Stachytarpheta flavovirescens P. H. Cardoso 2021, sp. nov.

Stachytarpheta flavovirescens P.H.Cardoso sp. nov. (Fig. 1 A–I, Fig. 2A–D).

Type:— BRAZIL. Goiás, Alto Paraíso de Goiás, estrada vicinal para Bona Espero, próximo à rodovia Alto Paraíso de Goiás, 17,1 km do trevo sul de Alto Paraíso de Goiás em direção à São Jorge, 14°04’43.5” S, 47”37’50.5” W, 4 September 2013, J. R . Pirani et al. 6431 (holotype SPF 207740!).

Diagnosis: —The new species is similar to Stachytarpheta mollis Moldenke (1947: 370), but differs by the petiolate leaves (vs. sessile leaves), ovate to rotund leaf blade (vs. elliptic leaf blade), with smaller leaves in the same axil (vs. without smaller leaves in the same axil), bracts 0.6–0.8 cm long (vs. bracts 0.9–1.2 cm long), oval-triangular (vs. narrowly triangular), with puberulous abaxial surface and trichomes concentrated at the base (vs. entirely villous).

Shrubs 0.5–2 m tall, profusely branched, branches erect, woody, smooth, rounded, villous when young, puberulous when adult. Leaves spreading, opposite, slightly discolorous, petiole 0.5–1 cm long, leaf blade 1.6–3.9 × 1.4–2.5 cm, with smaller leaves in the same axil, ovate to rotund, subcoriaceous, apex obtuse to rounded, base cuneate, decurrent into the petiole, margin entire near the base, crenate-serrate towards the apex, not revolute, adaxial surface sericeous, abaxial surface sericeous-canescent, more numerous white hairs near the petiole, veins prominent. Inflorescences 2–10 × 1.2–2 cm, terminal, cylindric, congested, rachis not visible, becoming elongate in fruiting. Flowers sessile, spirally arranged; floral bract 0.6–0.8 cm long, appressed against the calyx, herbaceous, yellow-greenish, oval-triangular, apex acuminate to caudate, abaxial surface puberulous with trichomes concentrated in the base, margin ciliate; calyx (1–) 1.2–1.4 cm long, herbaceous, yellow-greenish, flattened-cylindrical, 5-toothed, teeth conspicuously acute, externally sparsely sericeous-strigose, erect, not embedded in excavations in the rachis; corolla 1.4–2 cm long, a narrow tube and spreading lobes, atropurpureous to black, externally with glandular-pedicellate trichomes, throat entirely pubescent, with a dense ring of hairs just above the ovary; androecium included, stamens 2, thecae divergent, staminodes 2, inserted at the top of the corolla tube; ovary ca. 2 mm long, narrow oblong, style 1.4–2.2 cm long, filiform, stigma capitate. Fruit a schizocarp 3.4–5.5 mm long, brown, outer surface reticulate, with thin and flat commissure, apex rounded, with prominent attachment scar, with short stylopodium, covered by the persistent calyx, separating into two cluses.

Paratypes:— BRAZIL: Goiás. Alto Paraíso de Goiás, Parque Nacional da Chapada dos Veadeiros, trilha para as Corredeiras, 24 January 2005, J . Paula-Souza et al. 4565.0 (ESA!); Alto Paraíso de Goiás, Rio das Cobras, rod. para Colinas do Sul, 14 June 1993, G . Hatschbach & E. Barbosa 59512 (ESA!, K!, MBM!, MO).

Distribution— Stachytarpheta flavovirescens occurs in the Chapada dos Veadeiros region, in the municipality of Alto Paraíso de Goiás, in the Brazilian state of Goiás (Fig. 3). The species grows in campo rupestre and grasslands.

Phenology— This species was collected with flowers and fruits in January, June, and September.

Provisional conservation assessment— Although the Chapada dos Veadeiros is intensively studied, only three specimens of Stachytarpheta flavovirescens were collected to date in 1993, 2005, and 2013. It seems that the populations are small and narrowly distributed. This species is only known from three localities, and shows an EOO of 5.051 km 2 and an AOO of 12 km 2. Even though this species occurs within a protected area (i.e., Parque Nacional da Chapada dos Veadeiros), it is under multiple threats, including tourism, the expansion of agricultural and livestock activities, increased frequency of anthropogenic fires, and invasive exotic species, especially grasses (Fiedler et al. 2006, Souza & Felfili 2006, Barbosa 2008, Silva 2018). These threats have contributed to a decline of the species EOO, AOO, and habitat quality. Based on the criterion and sub-criteria B1ab (i, ii, iii) of the IUCN (2019), this species is provisionally considered as “CR” (Critically Endangered).

Etymology:— The specific epithet refers to the yellow-greenish inflorescences.

Taxonomic notes:— Among the Stachytarpheta species with atropurpureous to black corollas, S. flavovirescens is most similar to S. mollis, which is also endemic to the Chapada dos Veadeiros (Cardoso et al. 2020). Both species show hairy leaves, hairy bracts, hairy calyces, and congested, yellow-greenish inflorescences. However, they can be distinguished by the characters summarized in Table 1.

Stachytarpheta flavovirescens can also be confused with S. longispicata var. longipedicellata (Pohl) S. Atkins (2005: 230) when fruiting due to the elongated inflorescences. Both species are found in the region of the Chapada dos Veadeiros (Atkins 2005), but can be separated by a series of morphological features. Namely, S. longispicata var. longipedicellata has pedicellate flowers laxly arranged along the rachis and salmon-colored corollas, while S. flavovirescens has sessile flowers in a congested arrangement along the rachis, and atropurpureous to black corollas.

Table 1. Morphological comparison of Stachytarpheta flavovirescens, S. salimenae, S. glazioviana, S. mollis, and S. sericea.