Sauvagesia insolita Queiroz-Lima & D.B.O.S.Cardoso, 2017

Queiroz-Lima, Adriana, Amorim, André M. & Cardoso, Domingos B. O. S., 2017, A new species of Sauvagesia (Ochnaceae) from the northern Espinhaço Range, Brazil, and an emended description of Sauvagesia paganuccii, Phytotaxa 316 (1), pp. 59-66 : 60-64

Sauvagesia insolita Queiroz-Lima & D.B.O.S.Cardoso , sp. nov. ( Figs 1–3 )

Type: — BRAZIL. Bahia: Miguel Calmon, Parque Estadual das Sete Passagens, Trilha do Campo Limpo, 11°23’48.1’’S, 40°31’42’’W, 1052 m, 25 September 2015 (fl, fr), A. Queiroz-Lima, D. Cardoso, I. M. Souza & M. F. Fernandes 152 (holotype HUEFS, isotypes ALCB!, CEPEC!, F!, K!, NY!, RB!, SPF!).

The new species is morphologically akin to Sauvagesia paganuccii D.B.O.S. Cardoso & Harley (2015: 777) but differs in its poorly branched, mostly single-stemmed shrubby habit (vs. multi-stemmed, densely branched from the base, subshruby habit), elliptic leaves with a length/width ratio of 2:1 (vs. narrowly elliptic leaves with a length/width ratio of 3:1), leaf margin homogeneously crenulate (vs. margin irregularly crenulate, the crenulae more spaced basally and closer distally), pedicel scars of ca. 20 flowers present along the inflorescence branches (vs. pedicel scars of ca. 70 flowers per inflorescence), and single-apiculate anthers (vs. bi-apiculate anthers).

Shrub up to 1.5 m tall, single-stemmed, poorly branched, the branches erect, slender, cylindrical, glabrous, without leaves at the base. Stipules 5–8 × 1–2 mm, usually caducous at the base of the branches, fimbriate with long, spinescent fimbriae. Leaves spirally arranged, imbricate, usually not exceeding 60° to the branch, petiole very short, ca. 1 mm long, the lamina 4–14 × 3–6 mm, glabrous, chartaceous, glossy, elliptic, length/width ratio 2:1, base rounded, apex obtuse, homogeneously crenulate along the whole margin, marginal vein somewhat swollen, reddish vinaceous on young leaves, margin bearing a conical gland at the base of each sinus, secondary veins in 4 − 8 pairs, curved towards the marginal vein, midrib protruding, thickened at the base and becoming slender towards the apex. Inflorescences paniculate, terminal, 7 − 17 cm long, peduncle 2 − 4.5 cm long, 1 or 2 flowers present at the apices of each racemose axis, pedicel scars of ca. 20 flowers present along the axis; bracts 2 − 4 × 1 − 1.5 mm, foliaceous, glabrous, persistent, bearing glands along the margin; pedicel 3–7 mm long. Flowers pentamerous, opening widely, resulting in a star-like shape, sometimes the petals strongly reflexed distally; sepals 3–4.5 × 1.2–2 mm, vinaceous, glossy, glabrous, elliptic to ovate, glands at the apex and sometimes along the margin, apex acute, base truncate; petals 7–12 × 3–6 mm, reddish pink, glabrous, contorted in bud, ovate, apex acute, sometimes emarginate, margin involute at the apex; free, filamentous external staminodes absent or oddly appearing irregularly in some flowers of the same individual; internal staminodes fused, forming a single corona-like, conical structure, enveloping the stamens, 4.5 − 9 mm long, reddish pink, 5-lobed, each lobe slightly emarginate at the apex; stamens 5, subsessile, borne on short, thick, glabrous filaments, anthers 3 − 4 mm long, orange, conical, apex acute and single-apiculate, introrse, rimose, oblong; gynoecium 6 − 9 mm long, ovary unilocular, subtly trilobed, placentation parietal, style subulate, cylindrical, projecting 1 − 2 mm beyond the apex of the staminodal whorl, stigma inconspicuous. Fruit a septicidal capsule up to 1.5 cm long, brownish, glabrous, ovoid, apex strongly caudate, sometimes with persistent sepals, petals, and anthers. Seeds ca. 1 mm long, 22 − 43 per capsule, dark brown, glabrous, oblong-ovate, apex rounded, muricate.

Paratypes:— BRAZIL. BAHIA: Miguel Calmon, Trilha do Campo Limpo , 11°23’23”S, 40°31’32”W, 1270 m, 7 May 2005 (fl), V. Barreto et al. 36 ( HUEFS) ; ibid., 11°23’50’’S, 40°31’11’’W, 1052 m, 25 September 2015 (fl, fr), D. Cardoso et al. 3817 ( ALCB, CEPEC, HUEFS, RB) ; ibid., without locality, 11°22’19’’S, 40°31’06’’W, 1144 m, 17 June 2006 (st), J. S. Santos et al. 89 ( ALCB) ; ibid., Trilha para a Grota de Dona Antônia , 11°20’S, 40°31’W, 2 August 2006 (fl), J. S. Santos et al. 141 ( ALCB) .

Distribution, habitat, and conservation: — Sauvagesia insolita is probably narrowly endemic to campo rupestre vegetation in Sete Passagens State Park in the northeastern most portion of the Espinhaço Range in Bahia, which lies outside the mountains of Serra do Sincorá in Chapada Diamantina ( Fig. 3 ). The highland rocky grassland where S. insolita occurs is characterized by a mixed vegetation comprising grasses and other angiosperm herbs, as well as subshrubs, shrubs, and sparsely distributed trees. The conservation status of S. insolita is critically endangered (CR) according to IUCN criteria (B2a), due to an area of occupancy (AOO) less than 10 km 2 and extent of occurrence (EOO) less than 100 km 2. However, the only known population of S. insolita is currently protected in a conservation park so its preservation should be guaranteed.

Phenology: — Collections of flowering specimens were made between May and September and fruiting specimens in June and September.

Etymology: — The specific epithet is a reference to the occasional appearance of free external staminodes in the flowers, a previously unreported feature for the species of subsect. Vellozianae .

Taxonomic discussion: — Sauvagesia insolita was hidden in a broad circumscription of the recently described S. paganuccii ( Cardoso & Harley 2015) . In the original description of S. paganuccii, Cardoso & Harley (2015) cited some paratype specimens (Barreto et al. 36, Santos et al. 89, 141) that are, however, newly referred to here as S. insolita . An emended description of S. paganuccii is provided below in the next section. Morphologically, these species have very similar inflorescences and flowers. However, they are clearly distinct on the basis of a unique combination of morphological features that were aforementioned in the diagnosis and summarized in Table 1.

The infrageneric classification of Sauvagesia is still largely based on morphological characters, especially the presence and structure of the staminodal whorls ( Sastre 1981). Accordingly, the absence of external staminodes and the presence of fused, petaloid staminodes resembling a corona are the hallmark of subsect. Vellozianae , a lineage that is nearly endemic to campos rupestres of the Espinhaço Range. Surprisingly, free, filamentous external staminodes were also observed, yet not regularly, in some flowers of S. insolita and S. paganuccii ( Figs 1–2 ). Such an odd character went unnoticed in S. paganuccii ( Cardoso & Harley 2015) , and has never been reported for the species of the genus that have fused staminodes. Why free external staminodes were only observed in a few flowers of the same individual is an interesting question that needs to be further analyzed based on the genetic control of flower development.

The discovery of such transitional features suggests that any consistent placement of Sauvagesia insolita and S. paganuccii in the current infrageneric classification of Sauvagesia should be undertaken with caution until a molecular phylogenetic hypothesis is available for the genus.Meanwhile, despite the irregular presence of free external staminodes, the consistent presence of a corona-like fused staminodal whorl in S. insolita and S. paganuccii places both species in subsect. Vellozianae .

Figures

FIGURE 1. Sauvagesia insolita. A. Branch with inflorescence. B. Leaf, adaxial surface. C. Detail of the leaf margin showing the conical glands. D. Stipule, adaxial surface. E. Flower showing the free, filamentous staminodes external to the corona-like fused staminodal whorl. F. Sepal, adaxial surface. G. Detail of the fused staminodal whorl apex with the protruding style. H. Petal, adaxial surface. I. Dissection of the fused staminodal whorl revealing the stamens and gynoecium. J. Anther, different views showing the single apiculus. K. Fruit with persistent sepals, stamen, and broken staminode. L. Seed. (All from the holotype A. Queiroz-Lima et al. 152 [HUEFS])

FIGURE 2. General morphology and habitat of Sauvagesia insolita. A. An individual showing terminal paniculate inflorescences. B. Detail of an inflorescence showing the short lateral racemes. C. Detail of a flower showing the free, filamentous staminodes external to the corona-like, fused staminodal whorl. D. Dissected flower with sepals, petals, and part of the corona-like petaloid staminode removed to show the stamens and style. E. Detail of the stem showing the spirally arranged leaves and stipules. F. The open grassy campo rupestre vegetation on outcrops where the species was collected. (All photographs by Domingos Cardoso, from the collection A. Queiroz-Lima et al. 152 [HUEFS] at the type locality)

FIGURE 3. Geographical distribution of Sauvagesia insolita and the morphologically similar S. paganuccii in the Espinhaço Range of Brazil.