Leandra gynoverrucosa Reginato, 2011

Reginato, Marcelo, 2011, A new species of Leandra (Melastomataceae, Miconieae) from Atlantic Forest, Southeastern Brazil, Phytotaxa 33, pp. 46-50 : 46-49

Leandra gynoverrucosa Reginato , sp. nov. ( FIGS 1A–F , 2A–C )

Leandra gynoverrucosa a speciebus ad sectionem Oxymeris pertinentibus , praesertim nodis prominentibus jugis, foliis conspicuis reticulatis, longe petiolatis et basi decurrentibus, petalorum duplum ad hypantio, antheris apice truncatis macroporosis, hypantio interioribus et ovarium exterioribus parvae glandulosis.

Type:— BRAZIL. Minas Gerais : Itamonte, Serra da Mantiqueira , 1600 m, 8 October 1982, fl., G. G. Hatstchbach, 45546 & R.Kummrow (holotype MBM!, isotype US!) .

Shrub 1 m tall. Branches, petioles, leaves, inflorescences glabrous, but with small pedicellate glands (0.1 mm) on leaf abaxial surface and small translucid glands (0.1 mm) on young buds and inflorescence nodes. Branches terete, nodes with prominent interpetiolar ridges, sometimes projected, encircling the branch. Leaves opposite, isophyllous or slightly anisophyllous in size, in each pair the bigger leaf up to 1.2 times the smaller one; petioles 1.5–3 cm long; blades 5–9 × 2–3.5 cm, ovate to lanceolate, apex acuminate, base acute to slightly decurrent, sometimes slightly asymmetrical, margin slightly serrulate, ciliate (0.7–1.5 mm long), subchartaceous, slightly discolorous in dried material, acrodromous, with 5 main nerves, the inner pair suprabasal, distant 4–11 mm from the base, main veins slightly prominent on abaxial surface, reticulation conspicuous. Thyrses, terminal, up to 10 cm long, up to 7 pairs of opposite paraclades, without accessory branches; flowers on triads, lax, anthopodia 3–12 mm long; bracts two, 1–4.5 mm long, linear to lanceolate, entire; bracteoles two, 0.8–1.2 mm long, lanceolate, entire. Flowers 5-merous, sessile or on pedicels up to 1 mm long. Hypanthium 2.8–3.4 × 2–2.5 mm, campanulate, outside glabrous or sparsely covered by small pedicellate glands (0.1 mm), inner surface covered by the same glands, mainly along the hypanthium veins; torus crenulate, glabrous. Calyx tube 0.2–0.3 mm long; lobes 0.3–0.4 mm long, deltoid, both tube and lobes inside with the same glands as the hypanthium; external teeth 0.6–0.7 mm long, subulate. Petals 6–7 × 1.5 mm, white, linear-lanceolate, cuspidate, entire, eciliate, glabrous, with a dorsal tooth. Stamens isomorphic, glabrous, geniculate; filaments 1.8–2.4 mm long; connectives unappendaged, dorsally produced below the anthers for up to 0.2 mm; anthers 2.4–2.6 mm long, oblong, slightly dorsally arcuate, apex truncate, one apical pore 0.3–0.4 mm wide. Ovary ovate, 2 × 1.5 mm, 1/2 inferior, 3-celled, external surface covered by small pedicellate glands; style ca. 8 mm long, linear, glabrous, stigma punctiform. Fruits and seeds not seen.

Distribution and habitat: Leandra gynoverrucosa is known only from the type collection from Itamonte (44W 52' 11", 22S 17' 03"), state of Minas Gerais, Eastern Brazil. The species was collected on the slopes of the Itatiaia plateau, in the Serra da Mantiqueira. The later is part of the “mar de morros” or seas of hills, a morphoclimatic domain, which includes several ranges of mountains closely paralleling the coastline of southeastern Brazil ( Ab’Sáber 1970). The Itatiaia formation is unique in tropical South America outside the Andes in having a landscape, much of which originated during the Quaternary ( Clapperton 1993, Safford 1999). The species is found in the Atlantic Forest forest understory, at 1600 m above sea level.

Etymology: The specific epithet is an allusion to the ovary surface which is covered by small pedicellate glands.

Leandra gynoverrucosa is likely to belong to the Leandra sensu stricto group due its geographical distribution and shared morphological characters (e.g. habit, petal shape and calyx morphology). Following the traditional sectional circumscription ( Cogniaux 1891), L. gynoverrucosa can be placed in section Oxymeris due its inflorescences that are non glomerulate, non involucrate, neither scorpioid or pseudoaxilary, and hypanthium glabrous or slightly pubescent. The last review of the section Oxymeris was carried out by Cogniaux (1891), which recognized 22 species. Since then a few synonyms and transferals have been proposed ( Wurdack 1962, 1973) and nine new taxa described ( Brade 1956, 1957, 1960; Wurdack 1962; Baumgratz & Souza 2005, 2007, 2009), totaling 29 accepted names for this section.

Leandra gynoverrucosa can be recognized by the prominent interpetiolar ridges, leaves with a conspicuous reticulation, long petioles and a slightly decurrent base, petals twice as long as the hypanthium, anthers with a wide pore equalling the anther’s width, and internal hypanthium and ovary surfaces covered by small pedicellate glands. Leandra quinquedentata (DC.) Cogn. and close relatives (including L. fastigiata Cogn. , L. quinquenodis (DC.) Cogn. , L. neurotricha Cogn. and L. reitzii Wurdack ) seem to be morphologically the closest species to L. gynoverrucosa . They share an overall similar look, especially regarding apparently glabrous structures, since both pedicellate and translucid glands are barely conspicuous under the stereoscopic microscope. Nonetheless, in those species the leaves are usually thicker, the petals are shorter (only as long as the hypanthium in L. quinquedentata or up to half of the size of the hypanthium in L. quinquenodis ), the calyx external teeth equal the internal lobes in size ( L. quinquedentata ) or are bumpshaped ( L. quinquenodis ), the anthers have attenuate apices, the pore is smaller and usually dorsally dislocated, and the hypanthium is internally glabrous and externally usually with sparse dendritic trichomes. Leandra mouraei Cogn. is also morphologically close (as suggested by J.J. Wurdack on a herbarium note in the isotype), sharing indument and leaf features, specially the conspicuous leaf reticulation. However, in this species the interpetiolar ridges are absent, the leaves are thicker, the base is not decurrent and the flowers are different (the torus and the ovary apex bear glandular trichomes, the external teeth are 2 mm long, the petals equal the height of the hypanthium and the anther is minutely pored).

It was observed that Leandra gynoverrucosa has some flowers with the style well developed while the anthers are still incurved in the hypanthium, and young seeds were found in flowers apparently in anthesis. Both features might suggest protogyny in this species and/or apomixis. Unfortunately, reproductive biology data is almost nonexistent in this highly diverse group and field efforts must be increased in order to better understand the evolution of these plants.

Figures

FIGURE 1. A–F. Stereoscope images of Leandra gynoverrucosa, from the holotype. A. Leaf, abaxial view. B. Detail of leaf, abaxial view. C. Nodes showing the prominent interpetiolar ridges. D. Flower. E. Detail of the external surface of the ovary showing the small pedicellate glands. F. Longitudinal section of the hypanthium.

FIGURE 2. A–C. Leandra gynoverrucosa, from the holotype. A. Branch with inflorescence. B. Petal, adaxial view. C. Stamen.