Vanilla bahiana Hoehne and Vanilla pompona Schiede (Orchidaceae, Vanilloideae): two new records from Maranhão state, Brazil

We present here the first records of Vanilla bahiana and Vanilla pompona from Maranhão state, northeastern Brazil. Both species were collected in a gallery forest, in areas of Cerrado vegetation at Caxias municipality. This work contributes with knowledge on the geographical distribution of the species in northeastern Brazil.


Introduction
Orchidaceae is the most representative monocot family in terms of number of species. The family currently has ca 27,000 identified species and 736 genera distributed worldwide, with this number increasing every year (Govaerts 2014, Chase et al. 2015). Brazil has ca 10% of that amount, that is, 2499 species (1599 endemic/ca 64% of the total) which are distributed in ca 220 genera (28 endemic/ ca 13% of the total) (BFG 2015, Brazilian Flora 2017. Pabst andDungs (1975, 1977) reported only 10 species from the Brazilian state of Maranhão. Silva et al. (1999) reported 103 orchid species in the region, distributed over 48 genera. More research on the Orchida-ceae has been carried out in Maranhão after the study conducted by Silva et al. (1999), and currently 122 species and 53 genera of orchids (Brazilian Flora 2017) are reported to the state.
Vanilla Plumier ex Miller has pantropical distribution and encompasses ca 100 terrestrial, hemiepiphytic, or occasionally epiphytic species, which can grow up to ca 25 m in length (Cameron 2003, Soto-Arenas 2003, Soto-Arenas and Cribb 2010, Soto-Arenas and Dressler 2010. The flowers of Vanilla species usually last less than 12 h open; they can be white, greenish white, beige, or even yellow; and yield pod-like fruits. Some of the species are grown for vanillin, which is obtained from their mature fruits. Species of Vanilla occur in tropical and subtropi-

NOTES ON GEOGRAPHIC DISTRIBUTION
cal regions of Africa, Asia, and America; it is absent in Australia. Most species are found in tropical America, followed by southeastern Asia, Africa, and islands in the Indian and Pacific Oceans (Cameron 2003, Soto-Arenas 2003, Soto-Arenas and Cribb 2010, Soto-Arenas and Dressler 2010, Pansarin et al. 2012, Chase et al. 2015. A total of 37 species of Vanilla occur in Brazil (Brazilian Flora 2017), including the newly discovered Vanilla arcuata Pansarin & M.R. Miranda (Pansarin and Miranda 2016), V. capixaba Fraga & D.R. Couto, and V. paulista Fraga & Pansarin (Fraga et al. 2017). Ten of those species are found in the northeast region of the country (Sanbim andChiron 2015, Brazilian Flora 2017).
Among the species previously known from the state of Maranhão are Vanilla mexicana Mill., V. palmarum (Salzm. ex Lindl.) Lindl., and V. planifolia Jacks. ex Andrews (Brazilian Flora 2017). Records of V. bahiana Hoehne and V. pompona Schiede are the first from the state and extend the ranges of both species.

Methods
The Municipal Environmental Protection area of Inhamum (APA Inhamum) and the Primavera town are located in the municipality of Caxias, state of Maranhão, Brazil, both areas with gallery forests included in areas of the Brazilian Cerrado (Fig. 1). The APA Inhamum (04°53ʹ30ʺ S, 043°24ʹ53ʺ W; ca 3500 ha) is located in the municipality of Caxias, in eastern Maranhão, Brazil (Fig.  1). The APA Inhamum is covered primarily by Brazilian Cerrado (Brazilian savanna), with 2 distinct types of vegetation (shrubby-arboreal and grassland) on the flatter terrain, with stands of buriti palms (Mauritia flexuosa L. f. Arecaceae) associated with watercourses, in depressions (gallery forests) (Neres and Conceição 2010). A town, Primavera (04°50ʹ32ʺ S, 43°29ʹ29ʺ W) ( Fig. 1), is located approximately 8 km from the APA Inhamum and has forest fragments, including gallery forest, with the same characteristics as inside the protected area. Fieldwork in the gallery forests was carried out between December 2015 and December 2016 as part of the project "Orchids from Maranhão: taxonomy, pollination systems, and in vitro propagation" (Universal Announcement FAPEMA 0043/2015).
Collected specimens were identified following Hoehne (1950), Soto-Arena and Dressler (2010), Pessoa and Alves (2012,2015), BFG (2015), and the online databases Brazilian Flora (2017), Tropicos (2017), and SpeciesLink (2017), which were also used to the determine the geographical distributions of the species. A specimen of each species of Vanilla was deposited in the HENAC herbarium (Federal University of Maranhão, Codó, Brazil) and in the MAR herbarium (Federal University of Maranhão, São Luís, Brazil). The herbarium acronyms follow Thiers (2017). Morphological descriptions, photographic plates, and the map with the collection site of both species are provided, as is the taxonomic key to Vanilla species from Maranhão.
Note. In the SpeciesLink database there is a citation for a collection of V. pompona from state of Maranhão [Balick, M.J. 1481 (INPA 127516)]. The cited collection is a sterile specimen and after studying it we concluded that it is not possible to confidently assign it to V. pompona. In addition, the leaf form of this sterile specimen is lanceolate, whereas in V. pompona it is oblong. Moreover, the fact that it was collected associated with Orbignya (babassu palm) and is considered common in this place, suggests that it might be Vanilla palmarum (Salzm. Ex Lindl.) Lindl., an epiphytic species commonly associated with babassu palm in Maranhão.
Vanilla bahiana is a native species endemic to Brazil and the species was described from the state of Bahia (Hoehne 1950    Floral bract size 0.5-0.9 × 0.5-0.7 cm 1.0-1.4 × 1.0-1.3 cm Sepal and petal color Yellowish-green Yellow Lateral sepal size 1.1-1.5 × 8.1-8.5 cm 0.7-1.2 × 6.7-8.5 cm Petal size 0.7-0.9 × 7.3-7.6 cm 0.8-1.3 × 6.5-9.2 cm Column size 0.5 × 5.3-5.5 cm 0.3-0.4 × 6.3-6.5 cm Labellum size 2.0-2.2 × 6.4-6.9 cm 2.4-3.0 × 6.7-8.0 cm Flowering season September to January July to August occurrence (EOO) of 2,174,496.018 km 2 and an area of occupancy (AOO) of 452 km 2 (Fig. 4) was obtained. Based on 26 collections of V. pompona representing 18 localities, we obtained an extent of occurrence (EOO) of 3,546,277 km 2 and an area of occupancy (AOO) of 64 km 2 (Fig. 5). Although both species are widespread across their distribution, most populations are reported from the Atlantic forest, where habitats are severely fragmented, and the suitable habitats may experience decline in quality due to further deforestation, which may in turn affect the survival of the species. Therefore, V. bahiana and V. pompona are both assigned a preliminary status of "Endangered" under criteria ENB2ab(ii). Thus, our results illustrate that more collection efforts are needed to increase knowledge on orchids and their distribution by reducing geographical gaps (BFG 2015, Brazilian Flora 2017.