Stachytarpheta liviae P.H.Cardoso & Salimena, 2024

Cardoso, Pedro Henrique, Salimena, Fátima Regina Gonçalves, Dittrich, Vinícius Antonio De Oliveira, Neto, Luiz Menini & Trovó, Marcelo, 2024, Stachytarpheta liviae (Verbenaceae): a noteworthy new species from the Espinhaço Range, Brazil, Phytotaxa 633 (3), pp. 291-299 : 292-297

Stachytarpheta liviae P.H.Cardoso & Salimena sp. nov. ( Figs. 1 , 2 ).

Type:— BRAZIL. Bahia, Jacaraci, Morro do Chapéu, 25 April 2010, V. A. O. Dittrich & T. C. Novais 1695 (holotype CESJ-57707, isotype HUEFS-173856).

Diagnosis:— The new species is similar to Stachytarpheta lacunosa Martius ex Schauer (1847: 571) , but differs by its patent leaves, tuberculate on adaxial surface, crenulate at margins, linear bracts with acute apex, calyx with two sinuses, blue corolla with smaller lobes, the two upper lobes black on the throat, and fruit with acute apex. Additionally, it can be confused with S. tuberculata S. Atkins (2005: 195) due to its similar leaf morphology, but differs regarding reproductive characteristics.

Shrubs ca. 1.8 m tall, erect, densely branched, branches gnarled, enlarged at nodes, tetragonal, densely strigose, becoming glabrescent at maturity, with conspicuous leaf-scars. Leaves crowded at apex of stems, decussate, patent, petioles 0.6-0.8 cm long, strigose; leaf blade 1.5–2.5 × 0.8–1.8 cm, broadly ovate or subrotund, coriaceous, concolorous, with abundant and conspicuous sessile glands, apex rounded or emarginate, base cuneate, obtuse or rounded, margin crenulate, with blackish teeth in young leaves, ciliate, plane to revolute, adaxial surface tuberculate with white hairs on the protuberances, strigose, abaxial surface with prominent veins forming a reticulate network, foveolate, strigose along veins, foveolae round, tomentose. Spikes 2.5–3 × 1–1.2 cm, terminal, cylindrical, tightly packed, few-flowered, almost overtopped by surrounding leaves, obscuring bracts, calyces and part of the corollas, rachis not visible, slightly excavated, strigose, unelongated at fruiting; floral bracts 0.6–0.8 × 0.2 cm, linear, chartaceous, shorter than the calyx, green-purplish, apex acute, abaxial surface strigose, adaxial surface glabrous, margin ciliate, becoming leathery and brown after fruiting. Flowers sessile, spirally and densely arranged; calyx not embedded in the rachis excavations, a narrow tube from base to apex, ca. 1.2 × 0.3 cm, erect, purplish, externally strigose with pedicellate glandular hairs at the upper part of the tube, 4-toothed, teeth unequal, lateral, with two longer outer ones, acuminate, ca. 0.1 cm long, 2 sinuses, with ca. 0.4 cm long, sessile glands present apically, brown after fruiting; corolla blue, hypocrateriform, zygomorphic, tube 1.6–2 cm long, straight, well-exerted from the calyx, externally with pedicellate glandular hairs, internally with a ring of hairs just above the ovary, limb 5-lobed, lobes ca. 0.2 cm wide, with pedicellate glandular hairs, the two upper lobes black on the throat, throat densely strigose with white hairs that contrast with the black spots; androecium with 2 fertile stamens and 2 staminodes, inserted at the top of the corolla tube, included, stamens with divergent thecae, staminodes pilose; gynoecium reduced to a single functional carpel, 2-locular, 1 ovule per locule, ovary ca. 0.3 cm long, style filiform, 1.7–2.1 cm long, exserted, stigma capitate, green. Fruit ca. 0.4 cm long, narrow obloid, brown, apex acute, without stylopodium, with attachment scar, outer surface slightly striate, with a thin and flat commissure, commissural surface papillose, totally covered by the persistent calyx, splitting into two cluses when ripe.

Distribution and ecology:— Stachytarpheta liviae is currently known only from the type specimens (holotype and isotype), collected in the municipality of Jacaraci, specifically in an area known as Morro do Chapéu, which belongs to the northern Espinhaço region in Bahia state ( Fig. 3 ). Only a single population with 150–200 individuals was observed in the field, at 1,415 m a.s.l. (V.A.O. Dittrich, personal observation in 2010). This species grows in campos rupestres of the Caatinga domain in a transition zone with the Cerrado domain. In addition, it is not sympatric with any other Stachytarpheta species.

The micro-endemism is a striking feature of several Stachytarpheta species ( Atkins 2005; Cardoso & Salimena 2023). Thus, we believe that S. liviae is endemic to Morro do Chapéu. Further field expeditions are crucial to acquire more detailed information about its distribution and biology.

Phenology:— The type specimen was collected with flowers and fruits in April, but the coexistence of old, mature and young inflorescences in the same specimen suggest a continuous bloom. Further observations and new collections may provide more precise information about the species’ phenology.

Preliminary conservation assessment:— Morro do Chapéu, where Stachytarpheta liviae was collected, is an unprotected area and a touristic destination in the municipality of Jacaraci. The species has an AOO of less than 10 km 2, and unregulated tourism can represent a threat to its survival. However, due to the lack of distributional and ecological information that would enable us to understand potential declines, it is classified as (DD) Data Deficient ( IUCN 2012, 2022).

Etymology:— The specific epithet is dedicated to our dear friend, Dr. Lívia Echternacht, in honor of her significant contribution to Brazilian botany, especially concerning the flora of campos rupestres. Lívia is a professor at the Universidade Federal de Ouro Preto and has focused her research on Eriocaulaceae . She has already described a new species of this family for the municipality of Jacaraci, highlighting the imperative necessity of additional research on the local flora ( Echternacht 2014).

Discussion:— The specimen V.A.O. Dittrich & T.C. Novais 1695 was previously identified as Stachytarpheta tuberculata in herbarium collections. However, its resemblance with this species is limited to vegetative characteristics, such as the tetragonal, gnarled branches, leaves crowded at apex of stems, petiolate, coriaceous, tuberculate on adaxial surface, and with prominent veins forming a reticulate network on the abaxial surface. It differs from S. tuberculata in having spikes 2.5–3 × 1–1.2 cm, few-flowered, almost overtopped by surrounding leaves, obscuring bracts, calyces and part of the corollas, rachis not visible, linear floral bracts, calyx not embedded in the rachis excavations, ca. 1.2 cm long, blue corolla with two upper lobes black on the throat, and fruit with acute apex (vs. spikes 5–10 × 0.4–0.6 cm, densely flowered, not overtopped by surrounding leaves, ovate or ovate-triangular bracts, calyx embedded in the rachis excavations, 0.8‒1 cm long, entirely blue corolla, and fruit with rounded apex in S. tuberculata ).

A traditional diagnostic feature within Stachytarpheta corresponds to the morphology of the inflorescences, whether the calyx is embedded or not in the rachis excavations ( Walpers 1845; Schauer 1847; Atkins 2005). The specimen V.A.O. Dittrich & T.C. Novais 1695 and the species S. tuberculata differ in this characteristic; therefore, according to classical classifications, they are not close. On the other hand, the presence of tightly packed inflorescences, calyces 4-toothed and blue corollas allow it to be included in the informal group Commutata defined by Atkins (2005). However,its distinctive traits do not match the circumscriptions of any known species in this group ( S. discolor Chamisso (1832: 251) , S. cearensis Moldenke (1941: 54) , S. commutata Schauer (1847: 570) , S. lacunosa , S. hispida Nees & Martius (1823: 69) , S. mexiae Moldenke (1940: 472) , S. olearyana P.H. Cardoso (2022: 730) , S. sobraliana P.H.Cardoso, R.J.V.Alves & Salimena (2019: 287)) . Thus, we conclude that it is a distinct species.

Stachytarpheta liviae is more similar to S. lacunosa . Both species share petiolate leaves, broadly ovate or subrotund leaf blades, strigose adaxial surface, abaxial surface with prominent veins forming a reticulate network, with round and tomentose foveolae, inflorescences with rachis not visible, and calyx not immersed in the rachis excavations. From S. lacunosa , S. liviae differs in having patent leaves, tuberculate on adaxial surface, crenulate at margins, linear bracts with acute apex, calyx with 2 sinuses, blue corolla with lobes ca. 0.2 cm wide, the two upper lobes black on the throat, and fruit with acute apex (vs. erect leaves, smooth on adaxial surface, margin entire near the base becoming conspicuously serrate towards the apex, narrowly triangular or triangular bracts with acuminate or caudate apex, calyx with one adaxial sinus, lilac or rarely blue-purplish corolla with lobes ca. 0.5 cm wide, pale lilac to almost white in the throat, and fruit with obtuse apex in S. lacunosa ). In addition, both species have a distinct distribution, being S. lacunosa endemic to Chapada Diamantina ( Atkins 2005, Fig. 3 ).

Microendemism is a common feature in Stachytarpheta and, similarly to S. liviae , other species are known solely from the type specimen or by a few collection records ( Atkins 2005, Cardoso et al. 2023a,b). Therefore, even though S. liviae is known exclusively from the type specimens, its recognition plays a crucial role in addressing knowledge gaps in the flora of the northern Espinhaço, especially in the Jacaraci municipality. Another species of Verbenaceae , Lantana speciosa Salimena & T.R.S. Silva (2017: 126) , has its type specimen collected in Morro do Chapéu as does S. liviae ( Silva et al. 2017) .Additionally, a species of cactus, Arrojadoa olsthoorniana Hofacker, M.Machado & R.Pontes (2021: 3026) , was also recently described from Jacaraci ( Hofacker et al. 2021). These discoveries support Echternacht (2014) perspective on the flora of the region.

In the Espinhaço Range as a whole, various forms of anthropogenic pressures, such as the expansion of agribusiness, urbanization, increased uncontrolled wildfires, and mining, have been devastating large portions of natural habitats. Consequently, many endemic plant species have their populations increasingly confined to reduced and remote areas ( Martinelli & Moraes 2013; Fernandes et al. 2020). Thus, the discovery of new species in this region also serves to emphasize the necessity for biodiversity conservation policies.

Figures

FIGURE 1. Stachytarpheta liviae. A: Habit, the arrows showing the post-flowering inflorescences with leathery and brown bracts and calyces after fruiting. B: Branch with leaves and inflorescence, the arrows showing the sessile glands in the leaf blade. C: Inflorescence, almost overtopped by surrounding leaves, showing corolla throat and stigma. D: Corollas, the arrows showing the pedicellate glandular hairs. (V.A.O. Dittrich & T.C. Novais 1695).

FIGURE 2. Stachytarpheta liviae, herborized specimen.A: Leaf blade, adaxial surface.B: Leaf blade, abaxial surface.C,D: Inflorescence, showing bracts, calyces and corolla. (V.A.O. Dittrich & T.C. Novais 1695, CESJ).

FIGURE 3. Map showing the distribution of Stachytarpheta liviae and two morphologically similar species. BA: Bahia state; MG: Minas Gerais state.