E-I).

Distribution and habitat. – Brazil, Distrito Federal. This species grows in an area with flat relief, red laterite soil and a small strip of degraded cerrado lying between the highway and railway at an altitude of 1030 m.

Notes. – Mitracarpus federalensis is characterized by the ventral face of the seeds having an X-shaped groove and the dorsal face lacking a depression. Given that the species does not possess seeds with a cruciform dorsal depression (like as M. baturitensis Sucre or M. frigidus (Roem. & Schult.) K. Schum. ) nor semicircular dorsal depressions (like as M.longicalyx E. B. Souza & M. F. Sales ), it is clearly related to M. eitenii E. B. Souza & E. L. Cabral. However , it differs from that species by its habit, the size and development of the inflorescence and the size and indumentum of the flowers and seed surface.

Paratypi. – BRAZIL. DistritoFederal: APA Gama e Cabeça de Veado , 15º45’38.3’’S 47º57’26.3’’W, 23.IV.2003, M. L. Fonseca & D. Alvarenga 4565 ( CTES, IBGE); 15º54’48.9’’S 47º57’50.2’’W, 29.IV.2003, M. L. Fonseca & D. Alvarenga 4620 ( CTES, IBGE) .

Figures

Fig. 4. – Mitracarpus federalensis E. L. Cabral, Sobrado & E. B. Souza. A. Habit; B. Stipular sheath; C. Leaf-blade; D. Flower; E. Corolla; F. Hypanthium, calyx, style and stigma; G. Dehiscent fruit; H-I. Seed; H. Dorsal view; I. Ventral view. [A: Fonseca & Alvarenga 4620,CTES; B-I: Fonseca & Alvarenga 4582, IBGE] [Drawing: L. Simón]

Fig. 3. – Seed morphology (SEM-graphs). Mitracarpus carajasensis E. L. Cabral, Sobrado & E. B. Souza: A. Ventral view; B. Lateral view, notice the extensions of the ventral groove and the dorsal face depression; C. Dorsal view; D. Detail of reticulate-foveate testa. Mitracarpus federalensis E. L. Cabral, Sobrado & E. B. Souza: E. Ventral view; F. Lateral view, notice the extensions of the ventral groove; G. Dorsal view; H. Detail of testa of the lateral face, showing the hydrated papillas; I. Detail of testa of the dorsal face, showing the dehydrated papillas. Mitracarpus fernandesii E. L. Cabral, Sobrado & E. B. Souza: J. Ventral view; K. Lateral view, notice the extensions of ventral groove and dorsal depression; L. Dorsal view; M. Detail of reticulate-areolate testa of the dorsal angle; N. Detail of reticulate testa of the dorsal depression [Scale bars: A-C, E-G, J-L: 0.25 mm; D, H-I, M-N: 50 µm]. [A-D: Giorni & al. 196, BHCB; E-I: Fonseca & Alvarenga 4582, IBGE; J-N: Souza & al. 1737, HUV]