Harpochilus corrugatus Zappi & F.A. Silva, 2022

Silva, Fabio Araújo, Albuquerque-Lima, Sinzinando, Taylor, Nigel P. & Zappi, Daniela C., 2022, Harpochilus corrugatus (Acanthaceae), a new and endangered chiropterophylous species from the highlands of central-southern Bahia, Brazil, Phytotaxa 545 (2), pp. 151-162 : 152-153

Harpochilus corrugatus Zappi & F.A. Silva sp. nov.

Type:— BRAZIL, Bahia: Mun. Caetité, 1, 5 km ao sul de Brejinho das Ametistas, 900 m, 14º 9’ 0” S, 42º 28’ 60” W, 11 April 1980, R. M. Harley, G. Bromley, A. M. Carvalho, J. L. Hage & H. S. Brito 21212, fl., fr. (holotype: RB00035784 !; isotypes: CEPEC00025754 , IPA 49664, K001046211 image!, MO1404739 image!, NY000484263 image!, SPF!, UEC 39262 image!, US2950612 image!) .

Diagnosis:—The new species is closely related to Harpochilus neesianus , but differs by its sessile or nearly sessile distal leaves (not petiolated with geniculated petiole), blades deltoid, sometimes clasping the stem, strongly corrugated (not ovate-lanceolate, flat), calyx-lobes lanceolate (not triangular), corolla yellow, purple-brown tinged (not green throughout).

Description:—Scandent, poorly branched shrub to 3.5 m tall, all parts more or less shortly sericeous and velvety to the touch, eglandular trichomes articulate, glandular trichomes inconspicuous and less numerous than eglandular (except from the corolla), stems cylindrical, fistulose, 4–7 mm diam., densely sericeous, hairs turned distally. Leaves sessile, sometimes semi-amplexicaul, seldom petiolated in the lower branches, blades 3–6(–9) × 1.5–3(–4.6) cm, narrowly deltoid, strongly corrugated, grey-green (living specimens), slightly shiny and sericeous above, matt and strongly sericeous below, chartaceous, cystoliths inconspicuous, with 6–12 pairs of arcuate, brochidodromous veins, sunken adaxially, raised abaxially. Inflorescences in axillary dichasia, flowers paired, opposite or alternate; peduncle 1.0– 1.8 cm long, sericeous; pedicel 3–7.6 mm long, sericeous. Bracts 2, inconspicuous, 1–7 × 1–2.3 mm, narrowly triangular, sericeous, rhachila absent or to 10 mm long; bracteoles to 1.3 mm long. Calyx 5-lobed, lobes equal, erect, 12–17 × 2.6–3.8 mm, lanceolate, adaxially sparsely strigose, abaxially strigose, wide at base and forming a sinus at anthesis, apex acute, 1–3 veined, pale green. Flower-buds strongly curved. Corolla pale-yellow, with purple tinge towards the base, deeply bilabiate, internally glabrous to sparsely puberulous, externally puberulous with glandular and eglandular trichomes, upper lip 6.5–8.5 cm × 2.5–2.6 mm, and with wavy margins partly enclosing the filaments and style, bilobed at apex, the lobes c. 0.6 × 0.6 mm, the lower lip 2.2–2.5 cm long, 3-lobed, lobes pendent and curled up at anthesis, 6–7.6 cm long, 3–5.1 mm wide near the apex. Stamens 2, filaments 7.5–8.7 cm long, pubescent, connected to the upper third of the tube, exserted portion 22–25 mm long, anthers 6.4–8.1 × 3.1–3.2 mm, thecae 2, parallel, subequal; Pollen grains isopolar, with radial symmetry, 3-colporate, surface reticulated, endoaperture lalongate, a single row of areoles on a microreticulate tectum flanking the colporus, with a bireticulate continuum band in the mesocolpus area. Nectar-disk olive-green, and brown in fruit (living specimens), ring-shaped, fleshy, 4.4–5.3 mm diam. Ovary green (living specimens), 3.7–4 × 2–2.6 mm, ovoid, glabrous; style 10–10.5 cm long, distally pubescent, proximally glabrescent, exserted portion cream, turning purplish (living specimens), 3.0– 3.5 cm long, stigma punctiform. Capsules stipitate, ovate, acute at apex, glabrous, rugose (in dry specimens) without, basal portion 9–12 × 4 mm, apical portion 14–15 × 7–9 mm, turning pale brown when ripe and releasing 4 flattened, suborbicular, notched seeds 7–7.6 mm diam., thicker at the margin, testa pale brown.

Distribution and Habitat:—The distribution of H. corrugatus is associated with the Serra do Espinhaço that divides Minas Gerais and Bahia and turns north in the region of Licínio de Almeida continuing until Ibotirama (as the Serra da Garapa and Serra do Poção). The populations are discontinuous, and there is a single outlier population where the Serra do Espinhaço comes closer to the Serra das Almas, at the base of the Estrada Real, linking Livramento de Nossa Senhora to the town of Rio de Contas. It grows on rocky slopes of shrubby caatinga and campo rupestre on quartzitic/sandstone rock crevices in full sun, ranging from 650 to 980 m a.s.l. ( Fig. 4 ).

Conservation Status:—So far, the extent of occurrence (EOO) of the species is 7,501,601 km 2, while the area of occupancy (AOO) is only 36,000 km 2. It is difficult to estimate how discontinuous the species distribution really is, though we know that it occurs only on slopes, associated with rocks and shrubby caatinga and in the ecotone with campo rupestre, and it does not grow in the lowlands between the mountain ranges. Throughout its distribution we find habitat destruction by mining (around Brejinho das Ametistas, Caetité, Bahia), increasing amount of land being taken over for tropical fruit culture (nearby Livramento de Nossa Senhora, Bahia), and degradation by cattle-farming and increased risk of local fires throughout its range. The existing evidence places this species as Endangered (EN – B2 a,b(ii)) according to the IUCN (2014) guidelines.

Phenology and Ecology:—Flowering from September to May, fruiting from March to May. Harpochilus corrugatus has floral attributes associated with bat pollination ( Fig. 2 A–C ). These are styliflory, as the plants present their inflorescences and flowers on long branches above the vegetation ( Diniz et al. 2019) and semi-nocturnal flowers that last a single night, their anthesis starting after midday. The nectar is secreted and stored at the base of the tube with an average of 30 µl and a concentration of 21.5%. During a few hours of observation, a nectarivore Glossophaginae bat visited the flowers of H. corrugatus ( Fig. 5 ) confirming the predictions of chiropterophily for the species.

Etymology:—The specific epithet refers to the corrugated leaf as seen with the naked eye on both young and mature leaves.

Additional specimens examined (paratypes):— Bahia, Mun. Boquira, Torre da TELEBAHIA , 22 October 1993, G. Hatschbach et al. 65990, fl. ( CEPEC, MBM, US) ; same locality, Serra Geral, Serra do Brejo Grande , 11 March 1998, G. Hatschbach et al. 67634, fl. ( MBM) ; same locality, caminho para a Torre de Comunicações , 5 March 2021, 950m, D.C. Zappi et al. 5117, fl., fr. ( UB, UFPE) ; Mun. Caetité, Brejinho das Ametistas , 18 September 1978, A.M. Carvalho et al. 1777, fl. ( CEPEC, HUEFS, US) ; same locality, 26 July 1989, D.C. Zappi 172, fl., fr. ( SPF) ; same locality, 1 January 1991, N.P. Taylor et al. 1533, fl. ( CEPEC, K, SPF) ; same locality, 11/02/1997, M.L.S. Guedes et al. in PCD 5441, fl. ( ALCB, CEPEC, HUEFS, RB) ; same locality, 13 March 2002, N. Roque et al. 634, fl. ( SPF) ; same locality, 14 April 2002, F. França et al. 3744, fl., fr. ( HUEFS, UB, UEL, UFRPE) ; same locality, 10 January 2008, A.L. Côrtes et al. 66, fl. ( HUEFS) ; same locality, 851 m, 1 March 2017, G.M. Antar et al. 1392, fl., fr. ( CEN, SPF) ; same locality, 11 March 2021, D.C. Zappi et al. 5133, fl., fr. ( UB, UFPE) ; Mun. Caetité, Santa Luzia , c. 16 km da cidade, 10 May 1994, V.C. Souza et al. 5413, fl., fr. ( ESA, MBM, UFRN) ; Mun. Licínio de Almeida, 11 March 2021, D.C. Zappi et al. 5134, fl., fr. ( UB, UFPE) ; Mun. Livramento de Nossa Senhora/ Rio de Contas, no início da Estrada Real, 5 March 2021, D.C. Zappi & S. Albuquerque-Lima 5115, fl., fr. ( UB, UFPE) ; Mun. Rio de Contas, Trilha da Estrada Real , 2 January 2005, J.U.P. Souza et al. 5221, fl. ( ESA) .

Figures

FIGURE 2. Comparison between Harpochilus corrugatus (A.Inflorescence,B–C.Flower-buds,notice corrugatedleaves) andHarpochilus neesianus (D. Inflorescence, E. Detail of branch showing calyx and flat leaves).

FIGURE 4. Distribution map of Northeastern Brazil showing the three species of Harpochilus (H. corrugatus—black dots, H. neesianus— orange dots and H. paraibanus—yellow dots).

FIGURE 5. Nectarivorous Glossophaginae bat visiting flower of H. corrugatus at the Estrada Real, between Livramento de Nossa Senhora and Rio de Contas.