Prepusa dibotrya Fraga, A. P. Fontana & L. Kollmann 2014, sp. nov.
Creators: name: Fraga, Claudio Nicoletti De
name: Fontana, André Paviotti
name: Kollmann, Ludovic Jean Charles
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Gentianales
Gentianaceae
Prepusa
Prepusa dibotrya

description: Prepusa dibotrya Fraga, A.P. Fontana & L. Kollmann, sp. nov. (Figures 1, 2)
The new species resembles Prepusa viridiflora Brade, but differs by obtuse or rounded leaf apices, a wine-brown corolla that is usually longer than the calyx, and two morphological features new to the genus: compound inflorescences (dibotryum), and flowers with villous stigma.
Type: — BRAZIL. Espírito Santo: Santa Teresa. Pedra da Onça, 19 o 53’55”S and 40 o 48’56”W, 900 m elev., 16 Jan 2013 (fl), L. Kollmann, A.P. Fontana, C.N. Fraga, E.J. Lirio, V. Sarnaglia 12598 (holotype: MBML!; isotypes: BHCB!, CEPEC!, HUEFS!, K!, MBM!, MO!, NY!, P!, RB!, SPF!).
Herbs, woody at the base, 29–43 cm tall without the inflorescence, branched at the base. Stems cylindrical 3.6–8.3 mm diam., internodes 3.8–28.7 mm long at the base, pale yellowish to castaneous, thereafter quadrangular 4.1–8.8 mm long, winged, internodes 6.3–140.5 mm long in the leafy part and below inflorescence, greenish-castaneous to dark wine-coloured. Leaves elliptic-oblong to narrowly elliptic, oblanceolate, 60.5–160 × 18.8–45.2 mm, oppositely crossed, base attenuate to connate-perfoliate only at the base, colleters internal, margins straight to slight revolute, apex obtuse to rounded, sometimes mucronulate; adaxial surface sulcate to conduplicate at the base, darkgreen to wine-coloured at the apex, abaxial surface carinate in the midvein at the base, greenish, 2–5 pairs of secondary veins greenish to white. Inflorescence compound, dibotryum, erect, 2–5 botryoid paraclades, 15–53- flowered, cylindrical 190–320 × 1.8–5.5 mm, internodes 20–165 mm long, wine-coloured; botryoid paraclades ending in triads, erect, 3–9-flowered, cylindrical, 2–135 × 1–3.1 mm, internodes 2–130 mm long, wine-coloured; bracts elliptic, obelliptic, obovate or oblanceolate, 7–45 × 3–26 mm, connate-perfoliate only at the base, colleters internal, margin straight to slight revolute, apex obtuse to rounded, sometimes mucronulate; adaxial surface sulcate to conduplicate at the base, dark-green to wine-coloured at the apex, abaxial surface carinate in the midvein at the base, greenish, 2–3 pairs of secondary veins greenish to white; bracteoles 1 pair per flower, inserted at 1/5–4/5 of the pedicel length (from the base), terminal flower commonly lacking subtending bracteoles, oblanceolate, narrowly elliptic or oblong, 2.5–7 × 0.5–2 mm, base attenuate to connate, apex mucronate, green to wine-coloured at the apex; pedicel cylindrical, 25–50 × 0.7–1.3 mm at anthesis, to 45–60 × 1–1.5 mm during fruiting, green to wine-coloured at the apex. Calyx campanulate, 20–30 mm at anthesis, to 30–38 mm during fruiting, papillose internally and externally, dorsally winged, yellowish-green to paleaceous when old; wings 0.8–3.7 mm wide, reaching the base of the calyx lobes; lobes triangular, 6–10 × 5–8.6 mm at anthesis, to 6.5–10.3 × 5–8.6 mm during fruiting, apex acute. Corolla funnel-shaped, longer than the calyx, 2.3–38 mm long, 4.8–7.2 mm diam. at mouth, tube 6.5–9 mm long, 3–4.9 mm diam. at base, 3–4 mm wide below filament insertion; lobes lanceolate, 10–12 × 4.3–5.2 mm, margin slightly crenulate, apex acute or acuminate, cream to brown-purplish in the upper half, yellowish-green in the lower half to whitish at the base. Filaments almost equal in length, not twisted when dry, 10.4–13.6 mm long; anthers 4–4.1 mm long, attached to filaments 1–1.1 mm long from the anther base. Ovary 7.8– 9.2 mm long; style 8.4–9.7 mm long; stigma lobes obovate, villous on adaxial surface, 2.2–3 mm long. Capsule dehiscent, 11–18 mm long; seeds 0.1 mm.
Phenology: —Collected in flowers from August to January and flowers/fruits from March to April.
Etymology: —The specific epithet of the new species refers to its dibotryum inflorescences, a distinguishing character for this species.
Distribution, habitat and ecology: —The new species is endemic from Pedra da Onça, Santa Teresa, Espírito Santo. This region is characterized by granitic and gneissic inselbergs that are frequently dome-shaped and rise more or less abruptly above the surrounding landscape and limited by the border of Tropical Semideciduous Forest. Geologically and geomorphologically they form old landscape features that are widespread on the crystalline continental shields, and are particularly abundant in certain tropical regions. The inselbergs of southeastern Brazil have been recognized as one of the three top hotspots of inselberg plant diversity, due to their species richness and high levels of endemism (Porembski, 2007). The habitat of Prepusa dibotrya is characterized by rather sparse vegetation, with thickets of shrubs among a herbaceous layer that usually fades in the dry season.
Conservation: —Due to the apparent rarity, restricted distribution, and vulnerability to human activities, we include this species in the critically endangered category of the IUCN Red List of endangered plant species (IUCN, 2001), in accordance with the following criteria [EN B1ab(i,iii,iv)].
Additional specimens examined (paratypes):— BRASIL. Santa Teresa, Pedra da Onça, 19 o 53’54.2”S and 40 o 48’56.3”W, 975–1029 m elev., 8 Mar 2009 (fl/fr), M.D.S. Demuner & S. Venturini 59 (MBML!); 25 Apr 2009 (fl/fr), M.D.S. Demuner & A.M. Assis 90 (MBML!); 10 Aug 2009 (fl), M.D.S. Demuner & H. Loss 122 (MBML!).
Affinities: — Prepusa dibotrya has two morphological features new to the genus: compound inflorescences (dibotryum) and flowers with villous stigma in a genus otherwise predominantly known for its simple inflorescences and smooth or verrucose stigma. By the characters of its stems, not woody (herbaceous), or woody only at the base (subshrub), its yellowish-green or greenish-brown calyx, dorsally winged, wings reaching the base of the calyx lobes, its stems not woody (herbaceous) or woody only at the base (subshrub), the new species to some extent resembles Prepusa viridiflora Brade.
However, this new species differs from the latter by stems that are cylindrical at the base yet merging to quadrangular (vs. cylindrical), leaf apices obtuse or rounded (vs. acuminate or acute), inflorescences compound, dibotryum, (vs. simple), bract apices obtuse to rounded, sometimes mucronulate (vs. acute or acuminate), calyces papillose on the inner and outer surface (vs. papillose only on the inner surface), corollas wine-brown, usually longer than the calyx, with lobes lanceolate, and apices acute or acuminate (vs. green, usually the same size as the calyx, with lobes widely ovate, and apices caudate), filaments less than 20 mm long (vs. more than 20 mm long), anthers attached to the filament 1–1.1 mm from the anther base (vs. anthers attached to the filaments 1.7–2.1 mm from the anther base), ovaries less than 10 mm long (vs. more than 10 mm long), styles less than 10 mm long (vs. more than 10 mm long), stigmas with villous obovate lobes (vs. stigmas with verrucose lobes, very widely ovate or oblong). Additional diagnostic characters are presented in Table 1.
Both species are endemic to Espírito Santo and are restricted to saxicolous vegetation islands on inselbergs with outcropping granitic and gneissic rocks, and do not occur in sympatry with any other Prepusa species. They are fairly isolated from each other, and their geographic distribution does not overlap. Prepusa dibotrya was collected in the northwestern mountainous region of the state, in regions near the Tropical Semideciduous Forest, at elevations between 900–1030 m, in areas continuously subject to drought, whereas P. viridiflora occurs in the southern mountainous region of the state, in areas next to the Tropical Ombrophilous Forest, at elevations of 1100 to 1600 m above sea level (see Annex), with higher humidity levels, but remaining subject to drought due to the thin soil cover (Figure 3).
description: Published as part of Fraga, Claudio Nicoletti De, Fontana, André Paviotti & Kollmann, Ludovic Jean Charles, 2014, A new species of Prepusa (Helieae, Gentianaceae) from the Brazilian Atlantic Forest, with an emended key for the genus, pp. 287-294 in Phytotaxa 163 (5) on pages 288-291, DOI: 10.11646/phytotaxa.163.5.4, http://zenodo.org/record/5132495