Stigmatodon viridibracteatus D.R. Couto, Fraga & Leme, 2022

Leme, Elton M. C., Couto, Dayvid R., Kollmann, Ludovic J. C. & Fraga, Claudio Nicoletti De, 2022, Novelties in Stigmatodon (Bromeliaceae, Tillandsioideae), a genus endemic to Brazil: three new species, one new combination, and two new stigma types, Phytotaxa 576 (3), pp. 233-249 : 243-245

Stigmatodon viridibracteatus D.R. Couto, Fraga & Leme , sp. nov. ( Figs. 6 A–G )

Diagnosis: ___ This new species differs from S. euclidianus , its closest morphological relative, by the smaller size when in bloom (55–62 cm vs. 60–80 cm tall), leaf blades smaller (19–23.5 × 3–4 cm vs. 25–33 × 5–6 cm), and by suborbicular floral bracts (vs. broadly ovate), with obtuse apex (vs. acuminate to acute), shorter and broader (24.5–29 × 36–40 mm vs. 30–35 × 25–30 mm), smooth to inconspicuously corrugate-sulcate near the apex at anthesis (vs. strongly corrugate-sulcate at anthesis), green at anthesis (vs. greenish toward the base only before anthesis, stramineous toward the apex).

Type: — BRAZIL. Espírito Santo: Barra de S „o Francisco , inselberg between Vila Paulista and Santa Teresinha, epilithic on vertical rock wall, forming a large population, 250 m elevation, 18° 35’ 35” S, 40° 48’ 16” W, 17 October 2019, D. R. Couto 4829, P. M. Gonela , T. Condez & C. N. Fraga (holotype MBML!) .

Description:— Plants rupicolous, flowering 55–62 cm tall. Leaves 20–25 in number, rosulate, thick coriaceous, forming a funnelform rosette; sheath elliptic, 10–13 × 7–8.5 cm, densely and minutely castaneous lepidote on both sides; blade narrowly triangular, apex acuminate-caudate, recurved, canaliculate toward the base, flat toward the apex, suberect, 19–23.5 cm long, 3–4 cm wide at the base, completely covered on both sides with a dense layer of whitecinereous trichomes obscuring the color of the blades, margins truncate, 1–1.5 mm thick. Peduncle arching, 40–45 cm long, 0.6–0.7 cm in diameter, green, glabrous, smooth at anthesis, sulcate when dry; peduncle bracts the basal ones subfoliaceous, the upper ones ovate, apex acute and apiculate, 2.5–4 × 2.5–2.7 cm, erect, almost completely hiding the peduncle, distinctly exceeding the internodes, densely and coarsely white lepidote toward the apex, green near the base and cinereous toward the apex, strongly sulcate at anthesis. Inflorescence simple, suberect, 13–14 cm long, apex obtuse at anthesis, 9–18 flowered; main axis smooth at anthesis, sulcate when dry, green, glabrous, internodes 8–9 × 5–7 mm; floral bracts suborbicular, apex obtuse, 24.5–29 × 36–40 mm, distinctly shorter than the sepals, densely and inconspicuously white lepidote adaxially, sparsely and inconspicuously white lepidote to glabrous abaxially except the apex being sometimes subdensely white lepidote, ecarinate but bearing a broadly obtuse keel near the apex, slightly secund with the flowers at anthesis, coriaceous, smooth to inconspicuously corrugate-sulcate near the apex at anthesis, distinctly corrugate-sulcate when dry, green. Flowers 45–50 mm long, nocturnal, with a fruit-like fragrance and producing translucent mucilage, distichous, subdensely disposed and distinctly secund at anthesis; pedicel 6.5–8 mm long, 8–9.6 mm in diameter at the distal end, stout, green, glabrous; sepals elliptic, apex obtuse, 25–30 × 17–20 mm, green, glabrous abaxially, densely and inconspicuously lepidote adaxially, thick and coriaceous near the base, margins membranaceous; petals obovate, rounded and apex emarginate, recurved near the apex at anthesis, 34–36 × 14–20 mm, greenish-white, thicker toward the base, bearing 2 appendages at the base; appendages 9–11 × 3–4 mm, spathulate, basally adnate to the petals for 3.5–6.5 mm, apex irregularly dentate to acute; corolla campanulate, 25–30 mm in diameter; filaments free, complanate, 16.5–22.5 × 1.3–2.2 mm, white; anthers 7–8.5 mm long, dorsifixed near the base, base bilobed, apex obtuse, arranged three on each lateral side of the corolla at anthesis; stigma tubo-laciniate type I, margins denticulate, 1.5–2 mm in diameter, greenish; ovules caudate. Capsules unknown.

Etymology: ___ The name of this new species is a reference to the green color of its floral bracts, which distinguishes it from other cinereous-leafed species of Stigmatodon .

Additional specimen examined (paratypes): ___ BRAZIL. Espírito Santo: Barra de S „ o Francisco , inselberg between Vila Paulista and Santa Teresinha, epilithic on vertical rock wall, forming large population, 250 m elevation, 18° 35’ 35” S, 40° 48’ 16” W, 17 October 2019, D. R . Couto 4826, P. M. Gonela , T. Condez & C. N . Fraga ( R!); ibidem, D. R. Couto 4831, P. M. Gonela , T. Condez & C. N. Fraga ( RB!) .

Distribution and habitat:— Stigmatodon viridibracteatus is epilithic, found on vertical granitic slopes of inselbergs located in the county of Barra de S„o Francisco, Espírito Santo state, near the border with Minas Gerais. At the type locality, these plants grow on the north face of the cliff, where they form large and dense populations, along with sparse individuals of Encholirium horridum Smith (1940: 32) and the Cactaceae Coleocephalocereus fluminensis (Miquel) Backeberg (1941: 53) .

Preliminary conservation status: ___ Vulnerable [VU: D2 ]. Stigmatodon viridibracteatus is only known from its type locality, a lowland inselberg in the Atlantic Forest from northwest of Espírito Santo. It has an AOO of 4 km 2, an undefined EOO, and is not found in any conservation unit. Its small population is unprotected and prone to the effects of stochastic events in the near future. Thus, it seems prudent to include this new species in the Vulnerable category [VU: D2 ]. However , further field survey may change the conservation status of S. viridibracteatus , since there is an important sampling gap in the northwestern region of Espírito Santo, mainly comprising the locally abundant but difficult-to-access inselbergs.

Observations: ___ Stigmatodon viridibracteatus is morphologically closely related to S. euclidianus ( Leme & Brown, 2010: 57) Leme, G.K. Brown & Barfuss ( Barfuss et al. 2016: 57), but differs from it mainly by the smaller size when in bloom (55–62 cm vs. 60–80 cm tall), inflorescence shorter (13–14 cm vs. 20–25 cm long), and by the suborbicular floral bracts (vs. broadly ovate), apex obtuse (vs. acuminate to acute), shorter and broader (24.5–29 × 36–40 mm vs. 30–35 × 25–30 mm), smooth to inconspicuously corrugate-sulcate near the apex at anthesis (vs. strongly corrugate-sulcate at anthesis), green (vs. greenish toward the base only before anthesis, lightly castaneous-stramineous toward the apex at anthesis).

On the other hand, it can be also confused with S. magnibracteaus ( Leme & Kollmann, 2014: 94) Leme, G.K. Brown & Barfuss ( Barfuss et al. 2016: 57), but can be distinguished by its higher number of leaves (20–25 vs. ca. 18 in number), longer peduncle (40–45 cm vs. 20–32 cm), with ovate peduncle bracts and attenuate then apiculate apex (vs. ovate-lanceolate, and acuminate to caudate apex), floral bracts shorter (24.5–29 mm vs. 34–47 mm long), distinctly shorter than the sepals (vs. equaling to exceeding the sepals), broadly ovate with obtuse apex (vs. ovate, acute apex), smooth at anthesis (vs. strongly corrugate-sulcate at anthesis), and green (vs. dark reddish-castaneous near the base mainly at the beginning of the anthesis to stramineous toward the apex), flowers with a fruit-like fragrance and producing translucent mucilage (vs. with a garlic odor and without any mucilage), sepals broader (17–20 mm vs. 12–15 mm wide), green (vs. yellowish-green), smaller petals (34–36 × 14–20 mm vs. ca. 40 × 22 mm), and shorter filaments (16.5–22.5 mm vs. 27 mm long).

Figures

FIGURE 6. Stigmatodon viridibracteatus. A. General view of the inselberg landscape at the type locality. B. Population on vertical rock wall at the type locality. C–D. Habit. E. Lateral view of the flower. F. Frontal view of the flower. G. Details of the tubo-laciniate stigma (photos by D.R. Couto).