Bertolonia hirsutissima Bacci, Michelang. & R.Goldenb., 2016

Bacci, Lucas F., Amorim, André M., Michelangeli, Fabián A. & Goldenberg, Renato, 2016, A new species of Bertolonia (Melastomataceae) from southern Bahia, Brazil, Phytotaxa 265 (3), pp. 251-258 : 252-257

Bertolonia hirsutissima Bacci, Michelang. & R.Goldenb. sp. nov. ( Figures 1–3 )

Diagnosis: Bertolonia hirsutissima is an herbaceous Melastomataceae similar to B. wurdackiana Baumgratz (1990: 125) : both have bullate/foveolate leaves with basal nerves, and sepals with similar size. The new species differs by its broadly ovate to cordiform leaves (versus narrowly ovate to broadly elliptical leaves in B. wurdackiana ), hirsute stems and petioles (vs. tomentose), sepals with crenulate-denticulate and long ciliate margins (vs. sepals with lacerate and glabrous margins), anthers lacking an appendage (vs. anthers with a 0.3–0.5 mm long appendage) and thecae dehiscent through an extrorse apical pore (vs. introrse pore).

Type:— BRAZIL. Bahia: Mun. Wenceslau Guimarães, Povoado de Nova Esperança, Estação Ecológica de Wenceslau Guimarães ; trilha do Pico do Urubu, Pedra da Antena , 13º35’15”S – 39º43’09”W, 730 m, 21 February 2014, fl., R. Goldenberg & F. A. Michelangeli 1756 (holotype: CEPEC!) .

Herbs 15–30 cm tall, rupicolous or terrestrial, reptant; adventitious roots branched, growing from several points along the stem, but larger next to its base; stem 5.5–10 mm thick, terete to quadrangular and slightly costate, the older portions aphyllous, the young ones erect and bearing leaves. Young branches, petioles, inflorescences and bracts hirsute, with dense, unbranched, erect to slightly curved glandular trichomes 4–5 mm long (on branches and petioles) or up to 2 mm long (on inflorescences and bracts), gland heads sometimes caducous, and also with sparse to dense, sessile or short-stalked (then less than 0.1 mm long) glands. Leaves opposite, occasionally subopposite; petioles 3.5–10.5 cm long, quadrangular, slightly costate; blade 4.5–13 × 4–9.5 cm, broadly ovate to cordiform, membranaceous, base cordate, apex acute, margins crenulate and ciliate, adaxial surface dark-green, bullate, sparsely covered with sessile glands, otherwise glabrescent, abaxial surface light-green, foveolate, sparsely covered with sessile glands and also unbranched trichomes on the veins (these denser at the base of the primary and secondaries), veins five, plus a shorter marginal pair that do not reach the leaf apex, basal, main veins at the abaxial surface with pocket domatia at their bases. Thyrsoids 10.5–17 cm long, terminal (but pseudo-lateral in older, fruiting specimens), with one pair of paraclades, these cymose, scorpioid, the branches greenish to light-pink; bracts ca. 2 mm long, linear to narrow-lanceolate, then the apex acuminate; bracteoles ca. 1.5 mm long, narrow-lanceolate, apex aristate and tipped with one glandular trichome ca. 0.5 mm long, both surfaces covered only with sessile glands. Flowers 5-merous, on pedicels ca. 1.5 mm long, densely covered with sessile and short-stalked glands. Hypanthium light green, 2–2.7 × 2–2.2 mm, short-terete, 10- costate, with the same indument as the pedicel, seldom with trichomes similar to the ones on the inflorescences. Calyx lacking external teeth, caducous; tube ca. 0.5 mm long; sepals light green, 3–4 × 1.6–1.8 mm, elliptic (the base narrowed), apex rounded to truncate, margins crenulate-denticulate, long-ciliate, both surfaces with sessile and pedicellate glands. Petals light-pink, 10.8–12 × 4.5–5 mm, elliptic, base slightly attenuate, apex acute and apiculate, the apiculus bending outwards (to the abaxial surface of the petal), margins entire, both surfaces papillose. Stamens ten, 6–7 mm long, isomorphic; filaments 3.5–4 mm long, slightly widened at the base; thecae cream-colored, 2–3 mm long, oblong-subulate, slightly undulate, pore apical, extrorse; connective prolonged ca. 1.5 mm below the thecae, lacking appendages, and sometimes slightly dorsally thickened. Ovary free, apex glabrous, 3-locular, placentation axillary; style ca. 5 mm long, curved at the apex, glabrous; stigma slightly capitate, papillose. Capsules bertolonidiumtype (following Baumgratz 1983 –1985), but mature fruits not seen. Seeds unknown.

Distribution, ecology and phenology: — Bertolonia hirsutissima has been collected three times, the first one more than 20 years apart from the latter two, and all from a single locality. The Wenceslau Guimarães Ecological Station is a fully protected area, kept by the Bahia state government, located at the municipality with the same name, coordinates 13°35’43”S and 39°43’10”W (see figure 3). The region is mountainous, ranging from 550 to 1000 m elev., and covered with Atlantic rainforest (“Floresta Ombrófila Densa Submontana/ Montana ”, following the official Brazilian system — Veloso et al. 1991). The area includes a significant proportion of secondary vegetation, but with some patches of mature forest, mostly at higher elevations. The area surrounding the reserve still has some forest cover, but this is very fragmented and frequently disturbed, and there are still large tracts of cocoa ( Theobroma cacao Linnaeus 1753: 782 ) plantations, in which part of the forest is maintained (“cabruca”). The three collections were made on a rocky, shaded wet wall or in “moist tropical forest on steep slope”. The species was collected with flower buds in December, flowers in February and immature fruits in April and December.

Conservation status:—According to IUCN (2014) criteria, this species should be classified as “critically endangered” (CR), since it has been collected in only one locality, despite the fact that the collections were made inside a protected area.

Etymology:— The epithet “ hirsutissima ” refers to the indumentum on the petiole, one of the diagnostic features that identify the new species.

Paratypes:— BRAZIL. Bahia: Mun. Wenceslau Guimarães, ca. 3 km W of Nova Esperança, W edge of Estação Ecológica de Wenceslau Guimarães , 13º36’S 39º43’W, 500-600 m, moist tropical forest on steep slope, 14 April 1992, fr., W. W. Thomas et al. 9285 ( CEPEC!, NY!, RB photo!) ; Estação Ecológica de Wenceslau Guimarães, trilha para Serra Grande ( Mata da Frente ), 13º34’43”S – 39º42’12”W, 500 m, 17 December 2015, fl. bud and fr., L. F. Bacci et al. 273 ( CEPEC!, NY!, UEC!, UPCB!) .

Bertolonia hirsutissima can be recognized by the broadly ovate to cordiform, bullate/foveolate leaves with hirsute petioles, these also with sessile and stalked glands. It also has a short terete hypanthium, long, elliptic sepals with crenulate-denticulate and long-ciliate margins, pink and dorsally apiculate petals, and anthers with thick connectives lacking appendages, prolonged below the thecae, the thecae dehiscent through an extrorse apical pore.

Bertolonia hirsutissima shares the extrorse apical pore with Bertolonia mosenii Cogniaux (1886: 55) , however the latter has a bilobed anther apex that is absent in the new species. Bertolonia alternifolia Baumgratz et al. (2011: 273) has a terminal-dorsal anther pore somewhat similar to the extrorse pore of B. hirsutissima , but it has longer anthers (4.5–6 mm long) with the connective not prolonged below the thecae.

Bertolonia hirsutissima has the same bullate/foveolate leaves as in Bertolonia bullata Baumgratz et al. (2011: 276) , B. foveolata Brade (1956: 226) and B. wurdackiana Baumgratz (see Table 1). From these, the species that seem to be more morphologically similar to B. hirsutissima is B. wurdackiana , endemic of the state of Espírito Santo ( Baumgratz 1990, Baumgratz 2016); both have leaves with basal nerves and sepals with similar size, but B. wurdackiana has narrower leaves (narrowly ovate to elliptic), stems and petioles tomentose, with much shorter trichomes, sepals with lacerate and glabrous margins, and anthers with introrse pores. Bertolonia foveolata is endemic to Espírito Santo ( Baumgratz 2016) and also has hairy stems and petioles, but its trichomes are shorter, the adaxial leaf surface is villose, the sepals much shorter (1.3–2 mm long), and the anthers have introrse pores. Bertolonia bullata is also endemic to Bahia ( Baumgratz et al. 2011), differing from B. hirsutissima due to the narrowly-ovate to elliptic leaves, suprabasal leaves, glandulose-villose petioles, sepals shorter (1.2–1.7 mm long) with entire to undulate margins, and anthers with introrse pores.

It should be noted that the Wenceslau Guimaraes Ecological Station and the immediately surrounding areas constitute the type locality for three other recently described species of Melastomataceae with capsular fruits ( Goldenberg et al. 2016). The description of B. hirsutissima adds a fourth lineage of Melastomataceae for which a new species has been found in this small area, underscoring the need to both preserve these forests and to continue taxonomic and floristic studies in Southern Bahia.

Figures

FIGURE 1. Bertolonia hirsutissima. A) Plant habit with details of the abaxial leaf surface and petiole; B) Inflorescence apex; C) Flower bud; D) Petal with a detail of the apex apiculate, the apiculus bending outwards (to the abaxial surface of the petal); E) Stamen, lateral view; F) Hypanthium, longitudinal section; G) Immature fruit with remnants of the hypanthium wall at the base. Drawn from Goldenberg et al. 1756 (CEPEC) except for G, from Thomas et al. 9285 (NY).

FIGURE 2. Bertolonia hirsutissima. A) Stem and petioles; B) Hirsute petiole with a detail of sessile and stalked gland hairs; C) Adaxial leaf surface; D) Petiole apex and abaxial leaf surface; E) Inflorescence apex; F) Flower bud; G) Vegetation of the “Estação Ecológica de Wenceslau Guimarães”. (A–F by F.A. Michelangeli; G by A.M. Amorim).

FIGURE 3. Map with the collect locality of Bertolonia hirsutissima in the municipality of Wenceslau Guimarães, Bahia, Brazil.