Physeterostemon gomesii Amorim & R.Goldenb.,

Amorim, André Márcio, Jardim, Jomar Gomes & Goldenberg, Renato, 2014, Physeterostemon gomesii (Melastomataceae): the fourth species of this endemic genus in Bahia, Brazil, Phytotaxa 175 (1), pp. 45-50: 45-49

publication ID

http://doi.org/ 10.11646/phytotaxa.175.1.5

DOI

http://doi.org/10.5281/zenodo.5149744

persistent identifier

http://treatment.plazi.org/id/77401623-6A56-FFE3-D3E1-F965509CFD85

treatment provided by

Felipe

scientific name

Physeterostemon gomesii Amorim & R.Goldenb.
status

sp. nov.

Physeterostemon gomesii Amorim & R.Goldenb.  , sp. nov. ( Figs. 1View FIGURE 1, 2View FIGURE 2, 3View FIGURE 3)

Diagnosis: ––This species differs from all other species in the genus by its 5-merous flowers, 10 stamens, and 3-locular ovary, as all the other taxa have 6-merous flowers, 12 stamens, and 4-locular ovaries. It differs from Physeterostemon fiaschii  in terms of the latter’s fascicled inflorescences covered with trichomes ca. 5 mm long and calyx with outer lobes 4–5.4 mm long. It differs from P. jardimii  by its habit (rhizomatous subshrubs) and indumentum (strigose but also glandulose-setose in the former), as well as by the ovary apex (setose in P. jardimii  ). It differs from P. thomasii  in terms of its rhizomatous habit by having young stems and petioles covered with paleaceous trichomes and strongly bullate/foveolate leaves.

Type: –– BRAZIL. Bahia: Boa Nova, Parque Nacional de Boa Nova, Fazenda Liberdade , Região da Farofa , BR 030  entre o trecho Boa Nova ao Distrito de Valentim , ca. 5 km de Boa Nova, 14º21’25’’S 40º12’46’’W, 7 February 2013, fl., fr., A. MGoogleMaps  . Amorim, 8170, L. H  . Daneu & L. C. J  . Gomes (holotype CEPEC!, isotypes HURB!, K!, NY!, RB!, UPCB!)  GoogleMaps  .

Shrub40–130(–140)cm tall. Young stems terete,densely strigose, trichomes 1.2–2 mm long, pale green and canescent to ochraceous when dried, appressed, mixed with short (0.1–0.2 mm) glandular projections that are denser in the nodal regions. Leaves opposite, each pair being slightly anisophyllous to isophyllous, petiole 2–4.8 cm long, trichomes the same as on the branches, leaf blade (3.7–)15.2–22.5 × 5.1–11.3 cm, elliptic to elliptic-lanceolate, base acute, apex acuminate to cuspidate, margins irregularly dentate to serrate, ciliate, 3-nerved to shortly 3-plinerved (the inner pair joining the midrib up to 5 mm above the base) with a faint additional submarginal pair, adaxially plane (not bullate), sparsely strigose, trichomes 0.3–0.6 mm long, appressed or with an erect base and strongly curved downward, abaxially plane (not foveolate), moderately strigose (denser on the main nerves), trichomes 0.3–0.6 mm long, erect and curved at the apex, otherwise similar to those on the abaxial surface, mixed with short glandular projections 0.1–0.2 mm long. Inflorescence terminal, corymbose, with 15–45 flowers, 2.6–3.5 × 2.4–4.5 cm, pale green, with trichomes similar to those on young stems; bracts 2.2–2.5 × 0.7–0.9 mm, narrowly triangular, apex acute, glabrous, margin strongly ciliate; bracteoles 1.3–2.2 × 0.3–0.6 mm, narrowly triangular, glabrous, margin strongly ciliate. Flowers 5- merous, pedicels 2–2.6 mm long (up to 4 mm long on the fruits). Hypanthium ca. 2.7 × 2.6–2.7 mm, campanulate, outer surface densely strigose, trichomes ca. 1 mm long, pale green and ochraceous when dried, inner surface and the torus glabrous. Calyx persistent, abaxially strigose, adaxial surface with sparse, short, glandular projections ca. 0.2 mm long; tube 0.3–0.7 mm long; inner lobes 1.2–1.8 mm long, triangular, apex rounded, margin irregular, shortciliate; outer lobes 1.4–1.7 mm long, subulate, setose-tipped. Petals 4.5–4.7 × 3.4–3.6 mm, white, glabrous on both surfaces, obovate, apex truncate to slightly emarginate, margin entire. Stamens 10, isomorphic, grouped together in a cluster on one side of the flower at anthesis; filaments 2.4–2.9 mm long; connective unappendaged, dorsally thickened; anthers 1.7–2 mm long, yellow, oblong, with a rounded apex in ventral view, straight (not slightly projecting backwards over the connective) in lateral view, with a single ventral pore, anthers ventro-basally with two short lobes below the filament insertion. Ovary half-inferior, the free portion 0.8–1 mm long, 3-locular, apex glabrous; ovules many on the large, globose, axial placentae; style curved, stigma punctiform. Capsules 2.9–3.6 × 3.2–3.5 mm, tearing longitudinally, with pericarp and adnate hypanthium persistent, placentae thick, perpendicular to the ovary axis, persistent. Seeds ca. 0.5 mm long, cuneate, testa smooth.

Distribution, habitat, and phenology: ––This species has been collected three times in the same locality in southern Bahia State ( Fig. 1View FIGURE 1). It grows in advanced secondary moist forests, in shaded areas. It has been collected with flowers in January and February and with fruits from the previous season also in February.

Conservation status: — Physeterostemon gomesii  is currently known from only one population (although with many individuals) in the Boa Nova National Park. Habitat fragmentation and the small number of known populations represent high risks for the species. By IUCN (2014) criteria, this species is considered to be Critically Endangered (categories B1a and B1b) as its distribution range is less than 100 km 2, with continually declining habitat quality.

Etymology: ––The new species is named after Luís Carlos de Jesus Gomes, from the CEPEC Herbarium in light of his important technical support for the collections and fieldwork (especially with Melastomataceae  ), and also one of the collectors of the type specimen.

Additional specimens examined (paratypes):— BRAZIL. Bahia: Boa Nova, Parque Nacional de Boa Nova, Setor Sul , Ramal para a Fazenda Liberdade , Setor da Farofa , 14°24’45’’ S, 40°07’46” W, 917m elev., 7 January 2013, fl., L. Y. SGoogleMaps  . Aona , 1988, G. M  . Costa , W. O  . Fonseca , J. G  . Jardim & S  . Simões ( CEPEC, HURB, K); ib., 850m elev., 22 February 2014, fl. fr., R  . Goldenberg 1784, F  . Michelangeli , L. H  . Daneu & L. C. J  . Gomes ( CEPEC, NY, UPCB, RB)  GoogleMaps  .

A

Harvard University - Arnold Arboretum

M

Botanische Staatssammlung München

L

Nationaal Herbarium Nederland, Leiden University branch

H

University of Helsinki

C

University of Copenhagen

J

University of the Witwatersrand

CEPEC

CEPEC, CEPLAC

HURB

Universidade Federal do Recôncavo da Bahia

K

Royal Botanic Gardens

NY

William and Lynda Steere Herbarium of the New York Botanical Garden

RB

Jardim Botânico do Rio de Janeiro

UPCB

Universidade Federal do Paraná

Y

Yale University

S

Department of Botany, Swedish Museum of Natural History

G

Conservatoire et Jardin botaniques de la Ville de Genève

W

Naturhistorisches Museum Wien

O

Botanical Museum - University of Oslo

R

Departamento de Geologia, Universidad de Chile

F

Field Museum of Natural History, Botany Department