Sinningia × vacariensis (Gesneriaceae) from Southern Brazil, the first natural hybrid described for the genus

Abstract

In this paper we describe and illustrate Sinningia × vacariensis a naturally occurring hybrid between S. lineata and S. macrostachya, from rocky outcrops inside an Araucaria forest in Rio Grande do Sul, Brazil.

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Accepted by Peter Heenan: 16 July 2013; published: 1 August 2013 45
PHYTOTAXA
ISSN 1179-3155 (print edition)
ISSN 1179-3163 (online edition)
Copyright © 2013 Magnolia Press
Phytotaxa 119 (1): 45–50 (2013)
www.mapress.com/phytotaxa/Article
http://dx.doi.org/10.11646/phytotaxa.119.1.4
Sinningia × vacariensis (Gesneriaceae) from Southern Brazil, the first natural
hybrid described for the genus
GABRIEL EMILIANO FERREIRA1, JORGE LUIZ WAECHTER1 & ALAIN CHAUTEMS2
1Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Botânica, Av. Bento Gonçalves, 9500, Porto Alegre,
Rio Grande do Sul, 91501-970, Brazil. E-mail: gabriel_efs@yahoo.com.br, jorgew@brturbo.com.br.
2Conservatoire et Jardin botaniques de la Ville de Genève, Case postale 60, CH-1292 Chambésy, Suiça.
E-mail: Alain.Chautems@ville-ge.ch.
Abstract
In this paper we describe and illustrate Sinningia × vacariensis a naturally occurring hybrid between S. lineata and S.
macrostachya, from rocky outcrops inside an Araucaria forest in Rio Grande do Sul, Brazil.
Resumo
Neste trabalho, descreve-se e ilustra-se Sinningia × vacariensis, um híbrido natural entre as espécies S. lineata e S.
macrostachya, ocorrendo em afloramentos rochosos no interior da floresta com Araucária no Rio Grande do Sul, Brasil.
Key words: Gesneriaceae, rocky outcrop, hybridization, clade Dircaea
Introduction
Hybrids between species of the Gesneriaceae family are easy to produce and numerous crosses were obtained
by horticulturists and plant growers as appears in the list kept by the Gesneriad society (http://
www.gesneriadsociety.org/ir_ges/index.htm). Interspecific hybrids also have been used in an effort to delimit
cenospecies and improve classification within the genus Sinningia Nees (1825: 297) (Clayberg 1996).
Naturally occurring hybrids can also occur, but are rarely reported (Puglisi et al. 2011). In Brazil some
hybridization events were strongly suspected, based on morphological observation in the field or on
herbarium specimens for Nematanthus Schrader (1821: 718) (Araujo et al. 2005, Chautems 1988, Chautems
& Kiyama 2003) and Vanhouttea Lemaire (1845: 346) (Chautems 2002, SanMartin-Gajardo 2005).
For Sinningia, a few examples of individuals intermediate between two parent species were observed in
the field (Chautems, pers. obs.), but never formally registered or published. A first case is here documented
involving two species of this genus that counts over 60 species of shrubs, sub-shrubs or tuberous herbs
occurring in a broad range of geographic regions and growing under distinct ecological conditions (Araújo &
Chautems 2012, Chautems 2010). Based on morphological studies of herbarium, living material and field
studies, we describe a new hybrid species between S. lineata (Hjelmquist 1937: 302) Chautems (1990: 385)
and S. macrostachya (Lindley 1828: 1202) Chautems (1990: 386), from rocky outcrops inside an Araucaria
forest in Rio Grande do Sul, Brazil.

FERREIRA ET AL.46 • Phytotaxa 119 (1) © 2013 Magnolia Press
Sinningia × vacariensis Ferreira, Waechter & Chautems nothosp. nov. Fig. 1 A–F
Type:—BRAZIL. Rio Grande do Sul: Vacaria, Afloramento rochoso no interior da Floresta com Araucária, próximo ao
Rio Pelotas, 28°12’42”S, 50°45’35”W, 660 m, 18 November 2012, G.E. Ferreira and C.Vogel-Ely 235 (holotype
ICN, isotype G).
FIGURE 1. A–F. Sinningia × vacariensis (from the holotype). A. Habit. B. Ovary with calyx. C. Corolla opening, front view. D.
Calyx with corolla. E. Corolla without calyx and trichomes. F. Anthers details with front view.

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SINNINGIA × VACARIENSIS FROM SOUTHERN BRAZIL
Plants rupicolous with erect stems arising from tubers; Stems 80–100 cm long, pilose, green with reddish
streaks. Leaves opposite-decussate, subequal, petiole 1.5 cm long, tomentose, concolorous; blade ovate–
elliptic, 8–15 cm long, 7–12 cm wide, obtuse at the apex, cordate or sometimes unequal at the base, margin
irregularly crenate, 4–5 pairs of veins, above strigillose, below whitish-tomentose. Inflorescences cymose,
composed of pair-flowered cymes, borne in the axils of bracts or upper leaf pairs over the ca. 30 cm long apex
of the axis; peduncles 0.5–2 cm long, green with reddish streaks, hirsute; pedicels ascending 0.5–2 cm long,
green with reddish streaks, hirsute. Calyx ovate, tube 2–3 mm long, hoary-tomentose, lobes linear-lanceolate,
4–6 mm long, acuminate, margin entire, green, pilose. Corolla erect in calyx, tubular, 2.5–3 cm long, red,
pilose, base with 5 gibbosities between the calyx lobes, tube constricted above base, 3–4 mm wide, then
expanding gradually to 5–7 mm wide at throat, limb spreading, lobes 5, with many dark red dots, unequal, ca.
4 × 4 mm; Stamens 4, included, filaments 2.9–3.2 cm long, glabrous, anthers coherent, rectangular, pollen
white, nectary consisting of two separate dorsal glands; Ovary 6 mm long, 2 mm wide, hispid, style 2 cm
long, green, pubescent. Fruit a dry two-valved capsule, 0.9–1.1 cm long, and 0.4–0.6 cm wide, acuminate,
reddish brown, pubescent; seeds narrowly ellipsoid, brown.
FIGURE 2. Distribution of Sinningia macrostachya, S. lineata and S. × vacariensis in South America, showing the overlapping area.
Blue circle. S. macrostachya. Red triangle. S. lineata. Pink lozenge. S. × vacariensis.

FERREIRA ET AL.48 • Phytotaxa 119 (1) © 2013 Magnolia Press
Distribution and habitat:—This hybrid occurs in the Vacaria municipality in Rio Grande do Sul, next to
the Pelotas River. We located only one individual, growing on basaltic rock outcrops within an Araucaria
forest, close to streams or in shaded habitats, between 600 and 800 m in elevation (Fig. 2).
Etymology:—The name of the nothospecies is derived from the municipality “Vacaria” where the plant
was first encountered.
FIGURE 3. A–F. Comparison between the two species and the hybrid. A–B. Sinningia macrostachya. A. Habit. B. Detail of flower.
C–E. S. × vacariensis. C. Habit. D. Detail of inflorescence. E. Detail of flower F–G. S. lineata. F. Habit. G. Detail of flower.

Phytotaxa 119 (1) © 2013 Magnolia Press • 49
SINNINGIA × VACARIENSIS FROM SOUTHERN BRAZIL
Discussion
In the framework of a taxonomic and biogeographic survey of tribe Sinningieae in Rio Grande do Sul we
came across a plant that drew our attention by its inflorescence and flower structure intermediate between S.
lineata and S. macrostachya, (Fig. 3 A–F). Detailed observations led us to conclude that we had found a case
of natural hybrid between these species.
As for morphological characters, S. macrostachya has opposite leaves, ovate to elliptic, 8–15 × 5–9.5 cm,
petiole 2.5 cm, distributed in 4–7 whorls, (frondo)-bracteose florescence with cymes (Chautems & Weber
1999), peduncle up to 1 cm, corolla 2.8 cm, orange to red, with few vinose dots mostly on ventral and lateral
lobes. S. lineata has opposite leaves, elliptical to ovate, 9.5–15 × 7–14 cm, disposed in 1–2 whorls, petiole 4.5
cm, shoot reduced to frondose florescence with a well-developed pair-flowered cymes (Chautems & Weber
1999), peduncle 7–15 cm, corolla 2.8–3.5 cm, orange to reddish, all lobes with vinose dots. S. ×vacariensis
clearly presents morphological characteristics intermediate between the two species: leaves opposite-
decussate, ovate to elliptic, 8–15 × 7–12 cm, distributed in 3 whorls, petiole 1.5 cm long, frondo-(bracteose)
florescence with cymes, peduncle 0.5–2 cm long, corolla 2.5–3 cm long, lobes with vinose dots on ventral and
lateral lobes and dark red dots on dorsal lobes.
S. macrostachya is a species that has a rather wide distribution in southern Brazil and a neighbouring area
in Uruguay (Grela & Brussa 2005), occurring in sunny rock outcrops from sea level to an altitude of 1000 m,
whereas S. lineata has a restricted distribution, occurring in shaded rock outcrops in the forests and steep
slopes along the Pelotas, Canoas, Uruguay and Antas rivers. As both species inhabit different environments,
the likelihood of hybridization can be considered as low. However, the hybrid S. ×vacariensis was collected
where the areas of occurrence of the two species overlap, on a rocky outcrop within a forest, at the mouth of
the Socorro River, which flows into the Pelotas River). At this site, the two habitats of both parental species
are in close proximity (ca. 300 m). Probably this hybrid has originated from cross-pollination by
hummingbirds, since the two species have the same pollination syndrome. This hybridization event is not
surprising as the two parent species are phylogenetically closely related as inferred from their sister position
within clade Dircaea in recent molecular studies (Perret et al. 2003, 2007).
Acknowledgements
We are grateful to Capes (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) for providing a
scholarship to the first author, to Juliana Allgayer for her great help during the field expeditions, to Alan
LaVergne for revising the text and to Dr. Mathieu Perret for kindly producing the distribution map. We are
also grateful to the Editor and the Reviewer for their valuable suggestions on the submitted manuscript.
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