Lobelia capixaba Rollim & Trovó, 2024

Rollim, Isis De Mello & Trovó, Marcelo, 2024, Lobelia capixaba, a new microendemic species of L. sect. Rhynchopetalum (Campanulaceae) from Espírito Santo, Brazil, Phytotaxa 668 (3), pp. 286-292 : 288-290

Lobelia capixaba Rollim & Trovó , sp. nov. ( Fig. 1 )

The new species is distinguished especially by its unilabiate corolla, with all lobes free at the apex. The lateral lobes are the longest among South American species, exceeding 3 cm in length, and are uniquely convolute. The morphologically closest species is Lobelia organensis , from which it differs by its glabrous leaves on both surfaces and the unilabiate corolla shape. It is also set apart from other unilabiate species, L. exaltata and L. hassleri , by a larger size of its corolla, which surpasses 3 cm in length, with all lobes free at the apex.

Type: — BRAZIL. Espírito Santo: Castelo, “estrada de Pedra Azul para o Parque Estadual do Forno Grande” 20º30’24.6” S, 41º04’53.1” W, 18 August 2023, I. M. Rollim & L. E. F. Silva 92 (holotype: R!).

Paratypes: — BRAZIL. Espírito Santo: Castelo , “Parque estadual do Forno Grande. Trilha para as piscinas. Floresta Ombrófila Densa Altomontana com inselbergues,” 20°30’58” S, 41°05’1” W, 12 February 2008, C. N. Fraga et al. 1823 ( MBML, NY, RB!, UPCB) ; 20°31’10” S, 41°05’15” W, 17 July 2008, C. N. Fraga et al. 2118 ( MBML, RB!, UPCB) .

Robust herbs, 3–4 m tall. Stem fistulous, erect or decumbent, striate, glabrous. Latex white. Leaves alternate, rosulate at the basis, sessile; blade 49.5–51 cm long, 7.2–8.7 cm wide, narrowly oblong or lanceolate, apex acute or acuminate, base narrowly decurrent, margin undulate, entire near base and minutely denticulate along leaf toward apex, hardened brown teeth, chartaceous when dry, discolor, glabrous on both surfaces, secondary veins 28–55 pairs forming an angle of 30º–45º with the midrib. Terminal raceme, congest, with smaller secondary basal racemes, 10–18 cm long, glabrous main axis; bracts inconspicuous, covered by flowers and pedicels, deflexed, linear, 20–26 mm long, 1–1.3 mm wide, apex acute, base decurrent, margin entire and ciliate, glabrous on both surfaces. Pedicel sigmoidal, 21–27 mm long, glabrous, without bracteoles; hypanthium globose; calyx lobes erect, triangular sepals, 14–23 mm long, 2–4 mm wide ate the base, margin entire, glabrous; corolla unilabiate with connate petals, in shades of white, greenish or pinkish, 3.5–4.5 cm long, tube straight, 0.8–1.5 cm long, lobes all similar morphologically in shape and size, free at the apex, pair of lateral lobes 3–3.7 cm long, trifid ventral lobes 2.5–3 cm long, convolute; stamens with filaments connate in a tube ca. 3 cm long, pubescent, anthers grayish, three dorsal 10–12 mm long, two ventral 8–10 mm long, the ventral pair with tufts of filiform hairs at apex; style glabrous, stigma 2-lobed, pubescent at apex. Capsule loculicide, globose, brown, 7–9 mm long, 4.5–5.7 mm wide, glabrous, about 2/3 adnate to hypanthium. Seed lenticular, suborbicular, asymmetrical, broadly winged, wing rigid, light brown, 0.8–1 mm long, 1–1.3 mm wide, testa finely striate.

Etymology: —The epithet “ capixaba ” is a reference to the restricted distribution of this species, endemic to Espírito Santo state. Capixaba is the name of the inhabitants born in this Brazilian state.

Distribution, Habitat and Conservation: — Lobelia capixaba is endemic to the state of Espírito Santo ( Fig. 2 ), know only from a few locations in the Forno Grande State Park, a protected area in the highlands of the southern part of the state, within the Atlantic Forest domain. The populations were found growing over granitic outcrops among patches of high montane forest intermixed with herbaceous and shrubby vegetation. Some individuals were observed near the boundaries of the Forno Grande State Park, including access roads and anthropized areas. Although most populations are located within a conservation unit, the region has been facing current conservational challenges. The edges of the conservation unit have a few fragments of native vegetation surrounded by crops and reforestation with exotic species ( Meirelles et al. 2012). In addition, the region is subject to the impact of intense rock mining activity ( Meirelles et al. 2012), representing a serious threat to the species and its natural habitat. Thus, L. capixaba should be considered Critically Endangered based on IUCN (2001) criteria B2a and D, since it is known only from a few populations, in a restricted area. In addition, it has a narrow distribution (EOO = 1.133 km 2), know from few localities and a low Area of Occupancy (AOO = 8.000 km 2).

Additional specimens examined: — BRAZIL. Espírito Santo, Castelo. Parque Estadual do Forno Grande , 10 June 2004, L. Kollmann et al. 6694 ( MBML) ; 10 June 2004, L. Kollmann et al. 6700 ( MBML) ; Estrada Pedra Azul para o Parque Estadual do Forno Grande , 18 August 2023, I. M. Rollim & L. E. F. Silva 93 ( R) .

Comments: —The new species belongs to Lobelia sect. Rhynchopetalum due to its robust habit, sessile leaves, large unilabiate flowers arranged in a terminal raceme, and lenticular winged seeds. The seed testa aligns with the description of Type C in Murata’s (1995) classification, characterized by highly elongated cells with less prominent cell walls, often described as having a striate-reticulate appearance. Lobelia capixaba is distinct from other species primarily due to its unique corolla, with the longest lobes among the South American species of the section, and also the only ones that are convolute. The color of flowers is also remarkable, being either as a whole single color or composed of a gradient of tones ranging from whitish or greenish to pink shades.

Lobelia capixaba is morphologically more related to L. organensis Gardner (1845: 128) . Besides the unique features cited, the new species is easily differentiated by its glabrous leaves (vs. pubescent leaves on the abaxial surface), its unilabiate corolla (vs. sub-bilabiate corolla), and its seeds with a rigid wing (vs. membranaceous wing). It shares similarities with L. exaltata Pohl (1831: 101) and L. hassleri Zahlbruckner (1907: 445) due to its unilabiate corolla, but can be distinguished by its larger corolla size, which exceeds 3 cm in length (vs. less than 2.8 cm long), and by having all lobes free at the apex (vs. all lobes connate at the apex).

In the state of Espírito Santo, the new species is sympatric with L. fistulosa Vellozo (1831: 157) and L. thapsoidea Schott ex Pohl (1831: 102) . It can be primarily differentiated from the first by its inconspicuous, deflexed, linear bracts (vs. conspicuous, erect, lanceolate bracts, often covering the pedicels), and its unilabiate corolla (vs. sub-bilabiate corolla). It is easily distinguished from L. thapsoidea by its glabrous leaves (vs. leaves tomentose on both surfaces), unilabiate corolla (vs. sub-bilabiate corolla), and broadly winged seeds (vs. short-winged seeds).

Figures

FIGURE 1. Lobelia capixaba Rollim & Trovó.A. Overview of the occurrence area and habitat. B. Fertile individual. C. Sterile individual. D. Fistulous stem detail. E. Margin leaf detail. F. Leaf detail. G. Terminal raceme with smaller secondary basal racemes. H. Inflorescence detail. I. Bracts detail. J−K. Gradient tones of the flowers. L−M. Lateral view of a flower, corolla with lobes strongly recurved. N. Fruit detail. O. Seeds detail. P. Seeds SEM analysis. Q. External seed coat detail. Photos A−J, N: Isis Rollim; K−M: Renato Goldenberg; O: Lucas Espindola; P−Q: Jean Pierre.

FIGURE 2. Distribution map of Lobelia capixaba Rollim & Trovó.