Vanilla palmarum (Salzm. ex Lindl.) Lindl.

Vanilla palmarum (Salzm. ex Lindl.) Lindl. View in CoL

Figs 2 View Figure 2 , 3 View Figure 3 , Table 1 View Table 1

Epidendrum palmarum Salzm. ex Lindl. View in CoL

Vanilla palmarum var. grandifolia Cogn. View in CoL

Type.

BRAZIL • Bahia, s. loc.; s. d.; P. Salzmann s. n.; isotypes: K [ K 000293255 ], MPU [ MPU 013457 , MPU 018359 , MPU 018360 ], G [ G 00190804 , G 00190913 ] .

Description.

Epiphytic herbs, long scandent. Roots axillary, one per node; aerial roots 1–1.5 mm diam., velamenous, glabrous, simple, whitish to creamy; storage roots up to 4 mm diam., branching, white. Stem climbing, sinuous, cylindrical, fleshy, glabrous, glaucous to green with whitish dots; internodes 25–50 × 2.5–5 mm. Leaves 3.5–8.5 × 2–4 cm, alternate, distichous, elliptic to ovate, symmetric or asymmetric, fleshy, glabrous, glaucous to yellowish green, margin entire, apex acute to acuminate, pseudopetiolate; pseudopetiole concave, 3–5 mm long. Inflorescence 1.8–2.5 cm long, apical, racemose, pending, with up to 10 flowers opening in succession; 1 flower opening each morning; bracts 5–15 × 3–8 mm, progressively smaller toward the apex, alternate, triangular to elliptic, coriaceous, concave, patent, apex acute, sometimes leafy. Flowers resupinate, pedicellate, with an abscission layer between perianth and ovary; pedicel with ovary 2.3–2.6 × 0.4–0.6 cm, straight to incurved, calyculate, subcylindrical in transverse section, white along the pedicel and green along the ovary. Sepals 4.7–5.1 × 0.9–1.1 cm, free, oblanceolate, fleshy, slightly concave, internally pale yellow, externally yellow, apex obtuse, margin entire, reflexed at apex; dorsal sepal symmetric; lateral sepals asymmetric. Petals 4.8–5.1 × 1.2–1.4 cm, free, spatulate, asymmetric, membranous, apex acute, slightly reflexed, yellow, adaxial surface with a central and longitudinally arranged keel. Labellum 1 - lobed to slightly 3 - lobed, 5.1–5.3 × 3.9–4.1 cm, unguiculate, tubular, yellow, whitish in the basal portion, inner surface with longitudinal prominent stripes converging in two triangular protuberances and in a cluster of the digitiform secretory trichomes at the entrance of the nectar chamber; central crest (nectar guide) ca 5 mm wide near the apex, and with an elevation ca 4 mm wide (convex) just below the anther and stigma; labellum margins fused from the base to ca ¾ of the column length forming a tubular nectar chamber; nectar chamber 1.3–1.6 cm long; lateral lobes obliquely rounded, margins undulate; apical lobe emarginated, reflexed, margin undulate. Column 3.4–3.6 × 0.34–0.37 cm, semi-cylindrical, slender, base attenuate, dilated towards the apex, with white-hyaline hairs close to the stigma, apex with two lateral projections (wings) facing upward; anther 3.6–3.9 × 3.5–3.8 mm, rhomboid, yellowish, versatile; rostellum 3.8–4 × 3.5–3.8 mm, trapezoidal, white. Fruits 4.4–6.5 × 0.8–1.4 cm, linear, incurved, diamond-shaped in transverse section, fleshy, dehiscent, opening in two valves, green when immature, yellowish when mature. Seeds ca 0.5 mm, crustose, ovate, black.

Distribution and ecology.

Vanilla palmarum is a Brazilian endemic species widely distributed in the Caatinga and Atlantic Forest Biomes, occurring in open forests of north-eastern Brazil (Fig. 3 View Figure 3 ). Vanilla palmarum has an epiphytic habit, rooting on the trunk of several palm species of the genera Elaeis Jacq. and Syagrus Mart. ( Barberena et al. 2019; Table 1 View Table 1 ). The elevation is from 212 to 1123 m a. s. l. Flowers open in morning hours and each flower lasts ca 12 hours. As in V. lindmaniana ( Pansarin and Ferreira 2022) , the flowers of V. palmarum offer nectar as a reward which is stored in the nectar chamber. Flowers of V. palmarum also shows a mechanism of facultative self-pollination. Its flowers are chasmogamous but in the absence of biotic pollination, flowers self-pollinate (Emerson Pansarin unpubl. data). Although V. lindmaniana is pollinated by hummingbirds ( Pansarin and Ferreira 2022), the flowers of V. palmarum do not appear to be adapted for avian pollination as their central crest (nectar guide) is convex. In V. lindmaniana , the labellum shows a channel-like depression of ca 2 mm wide, whose function is to guide the hummingbird’s bill to the entrance of the nectar chamber ( Pansarin and Ferreira 2022).

Phenology.

Vanilla palmarum blooms from December to February. The fruits ripen between July and September.

Preliminary IUCN conservation assessment.

Endangered: EN B 2 a (ii, iii). Vanilla palmarum is a rarely collected species currently known from the Atlantic Forest and Caatinga Biomes of Brazil. The extent of occurrence (EOO) is estimated to be 657,099 km 2, which falls within the limits for Least Concern (LC), according to the IUCN Red List categories and criteria and guidelines. The area of occupancy (AOO) is estimated to be 108 km 2 (cell width of 2 km), which falls within the limits for Endangered (EN) under criterion B 2 (area of occupancy). Considering that both the Atlantic Forest and Caatinga Biomes have been reduced to scattered fragments due to extensive human occupation, we project a continuing decline in (ii) area of occupancy and (iii) extent and / or quality of the habitat of V. palmarum . Based on these threats, V. palmarum is assessed as Endangered (EN).

Additional material examined.

BRAZIL – Alagoas • Maceió, Serra da Saudinha, Fazenda Cela ; 10°05’37”S, 36°11’28”W; 13 Jan. 2008; Chagas-Mota 243; MAC GoogleMaps . – Bahia • Amargosa, Recôncavo Sul, entrada da porteira da Fazenda Acaju ; 11°01’00”S, 39°36’00”W; 27 May 2005; M. A. Costa & M. L. Guedes 14; ALCB GoogleMaps • Boa Nova, Parque Nacional de Boa Nova, setor central, Fazenda Alvorada, Lajedo dos Beija-flores ; 14°21’45”S, 40°12’27”W; 1215 m; 2 Mar. 2013; L. Y. S Aona 2149; HUEFS GoogleMaps • Caetité, Coleta arredores da área de preservação da Indústria Nucleares do Brasil - INB, Áreas 1 - Margem direita da Reserva Próximo a Lagoa, 2 - Barragem Wilson Gouveia, 3 - “ Mulungu ”; 14°04’09”S, 42°28’29”W; 26 Sep. 2009; J. L. Paixão 1552; HUEFS GoogleMaps • Cravolândia, Sudoeste, Assentamento Palestina ; 13°23’25”S, 39°49’13”W; 14 Aug. 2001; L. de J. Alves et al. 354; ALCB GoogleMaps • Feira de Santana, Campus da Universidade Estadual de Feira de Santana ; 12°12’01”S, 38°58’18”W; 5 Apr. 2018; M. F. Alves & J. L. Mayer 5; UEC GoogleMaps • Campus da UEFS, Atrás do Centro Administrativo ; 12°12’05”S, 38°58’05”W; 6 Oct. 1997; I. F. Castro et al. 31167; UB GoogleMaps • Itatim, Morro do Agenor ; 12°42’42”S, 39°41’53”W; 26 Nov. 1995; F. França 1465; HUEFS GoogleMaps • Itatim, Fazenda na base do morro das Tocas ; 12°42’42”S, 39°41’53”W; 282 m; 31 Aug. 2003; T. B. Cavalcanti 3190; CEN GoogleMaps • Jacobina, Paraíso, Fazenda Exú ; 11°10’50”S, 40°31’05”W; 11 Aug. 2006; s. col. 11223; EAN [ EAN 21562 ] GoogleMaps • Saubara ; 12°44’15”S, 38°46’07”W; 15 Aug. 2017; K. Martins & A. Figueiredo 13; HST GoogleMaps • Jacobina, Piemonte da Diamantina, Arredores do Povoado de Tamanco ; 11°10’50”S, 40°31’05”W; 28 Apr. 2012; T. L. Vieira et al. 91; ALCB GoogleMaps • Lajedinho, Chapada Diamantina ; 12°21’20”S, 40°54’20”W; 23 Aug. 2014; G. S. Silva et al. 633; HUESB GoogleMaps • Milagres, Serra do Jatobá ; 12°52’11”S, 39°51’32”W; 21 May 2021; L. Y. S. Aona 5955; HURB GoogleMaps • Retirolândia, Fazenda Piabas, próximo ao riacho ; 11°29’41”S, 39°25’32”W; 212 m; 1 Nov. 1999; R. P. Oliveira 308; HUEFS GoogleMaps • Salvador, Região Metropolitana de Salvador, Ilha de Maré, Povoado de Bananeiras ; 12°44’58”S, 38°31’42”W; 12 Jun. 2011; M. L. Guedes et al. 18375; ALCB GoogleMaps • Sento Sé, Parque Nacional Boqueirão da Onça, Entrada para Alegre, Vindo do Povoado Almas ; 09°44’45”S, 41°53’06”W; 1123 m; 4 Sep. 2013; D. S. Fernandes 86; HVASF GoogleMaps • Valente, Mata nativa, localizada a 4 km do centro, sentido a saída para Retirolândia ; 11°26’29”S, 39°27’18”W; 326 m; 10 Jun. 2017; M. R. L. Constantino 33; MBML GoogleMaps • Umburanas, PNBO, Umburanas ; 723 m; 22 Sep. 2006; J. A. Siqueira Filho 1799; HVASF • Wagner, Mata ciliar do rio Tijuco ; 12°13’32”S, 41°15’24”W; 17 Nov. 2018; E. B. Lopes & M. L. Guedes 71; ALCB GoogleMaps . – Ceará • Viçosa do Ceará ; 03°33’43”S, 41°05’31”W; 29 Dec. 2005; A. S. F. Castro 1661; EAC GoogleMaps . – Minas Gerais • Salto da Divisa, Fazenda Santana ; 16°04’16”S, 40°03’19”W; 137 m; 20 Feb. 2003; J. A. Lombardi et al. 5105; BHCB GoogleMaps . – Paraíba • Barra de Camaratuba, Estrada Rural ; 06°36’37”S, 35°05’58”W; 42 m; 17 Jul. 2014; J. M. P. Cordeiro et al. 269; EAN GoogleMaps . – Pernambuco • Arcoverde, Descobrimento, Assentamento Serrote Redondo, Corredor Ecológico Ramal do Agreste e Pacuera Ipojuca ; 08°21’12”S, 36°57’38”W; 947 m; 5 Aug. 2019; A. P. Fontana & J. M. dos Santos 10946; HRSN GoogleMaps • Buíque, Catimbau, trilha das torres ; 08°37’00”S, 37°10’00”W; 17 Oct. 1994; E. Menezes 16; K [ K 000293254 ] GoogleMaps . – Sergipe • Lagarto, Povoado Brejo ; 10°55’02”S, 37°38’59”W; 24 Aug. 2009; L. A. S. Santos & F. B. Suzart 1; ASE GoogleMaps .

Notes.

Vanilla palmarum was described based on specimens collected in the state of Bahia, north-eastern Brazil. Vanilla palmarum has been assumed to be a widely distributed species, from Cuba to south-eastern Brazil. However, according to the data presented here, this taxon is endemic to Brazil, occurring in areas in the Caatinga and Atlantic Forest Biomes. The hypothesis of the occurrence of V. palmarum in Cuba requires careful further investigation. Two Vanilla names were described based on plant material collected in Cuba, namely V. savannarum Britton and V. lutea C. H. Wright ex Griseb. Although both taxa were synonymized under V. palmarum , they appear to be more closely related to V. lindmaniana . In addition, even though V. lindmaniana was published later than V. lutea , the latter is not a validly published name (e. g. BFG 2018). Vanilla savannarum was published later than V. lindmaniana , and therefore would be a synonym of this species. However, until fresh material is available for analysis, it seems to be prudent not to consider V. savannarum as a synonym of V. lindmaniana or V. palmarum . According to the infrageneric classification of Soto Arenas and Cribb (2010), V. palmarum is a member of the V. palmarum group.

Morphological affinities.

Vanilla palmarum is easily recognized from other Neotropical species by its epiphytic habit on palm trees, by its terminal and pendant inflorescences, by its yellow flowers, by the absence of a penicillate callus on the labellum, and by its dehiscent and scentless fruits. Although closely related to V. lindmaniana , V. palmarum is easily distinguishable from it by its distribution in the Atlantic Forest and Caatinga Biomes, by its smaller vegetative and floral structures, the presence of a convex central crest (nectar guide) just below the anther and stigma, and the smaller fruits, which are diamond-shaped in transversal section (Table 1 View Table 1 ).