Allamanda alagoana J.W. Alves-Silva & T.S. Coutinho, 2023

Alves-Silva, Jarina Waléria & Coutinho, Thales Silva, 2023, Allamanda alagoana (Apocynaceae), a remarkable new species from Northeastern Brazil, Phytotaxa 613 (2), pp. 187-193 : 188-192

Allamanda alagoana J.W. Alves-Silva & T.S. Coutinho , sp. nov. ( Figures 1 , 2 ).

Similar to Allamanda cathartica Linnaeus (1771: 214-215) , sharing habit, short petioles, calyx without colleters and 5-lobed nectary, but differs by having muricate (vs. long spinose) capsules.

Type:— BRAZIL. Alagoas: Flexeiras, Fazenda Jitituba , 9°24’88’’S, 35°80’09’’W, 15 November 2022, fl. and. fr., J.W. Alves-Silva et al. 1829 (holotype: MAC!; isotype: UFMT!) .

Description: —Shrub with climbing branches, latex white. Branches woody, glabrous, sparsely lenticellate, lenticels slightly verrucose in old branches. Leaves verticillate, 4 per node, disposed along the branches, sessile to short-petiolate, petioles 3–4 mm long when present, intrapetiolar colleters present, subulate; leaf blade membranaceous to chartaceous, 8.5–15.0 × 2.5–3.5 cm, elliptic to oblanceolate, base attenuate, apex acuminate to cuspidate, adaxial surface glabrous, lustrous, abaxial surface glabrous but pubescent only on veins, especially on primary vein; venation brochidodromous, primary vein immersed on the adaxial surface and impressed on the abaxial surface, secondary veins spaced from each other. Inflorescence terminal, dichasial, with 3–4 flowers. Flowers 9.0– 11.5 cm long, pedicel 5–10 mm long, glabrous. Calyx gamosepalous, fused only at the base, foliaceous, greenish, lobes unequal in length, 5.5–10.0 mm × 3.0– 3.5 mm, elliptic to oblanceolate, apex acute, glabrous in both surfaces, colleters absent. Corolla gamopetalous, infundibuliform, yellow, externally glabrous, internally pilose at the stamen insertion, lower tube 30–40 × 4–5 mm, slender, cylindrical, upper tube 20–30 × 30–43 mm, enlarged, tubular-campanulate, lobes 40–43 × 40–45 mm, circular to slightly obovate, glabrous, apex rounded. Stamens adnate to the corolla, subsessile, anthers 5–6 mm long, base sagittate, apex apiculate, glabrous. Ovary superior, 2.0–2.3 × 1.8–2.0 mm, ovoid, glabrous, smooth; nectary surrounding the ovary, 5-lobed, ca. 0.5 mm long; style head ca. 2 mm long, fusiform, slightly constricted in the midline, glabrous. Capsule 6.0–8.0 × 5.5–6.0 cm, dorsoventrally compressed, ellipsoid to slightly circular, muricate, apex mamillate. Seeds 2.5–3.0 cm diam., round, winged, wings chartaceous, undulate, ferruginous.

Etymology: —The specific epithet refers to the endemic distribution of the species in the state of Alagoas, Brazil.

Distribution and habitat: — Allamanda alagoana is known from a few localities in Estação Ecológica Serra de Murici in the state of Alagoas, Northeastern Brazil ( Figure 3 ), a protected area that spans over ten municipalities. The species was found only in the cities of Flexeiras and Murici, growing associated with rock outcrops in open ombrophilous forest in the Atlantic Forest domain, in exposed sites. This area is notable for its plant diversity, where many taxonomic novelties have been found, such as Aspidosperma dardanoanum J.W. Alves-Silva (2021: 272) , Eugenia curuba Costa-Lima & E.C.O. Chagas (2018: 214–215) , Eugenia paumarina Costa-Lima & E.C.O. Chagas (2018: 218) , and Ruellia insurrecta E.C.O. Chagas & Costa-Lima (2020: 46–47) . Allamanda alagoana is the first described species of Apocynaceae endemic to the state of Alagoas.

Phenology: —Collected with flowers and fruits in September and November.

Conservation status: —Due to the small number of populations (≤ 5) occurring in a single area (type locality), Estação Ecológica Serra de Murici, Alagoas state, we suggest classifying the species as Deficient Data (DD), according to the IUCN (2019) criteria. Allamanda alagoana has an AOO of 8 km 2, and its EOO could not be calculated due to lack of information necessary for a proper GeoCat tool analysis. Besides , this species occurs in an area that suffers from issues related to fires, deforestation, predatory activities such as hunting and fishing, and inadequate disposal of solid waste and effluents, which reinforces its classification in the DD criterion. (IMA 2015).

Paratypes: — BRAZIL. Alagoas: Murici, Estação Ecológica Serra de Murici, Fazenda Santa Fé , 14 November 2010, fl., E.C.O. Chagas & M.C. Mota 9444 ( MAC!); Murici, Serra Jitituba , Fazenda Bela Vista , 26 September 2015, fr., J.W. Alves-Silva 1525 ( MAC!). Flexeiras, Fazenda Jitituba , 15 November 2022, 9°24’88’’ S, 35°80’09’’ W, fr., J.W. Alves-Silva 1830 ( MAC!) .

Additional specimens examined: — Allamanda blanchetii : BRAZIL. Alagoas: Água Branca, 01 February 2009, fl. and fr., R.P. Lyra-Lemos et al. 11659 (MAC); ibid., 14 November 2010, fl., E.C.O. Chagas & M.C. Mota 9444 (MAC); ibid., 24 March 2012, fl., E.S. França 66 (MAC); ibid., 14 April 2012, fr., J.W. Alves-Silva et al. 1189 (MAC); ibid., 21 June 2012, fl. and fr., A. Costa 572 (MAC); ibid., 31 August 2013, fr., M.C. Mota 12090 (MAC); Delmiro Gouveia, 23 April 1982, 30 km da cidade, fl., R.P. Lyra-Lemos et al. 649 (MAC); ibid., Margem do Canal do Sertão, 27 April 2014, fl., M.C. Mota 12433 et al. (MAC); Dois Riachos, em direção a Cacimbinhas, 16 March 1980, fr., R.P. Lyra-Lemos et al. 231 (MAC); Maravilha, margem da estrada, 13 August 1982, fl., R.P. Lyra-Lemos et al. 551 (MAC); Major Isidoro, 20 July 1982, fl., R.P. Lyra-Lemos et al. 603 (MAC); Santana do Ipanema, 24 August 1981, fl. and fr., G.L. Esteves et al. 872 (MAC); São Jose da Tapera, AL-220, próximo a cidade, 15 October 1993, fr., C.S.S. Barros 416 et al. (MAC); Traipu, Serra da Mão, 26 November 2009, fl., A. Costa 310 (MAC); ibid., 21 August 2010, fr., R.P. Lyra-Lemos et al. 13172 (MAC). Pernambuco: Belas Águas, Distrito de Ribeiro Alto, 30 June 2015, fl. and fr., T.S. Coutinho et al. 25 (UFP).— Allamanda cathartica : BRAZIL. Alagoas: Messias, 06 November 1980, fl., D. Andrade-Lima 25548 (IPA). Murici, Estação Ecológica Serra do Ouro, 10 April 2014, fl., J.W. Alves-Silva et al. 1474 (MAC). Piaçabuçu, Várzea da Marituba, 20 February 1995, fl., C.S.S. Barros et al. 405 (MAC).— Allamanda doniana : BRAZIL. Alagoas: Ibateguara, Petrópolis, 11 December 2010, fl., J.W. Alves-Silva et al. 839 (MAC). Jequiá da Praia, Reserva Particular do Patrimônio Natural Sinibu, 16 June 2017, fl., E. Lins 25 (MAC). Maragogi, Assentamento Água Fria, 20 August 2006, fl., N.S. Jatobá 16 (MAC). Marechal Deodoro, CESMAC, 15 July 2009, fr., N.R. Santos 19 (MAC). Matriz de Camaragibe, Reserva Particular do Patrimônio Natural Serra D’Água, 05 May 2017, fl., N.R. Silva et al. 3 (MAC). Passo de Camaragibe, BR antes da Cidade, 25 April 2014, fl., J.W. Alves-Silva 1487 (MAC). Piaçabuçu, 21 October 1987, fl., I.S. Moreira et al. 20 (HST, MAC). São Luiz do Quitunde, Reserva Garabu, fl., 28 May 2014, J.W. Alves-Silva et al. 1498 (MAC). Satuba, Escola Agrotécnica Federal, 28 September 2007, fr., F. Cavalcante et al. 226 (MAC). Viçosa, Serra Dois Irmãos, 28 February 2009, fl., E.C.O. Chagas & M.C. Mota 2218 (MAC).

Discussion: —Flowering specimens of Allamanda alagoana were first collected in 2010 and identified as A. cathartica , due to its similarity with the latter when only in flower. In 2015, a second specimen was collected in the same location, containing fruits, which was then compared with the previously collected sample and confirmed to be a new species. Allamanda alagoana differs from A. cathartica by the capsules with muricate (vs. long spinose) surface.

According to Morales (2014), only Allamanda laevis Markgraf (1940: 131) and A. nobilis Moore (1868: 918) , both of which occur in Brazil (Flora e Funga do Brasil 2020), and A. weberbaueri Markgraf (1940: 131) lack long spinose capsules. Allamanda alagoana is distinct from all other Allamanda species because it is the only one showing muricate capsules ( Figure 1E–F ), which appear to be an intermediate state between fully smooth and long spinose fruits. From the species lacking long spinose fruits, Allamanda alagoana differs by 5-lobed nectary and muricate fruits (vs. entire nectary, and smooth capsules) ( Table 1 ). Allamanda alagoana is more similar to A. nobilis , both sharing the shrubby habit, with climbing branches resembling vines, petioles 3–4 mm long, brochidodromous venation, and absence of colleters on the adaxial surface of the calyx base, however, the new species differs specially by the glabrous calyx (vs. pubescent) and glabrous corolla lobes (vs. pilose). Allamanda alagoana differs from A. laevis by the shrubby habit (vs. tree), petioles 3–4 mm long (vs. 5–15 mm long), leaf blade with trichomes only on the veins in the abaxial surface, brochidodromous venation (vs. glabrous leaf blade and craspedodromous venation), calyx lacking colleters adaxially (vs. colleters present), and 5-lobed nectary (vs. entire). From A. weberbaueri , A. alagoana is distinguished by the sessile to subsessile leaves, sometimes with petioles 3–4 mm long (vs. petioles 10–15 mm long), and calyx lacking colleters adaxially (vs. colleters present). All character comparisons are listed in Table 1 .

Regarding the geographic distribution of the species with non-spinose capsules, Allamanda alagoana is endemic to the state of Alagoas, Northeastern Brazil and the Atlantic Forest domain, whereas A. laevis is found in the Northeastern (Bahia) and Southeastern Brazilian regions (Espírito Santo, Minas Gerais, and Rio de Janeiro) in the Caatinga, Cerrado, and Atlantic Forest domains. Allamanda nobilis occurs in Colombia, French Guiana, Venezuela, and Brazil (states of Amazonas, Amapá, Rondônia and Roraima), in the Amazon Forest domain. Allamanda weberbaueri occurs only in Peru, in allopatry with the other three species (Flora e Funga do Brasil, 2020; Sakane & Sheperd, 1986).

Other than A. alagoana , only three species of Allamanda are registered in the state of Alagoas: A. blanchetii , A. cathartica , and A. doniana M̧ller Argoviensis (1860: 11). Allamanda alagoana differs from these species by the muricate, not long spinose capsules, in addition to other characters specified in the identification key below. We observed a population of Allamanda doniana in the Área de Proteção Ambiental Serra de Murici, but in the municipality of Ibateguara, where A. alagoana has not been found and/or recorded.

Figures

FIGURE 1. Allamanda alagoana. A. Habit; B. Flowers; C. Stamens and style head; D. Ovary and nectary; E. Capsule in front view; F. Capsule in lateral view.

FIGURE 2. Allamanda alagoana. A. Habit. B. Detail of the abaxial surface of the leaf blade showing trichomes only over veins. C. Flower. D. Nectary and ovary. E. Capsule in front (left) and lateral (right) view. F. Detail of the capsule projections. G. Seed.

FIGURE 3. Geographic distribution of Allamanda alagoana. Brazil highlighted in light gray andAtlantic Forest phytogeographic domain in dark gray. State of Alagoas is indicated in the smaller map by a black rectangle.