Triumfetta decaglandulata J.M. Cardoso, A. Gil

Cardoso, Jesiane Miranda, Fernandes-Júnior, Aluísio José & Gil, André Dos Santos Bragança, 2022, Triumfetta decaglandulata (Grewioideae, Malvaceae), a new species from the Cerrado-Amazon ecotone, Northern Brazil, Phytotaxa 545 (3), pp. 287-293 : 288-292

Triumfetta decaglandulata J.M. Cardoso, A. Gil & A.J.Fernandes-Jr., sp. nov. ( Figures 1 and 2 )

Type:— BRAZIL. Pará: São Geraldo do Araguaia, Serra dos Martírios-Andorinhas, caminho para o morro do Passat , 6°17’33.6” S, 48°32’40.5” W, 24 May 2019, fl., fr., K.N.L. Alves, A.S.B. Gil, L. Schneider, C.S. Nunes, J.M. Cardoso, R. Batista-Silva, R. Nunes & N.P. Pinto-Silva 244 (holotype: MG; isotypes: IAN, RB) .

Diagnosis:— Similar to Triumfetta lappula , but it differs from it for having 6-celled ovary, glands on the androgynophore and lack of membranous urceolus. It differs from all other species of Triumfetta due to ten glands on androgynophore.

Shrubs ca. 2 m tall. Stems brownish, cylindrical, pubescent, with yellowish stellate trichomes of slender, long and thicker, shorter hairs. Leaves simple; stipules 3.1–5.2 × 0.9–1.1 mm, elliptic, ciliate, with simple and biradiated trichomes, apices acute; petioles 0.3–6 cm long, tomentose, with yellowish stellate trichomes; blades 1.2–9.2 × 0.4– 6.8 cm, entire to slightly 3-lobed, discolor, ovate (basal ones) to elliptic (upper ones), base cuneate with 3 basal teeth on each side with cupuliform glands, margins irregularly serrate, apices acuminate, adaxial surface pubescent, with slender biradiated and stellate trichomes over the surface and thicker stellate trichomes on the nerves, abaxial surface pubescent to tomentose, with slender and elongated stellate trichomes over the surface, and thicker and elongated stellate trichomes on the nerves. Inflorescence axillary, cymes 3-flowered; peduncles 1.4–2.2 mm long; bracts 2.4–3.5 × 0.7–1 mm, lanceolate, pubescent, with simple and biradiated trichomes densely toward the apex; pedicels 0.8–1.9 cm long, pubescent, with simple and stellate trichomes; bracteoles 1.2–1.6 × 0.1 mm, lanceolate to oblong, ciliate, with simple and biradiated trichomes. Flower pentamerous, hermaphroditic; floral bud oblong, 1.7–2.7 mm long; sepals 2.7–3.3 × 0.2–0.4 mm, oblong, pubescent, with biradiated and stellate trichomes, appendices ca. 0.1 mm long; petals absent; androgynophore 0.4–0.5 mm long, glands 10, orbicular; without membranaceous urceolus; stamens 10–12, free, filaments 1–2.4 mm long, glabrous, anthers bi-thecate; ovary ovoid, ca. 0.1 × 0.1 mm, 6-celled, style 2–2.4 mm long, glabrous, stigma 1, bifid. Fruits immature, 0.2 × 0.1 mm, globose, epicarp pubescent, with glandular trichomes, ca. 50 uncinate spines, hyaline, glabrous; seeds not seen.

Distribution and habitat:— This species is only known from its type-locality in São Geraldo do Araguaia County, Serra dos Martírios-Andorinhas, Pará State, Northern Brazil ( Fig. 3 ). Serra dos Martírios-Andorinhas is limited by two conservation units: Área de Proteção Ambiental de São Geraldo do Araguaia (APA Araguaia) and Parque Estadual da Serra dos Martírios-Andorinhas (PESAM) ( SECTAM 2006; Silva 2009; IDEFLOR-BIO 2019). The area is in the Cerrado -Amazon ecotone and hosts different habitats such as alluvial ombrophilous dense forest, campo cerrado, campo sujo and secondary vegetation ( SECTAM 2006). It is in the “arc of deforestation”, which is the region mostly threatened by deforestation in the Brazilian Amazon ( Silva 2009, IDEFLOR-BIO 2019). The new species grows on the roadside of a pasture, at elevation of ca. 170 m.

Conservation status:— The new species was found at APA Araguaia, in a pasture area, by the roadside. Despite being placed at a conservation unit, the area suffers intense anthropic stress, with agribusiness expansion. Only one sample of Triumfetta decaglandulata was collected and it was impossible to obtain information of its extent of occurrence (EOO) and area of occupancy (AOO). The genus Triumfetta is widely distributed in Brazil, and it is often present in open areas, but few specimens are represented in herbaria. Thus, this lack of distribution data frequently affects the conservation status assessment of the species. According to the IUCN Red List Categories and Criteria (2012), Triumfetta decaglandulata should be considered as Data Deficient (DD) because only the typespecimen is known and appropriate data on abundance and/or distribution are unknown. However, we emphasize that its natural habitat located at APA Araguaia is under anthropic impact, and therefore, attention should be redirected to the preservation of this unique known population.

Etymology:— The epithet “ decaglandulata ” refers to the ten glands observed in the species’ androgynophore.

Taxonomic affinities:— According to the classification by Lay (1950), T. decaglandulata fits the Triumfetta sect. Lappula DC. based on its rigid spines, as well as the series Uncinatae Sprague & Hutch. , based on its uncinate spines. The new species is mainly featured by the ten glands on the androgynophore and by the absence of membranaceous urceolus and petals ( Fig. 1F ).

Most of Triumfetta have pentamerous flowers and five glands on the androgynophore ( Lay 1950; Halford 1997), except for Triumfetta acahuizotlanensis González-Martínez, J. Jiménez Ram. & Rios-Carrasco (2016: 273) , which has tetramerous flowers and four glands ( Jiménez-Ramírez et al. 2016), as well as for T. lappula , which is the only species lacking glands ( Lay 1950). T. decaglandulata is the only known species belonging to genus Triumfetta that has ten glands on the androgynophore.

Triumfetta decaglandulata possess absent petals, character also shared with T. lappula and T. centralis Halford (1997: 543) . Triumfetta albida (Domin) Halford (1997: 562) and T. longipedunculata Halford (1997: 562) also have absent petals or, when present, often inconspicuous. Although the new species and T. lappula , are registered in the Americas, T. albida , T. centralis , and T. longipedunculata occur in Australia. Triumfetta albida differs from the new species by the presence of 30 or more stamens (vs. 10-12 stamens) and ovary 2-celled (vs. ovary 6-celled). Triumfetta centralis also differs by the ovary 2-celled (vs. ovary 6-celled), and the toothed stigma (vs. bifid stigma). Triumfetta longipedunculata differs by the presence of ca. 60 stamens (vs. 10-12 stamens) and 3-lobed stigma (vs. bifid stigma).

Triumfetta decaglandulata resembles T. lappula in stem indument and leaf shape, lack of petals and geographic distribution – both species are recorded in Pará State, Northern Brazil. However, it differs from T. lappula because it has 10-12 stamens (vs. 15 stamens), ovary 6-celled (vs. 2-celled), ten glands on the androgynophore (vs. androgynophore absent) and lack of membranaceous urceolus (vs. inconspicuous urceolus) (see Gual-Díaz & Pérez 2018).

Figures

FIGURE 1. Illustration of Triumfetta decaglandulata: A. Habit. B. Detail of the leaf base. C. Inflorescence. D. Flower. E. Sepals. F. Glands on the androgynophore and ovary. G. Cross section of the ovary (A-G based on K.N.L. Alves et al 244; Drawn by Alex Pinheiro).

FIGURE 2. Holotype of Triumfetta decaglandulata (K.N.L. Alves et al. 244 - MG).

FIGURE 3. Map of Triumfetta decaglandulata (red-dot) distribution in Serra dos Martírios-Andorinhas, Pará State, Brazil.