Reestablishment , new records , and a key for the species of Aspidosperma ( Apocynaceae ) from the Brazilian Amazon

As a result of systematic study of the Neotropical genus Aspidosperma (Apocynaceae), we reestablish the species A. centrale and A. duckei, and report A. steinbachii and A. tambopatense as new records for Brazil. We provide taxonomic descriptions of these species along with plates, distribution maps, and information on their conservation status, habitat and phenology. We also provide an identification key for all the species of Aspidosperma from the Brazilian Amazon.

Aspidosperma is one of the most important genera of Apocynaceae in Brazil, due to its ecological, economic (mainly for its timber) and medicinal value (Duarte 1970;Marcondes-Ferreira 1988;Pereira et al. 2016).Fifty-six species of Aspidosperma are reported to occur in Brazil (23 endemic), which makes it the country with the greatest diversity of species (Morales & Zamora 2017; Brazilian Flora 2020 under construction).Species of Aspidosperma occur in almost all Brazilian phytogeographic domains (the exception being the southern grasslands, known as Pampas), with a primary center of diversity in the Amazon (31 spp.) (Brazilian Flora 2020 under construction).

Materials and methods
The study was based on material from the herbaria collections of CEN, ESA, IAN, INPA, MG, R, RB, SPF and UEC [acronyms according to Thiers (2018)], and images of material from the databases Atrium Biodiversity Information System (herbarium CUZ) (AABP Atrium 2018), FMNH Botany Collections (herbarium F) (FMNH 2012), and INCT-Virtual Herbarium of Flora and Fungi (herbaria NY and RON) (speciesLink 2018).Species identifications were confirmed through the analysis of protologues and types, or images of types available at JSTOR Global Plants website (herbaria E, G, K, L, P, PH, S, TDC and U) (Ithaka 2018), and other online collections (herbaria A, GH and MO).
Material was measured using a digital caliper and the software ImageJ (Abràmoff et al. 2004).Vegetative and reproductive structures were observed under a stereomicroscope.The terminology used follows Woodson (1951), Radford et al. (1974) and Marcondes-Ferreira (1988).Data on distribution, habitat and phenology were obtained from herbarium vouchers and field notes.Information on leaf and fruit coloring is based on dried material.Distribution maps were created using ArcGis 10.1 (ESRI 2012) using only confirmed occurrences.We assessed the conservation status of the species in Brazil using the GeoCAT tool (Bachman et al. 2011), while the area of occupancy (AOO) was based on the default cell width (2 km), as recommended by the IUCN Red List guidelines (IUCN 2017).
Material examined: BRAZIL.Amazonas: Manaus, Distrito Agropecuário, 90 km NNE de Manaus, Reserva 1501 (km 41), 6/XII/1991, A. A. Oliveira et al. 261  Distribution and habitat: Aspidosperma centrale occurs in Brazil and Colombia.In Brazil, it is found in the North Region (states of Amazonas and Pará), occurring in forests on hilly terrain (terra firme forest) in the Amazon rainforest.
Phenology: Flowers from April to September and fruits from July to December.
Conservation status: Aspidosperma centrale has an AOO of 68 km 2 and is considered endangered according to IUCN guidelines (IUCN 2017).It has 16 confirmed records for Brazil (.kml file available at https://figshare.com/s/81cefc2ee83949c54a21).
Nomenclatural notes: Among the four materials reported by Markgraf (1935) in the protologue of Aspidosperma centrale, Woodson (1951) selected "Ducke 21593" from herbaria U and US as the lectotype.However, this material should not have been chosen as a lectotype since Markgraf indicated "Ducke 24571" as the type using the phrase "Original der Art".Additionally, the number "24571" is not the collector number of A. Ducke, but rather the catalog number of two specimens in herbarium RB (No. 24571, barcodes RB00535019 and RB00535147).Therefore, the collections from herbarium RB with the catalog number "24571" must be considered the type material of Aspidosperma centrale.To avoid confusion, we elected one of these types as a lectotype, and choose the material "Ducke s.n.", RB No. "24571" with barcode "RB00535019", because it was the best preserved.

Aspidosperma duckei
Material examined: BRAZIL.Acre: Cruzeiro do Sul, margem esquerda, do Rio Juruá, Igarapé Viseu, 21/III/1992, C. A. Cid Ferreira et al. 10882  Distribution and habitat: Aspidosperma duckei occurs in Bolivia, Brazil and Peru.In Brazil, it is found in the North (states of Acre, Amazonas and Rondônia) and in the Central West (state of Mato Grosso) Regions, occurring in forests on hilly terrain (terra firme forest) in the Amazon rainforest, and in the transition zone between the Amazon and the Cerrado.
Phenology: Flowers from September to October and fruits from September to May.
Nomenclatural notes: Woodson (1951) designated the material "Ducke 11040" deposited in herbaria G, P and US as the lectotype, which is one of the five gatherings mentioned by Ducke (1922) in the protologue of Aspidosperma duckei.However, most of the numbers of Ducke's collections are known to actually be catalog numbers of herbaria MG or RB.In the present case, Ducke mentioned in the introduction of the publication that specimen numbers indicate the catalog numbers of the herbarium MG.Thus, the lectotype designated by Woodson is actually "Ducke s.n.", and refers to the specimen deposited in MG (barcode MG011040).
Taxonomic notes: Aspidosperma duckei was considered a synonym of A. macrocarpon Mart. & Zucc. by Woodson (1951) and Marcondes-Ferreira (1988).However, Duarte (1970), in a preliminary version of what would be a new revision for the genus, gave indications that Aspidosperma duckei could be a "good species", distinguishing it from A. macrocarpon by its larger petioles and fruit stipes, and by its tomentose ovary (vs.glabrous).Here, we agree with Duarte and accept Aspidosperma duckei.

New records for Brazil
Our research revealed that the records for Aspidosperma steinbachii and A. tambopatense are new for Brazil.Aspidosperma steinbachii was accepted by Woodson (1951), but Marcondes-Ferreira (1988) synonymized this species and A. tambopatense with A. spruceanum and A. parvifolium A.DC., respectively.However, since Marcondes-Ferreira's revision was not actually published, both species remain accepted, which is supported by our observations of morphological characteristics.Distribution and habitat: Aspidosperma steinbachii was initially described with a distribution restricted to Bolivia (Markgraf 1927), occurring in moist forests in the Amazon rainforest, but later, Woodson (1951) reported it also for Peru.This is the first record of Aspidosperma steinbachii for Brazil, where it is found between southeastern Rondônia and northwestern Mato Grosso states, occurring in forests on hilly terrain (terra firme forest) in the Amazon, and in the transition zone between the Amazon and the Cerrado.
Phenology: Flowers from July to October and fruits in November.
Conservation status: Aspidosperma steinbachii has an AOO of 16 km 2 and is considered endangered according to IUCN guidelines (IUCN 2017).It has only four confirmed records for Brazil (.kml file available at https://figshare.com/s/7922a4239a40c3b300d0).
Nomenclatural notes: According to Melchior (1926), who edited the publication "Plantae Steinbachianae", the material collected by J. Steinbach in Bolivia were managed by herbarium B, among which was the holotype of Aspidosperma steinbachii.However, since this specimen was destroyed in 1943, we elected its best-preserved "isotype" as a lectotype, the material "Steinbach 7261" from herbarium K.
Phenology: Flowers from September to December and fruits from October to December.
Nomenclatural notes: During our studies, we realized that Aspidosperma occidentale of Markgraf (1940) and A. tambopatense of Gentry (1984) represent the same taxon.However, the name Aspidosperma occidentale is a later homonym of the validly published name A. occidentale of Malme (1927), thus making it an illegitimate name.As a result, we consider Aspidosperma occidentale of Markgraf a pro synonym of the validly published name A. tambopatense.
Taxonomic notes: Aspidosperma tambopatense is similar to A. williamii Duarte, mainly in vegetative characteristics, but it can be distinguished by having leaves with flattened secondary veins on both surfaces (vs.prominulous), deltoid corolla lobes (vs.orbicular), and sessile or substipitate follicles (vs.stipitate), with an inconspicuous midrib (vs.conspicuous).
1. Leaves congested at the apex of branches; buds protected by cataphylls .
1'. Leaves arranged along the branches; buds not protected by cataphylls.
3. Leaves glabrescent to glabrous on the abaxial surface .

Figure 1 .
Figure 1.Map indicating (A) South America and (B) the distribution of Aspidosperma centrale Markgr.and A. duckei Huber ex Ducke.