Stigmatodon lemeanus D.R.Couto, A.P.Fontana & Fraga, 2023

Couto, Dayvid Rodrigues, Fontana, Andre Pavioti, da Costa, Andrea Ferreira & de Fraga, Claudio Nicoletti, 2023, A new epilithic bromeliad (Stigmatodon, Tillandsioideae) from Pedra dos Tre ̂ s Ponto ̃ es, Espi ́ rito Santo, Brazil, with an emended combination for the genus, Plant Ecology and Evolution 156 (2), pp. 215-224 : 215

Stigmatodon lemeanus D.R.Couto, A.P.Fontana & Fraga sp. nov.

Figs 1 , 2 , 3 , 4

Type.

BRAZIL - Espírito Santo • Afonso Claudio , Pedra dos Três Pontões, inselberg, epilithic on vertical rock wall; 20°04 ’33” S, 41°02 ’39” W; 1078 m; 21 Oct. 2019; fl.; D.R. Couto & C.N. Fraga 4926; holotype: MBML [MBML055811]; isotype: RB .

Diagnosis.

Similar to Stigmatodon goniorachis (Baker) Leme, G.K.Br. & Barfuss but distinguished by the suberect to patent peduncle (vs erect to suberect) that is more robust with a diameter of 6.5-7.8 mm (vs 3.5-6.2 mm), the main axis with shorter internodes (8.5-9.5 mm vs 15-25 mm long) that supports fewer flowers (11-13 vs 14-32), the longer flowers (56-60 mm vs 35-40 mm long), the larger petals (38-39 × 17-21 mm vs 22-28 × 13-15 mm), the basal appendages with irregularly acute-dentate apex (vs irregularly bidentate), and the shorter stamens (19-22 mm vs 26-28 mm long).

Description.

Lithophytic herb, 50-67 cm tall when flowering, propagating by basal shoots. Stem long, creeping, 7-20 cm in length. Leaves 12-20 in number, rosulate, thickly coriaceous, forming a funnelform rosette; sheath elliptic, 10-14 × 6-8.5 cm, densely and minutely castaneous-lepidote on both sides; blade narrowly triangular, apex acuminate-caudate, recurved, flat, suberect to arcuate, (11-)17-20 cm long, 2-2.8 cm wide at the base, green on both sides and usually with purplish-vinaceous spots on the adaxial side, usually vinaceous along margins, densely white-lepidote on both sides, with trichomes forming white crossbands adaxially, not obscuring the green colour of the blade, margins truncate, ca 0.5 mm thick. Inflorescence simple, ascending, 14-17 cm long, apex obtuse before and at anthesis, 11-13 flowered; peduncle suberect to patent, 35-42 cm long, 6.5-7.8 mm in diameter, green, glabrous, smooth at anthesis, sulcate in sicco; peduncle bracts subfoliaceous at the base, ovate above, apex obtuse-acuminate to apiculate, 2.5-3.5 × 2.4-2.8 cm, erect, imbricate, exceeding the internodes, green and usually with purplish-vinaceous spots on the adaxial side, densely lepidote abaxially, sparsely white-lepidote becoming denser towards the apex adaxially, smooth at anthesis; main axis smooth at anthesis, sulcate in sicco, green, glabrous, internodes 8.5-9.5 mm long; floral bracts broadly ovate, apex obtuse, 27-30 × 40-42 mm, shorter than sepals, green at anthesis, densely lepidote abaxially, adaxially glabrous, ecarinate, secund with the flowers before and during anthesis, coriaceous, thicker toward the base, smooth at anthesis, corrugate-sulcate in sicco. Flowers 56-60 mm long, night-blooming, with garlic scent and producing translucent mucilage, distichous, densely disposed, secund at anthesis; pedicel 9.5-11 mm long, 9-11 mm in diameter at distal end, stout, green, glabrous; sepals obovate, apex obtuse to rounded, (22-) 30-35 × (15-)21-23.5 mm, green, glabrous on adaxial side, densely lepidote abaxially, thick and coriaceous near the base, margins membranaceous; corolla 33-37 mm in diameter; petals obovate, apex rounded to emarginate, recurved near the apex at anthesis, 38-39 × 17-21 mm, greenish-white, strongly thickened with membranous margins, bearing 2 appendages at the base; appendages 9.5-11.6 × 3-3.8 mm, spathulate, basally adnate to the petals for 4.5-6.5 mm, apex irregularly acute-dentate; filaments free, complanate, 19-22 × 1.7-2 mm wide, white; anthers 8.5-9.5 mm long, dorsifixed near the base, base bilobed, apex obtuse, arranged in 2 groups of three on each lateral side of the corolla at anthesis; pistil equalling or exceeding the stamens; ovary superior, 5.6-7.4 mm long; ovules caudate; style 24.5-27 mm long, green; stigma tubo-laciniate type I, denticulate at the margins, 1.7-1.8 mm in diameter, green. Fruits a capsule, ellipsoid, apex apiculate, 32-45 mm long, 9.5-10.5 mm diameter, brown. Seeds fusiform, 3-4 mm long, brown; basal coma 15-21 mm long, beige; apical coma 1-1.6 mm, beige.

Distribution.

Stigmatodon lemeanus is endemic to Pedra dos Três Pontões, from the county of Afonso Cláudio in the central region of Espírito Santo, Brazil (Fig. 3 ), growing on bare and vertical walls of inselbergs, 1,000 m a.s.l. (Fig. 4 ). The Municipality of Afonso Cláudio recently created the Conservation Unit "Monumento Natural Municipal Pedra dos Três Pontões” to protect the local fauna and flora.

Habitat and ecology.

The plant is epilithic, heliophilic, living on bare and vertical rock walls of inselbergs, where it forms large populations (Figs 2A , 4C ), surrounded by Atlantic Forest fragments and farmland. In the type locality, Stigmatodon lemeanus grows on vertical rock walls (Fig. 2A-B ), including on the large and pointed peaks of the mountain, from which the name "Pedra dos Três Pontões” is derived (Fig. 4B ). In some places, they grow alongside sparse individuals of Pitcairnia diversifolia ( Bromeliaceae ), Mandevilla declinata ( Apocynaceae ), and the orchids Bulbophyllum weddellii Rchb.f., Bifrenaria harrisoniae (Hook.) Rchb.f., and Pseudolaelia dutrae Ruschi.

Phenology.

Flowers were recorded in October and fruits from May to October.

Etymology.

The specific epithet honours our friend Dr Elton Martinez Carvalho Leme (1960-), from Rio de Janeiro, Brazil, whose personal efforts have substantially contributed to the knowledge of the diversity, taxonomy, and systematics of Brazilian bromeliads. In addition, Dr Elton Leme is one of the authors of the genus Stigmatodon and has greatly contributed to the knowledge of these plants.

Preliminary IUCN conservation assessment.

Vulnerable: VU D2. The new species is known from only one very small population within a protected area, with an AOO of 4 km2. These figures fall within the limits for Critically Endangered (CR), based on criterion B2 (area of occupancy), taking into account only the number of locations or severely fragmented areas, which can lead to a continuous decline in the extent of occurrence, area of occupancy and quality of habitat of the new species. However, population isolation and fragmentation are natural conditions on inselbergs, thus evaluations of plant distribution on inselbergs probably yield overestimated values of AOO and EOO ( Leme et al. 2022). We do not have reliable information about this species’ continuing decline in plant numbers or extreme population fluctuations to enable us to apply criterion B. The Pedra dos Três Pontões inselberg is included in the Monumento Natural Municipal Pedra dos Três Pontões, an integral protection unit with the basic objective of preserving nature, with only the indirect use of its natural resources being permitted. Therefore, we estimate the human impact to be neither high nor continuous on the bare granitic and vertical walls of the inselbergs where it occurs. Due to the apparent rarity and very narrow distribution (a single location and AOO <20 km2), this species is prone to the effects of stochastic events in the near future, such as fire or impact from climbers. Therefore, it seems prudent to include it in the Vulnerable category: VU D2.

Additional material examined.

BRAZIL - Espírito Santo • Afonso Claudio , Pedra dos Três Pontões, inselberg, epilithic on vertical rock wall; 20°04 ’33” S, 41°02 ’39” W; 1078 m; 21 Oct. 2019; fr.; D.R. Couto & C.N. Fraga 4921; R • Afonso Cláudio, Pedra dos Três Pontões, rupícola no sol em paredão vertical; 18 May 2007; fr.; A.P. Fontana et al. 3386; MBML [MBML00029444] .

Notes.

Stigmatodon lemeanus is morphologically related to S. goniorachis , differing by the fewer number of leaves per rosette up to 20 (vs up to 30), acuminate-caudate leaf blade apex (vs acute apex), green, and usually with purplish-wine spots in the adaxial surface, usually vinaceous along margins (vs green); ovate peduncle bracts (vs elliptic); the main axis densely flowered at anthesis (vs laxly flowered), broadly ovate floral bracts (vs elliptic-ovate to suborbiculate) that are wider (40-43 mm vs 13-20 mm long); and the larger sepals (30-35 × 21-23.5 mm vs 21-30 × 15-19 mm), in addition to the characters cited in the diagnosis. Furthermore, while S. lemeanus is endemic to inselbergs in the mountainous region of Espírito Santo (> 1,000 m elevation), S. goniorachis is endemic to vertical walls of several coastal inselbergs by the sea, in the city of Rio de Janeiro, Brazil. When compared with S. attenuatoides D.R.Couto, Manhães & A.F.Costa ( Couto et al. 2020a: 144), another pachypetalous species endemic to the inselbergs in the south of Espírito Santo, S. lemeanus can be distinguished by the distinctly smaller size when flowering (50-67 cm vs 90-105 cm tall); the acuminate-caudate apex of leaf blades (vs acute or acuminate), which are smaller (17-20 × 2-2.8 cm vs 20-25(-36) × 3-5.5 cm), green, and usually with purplish-wine spots in the adaxial surface, usually vinaceous along the margins, without epicuticular wax (vs green concolorous, covered by a thick layer of white epicuticular wax); the simple inflorescence (vs compound) with fewer flowers (11-13 vs 20-40); the larger flowers (56-60 mm vs 50-55 mm long) with obovate sepals (vs elliptic), which are longer and wider (30-35 × 21-23.5 mm vs 22-24 × 16-17 mm), and with larger corolla (33-37 mm vs 27-28 mm in diameter).

Figures

Figure 1. Stigmatodon lemeanus. A. Habit. B. Leaf. C. Peduncle bract. D. Inflorescence before anthesis. E. Flower, frontal view with detail of the stamens arranged in two groups of three on each lateral side of the corolla. F. Flower, lateral view. G. Floral bract, adaxial side. H. Floral bract, abaxial side. I. Floral bract, detail of the thickest part at the base. J. Petal with two basal appendages. K. Basal appendages, details. L. Stamen. M. Pistil. From the holotype D. R. Couto & C. N. Fraga 4926 (MBML). Drawn by Joelcio Freitas.

Figure 2. Stigmatodon lemeanus. A - B. Plants in situ at the type locality. C. Flowering individual in cultivation. D. Lateral view of the flower and floral bract. E. Frontal view of the flower. F. Details of the tubo-laciniate stigma and anthers. Photographs: A, C-F by Dayvid R. Couto, B by Andre P. Fontana.

Figure 3. Geographic distribution of the 16 species of Stigmatodon on the inselbergs of Espirito Santo. A. S. amadoi, S. apparicianus, S. attenuatoides, S. belloi, S. bifidus. B. S. euclidianus, S. fontellanus, S. funebris, S. harrylutheri, S. magnibracteatus. C. S. multifoliatus, S. plurifolius, S. sanctateresensis, S. vellozicolus, S. viridibracteatus. D. S. lemeanus.

Figure 4. Stigmatodon lemeanus. A - B. General view of the landscape at the type locality, highlighting the large and vertical pointed peaks of Pedra dos Tres Pontoes. C. Detail of the population on a vertical rock wall alongside sparse individuals of Pitcairnia diversifolia; some individuals grow close to the base of the slope, which facilitated the collection of some specimens for the study and description of the new species. Photographs: A by Andre P. Fontana, B-C by Claudio N. Fraga.