Flora of Paraíba State , Brazil : Aechmea Ruiz & Pav . ( Bromeliaceae )

Aechmea is one of the largest genera of Bromeliaceae, having more than 250 species, and Brazil is its principal center of endemism. We taxonomically examined the species of Aechmea encountered in Paraíba State in northeastern Brazil. Our analyses were based on specimens collected during the present study, as well as examinations of local and regional herbaria collections. Eleven species were encountered to State: Aechmea aquilega, A. chrysocoma, A. costantinii, A. emmerichiae, A. eurycorymbus, A. fulgens, A. leptantha, A. mertensii, A. nudicaulis, A. patentissima, and A. werdermannii. Of those taxa, seven are endemic to northeastern Brazil and five are included within one of the threatened categories according to IUCN criteria, two of them being “endangered” and “critically endangered”. We include here a key to the identification of the species, a list of the materials examined, commentaries concerning the taxonomic affinities of the species based on morphological characters, data concerning their geographic distributions, flowering, fruiting, inferences concerning their conservation statuses, as well as images and drawings indicating their principal characteristics.


Introduction
Bromeliaceae A. Juss.comprises approximately 3140 species distributed into 58 genera (Givnish et al. 2011), with predominately Neotropical distributions (Smith & Downs 1974).Brazil is one of the principal centers of diversity of the family, having representatives of more than 70% of the genera and 40% of the species (Wanderley et al. 2007, BFG 2015).Among the eight currently recognized subfamilies of Bromeliaceae (Givnish et al. 2007, Givnish et al. 2011), Bromelioideae demonstrates the greatest diversity, comprising more than 50% of the genera of the family (Smith & Downs 1979, Barros & Costa 2008).
Aechmea Ruiz & Pavón ( 1794) is recognized as the largest genus of Bromelioideae, with more than 250 species (Luther 2008) distributed throughout the tropical Americas (Smith & Downs 1979); 184 of its species occur in Brazil, with 159 being endemic to that country (BFG 2015) -although only 49 of those taxa have been evaluated in terms of their conservation statuses (Martinelli & Moraes 2013).Aechmea has been found to be problematic in terms of its infrageneric classification and poorly established conceptual limits, being considered an artificial group (Wendt 1997, Faria et al. 2004, Barros & Costa 2008) with controversial circumscriptions (Sousa & Wanderley 2015).
The high representivity of bromeliads in greatly threatened Brazilian ecosystems such as the Atlantic Forest and Caatinga (BFG 2015) and the extreme ecological importance of bromeliads in maintaining many biological processes (Benzing 2000), calls for more attention to be paid to studies of the morphologies and distributions of Aechmea species, as well as the family itself.Bromeliaceae is considered the second most numerous family in Brazil in terms of the numbers of threatened species, with the highest number of species considered "critically threatened" (Martinelli & Moraes 2013) -intensifying the necessity for more indepth studies of its component taxa.There have been relatively few studies concentrating on this family (and genus) in Paraíba State, with only the studies of Pontes (2005) of the Atlantic Forest region a synopsis of the genus in three northeastern states by Maciel et al. (2015), and a study of the family on rocky outcrops (Silva et al. 2015).
As such, this work presents a taxonomic study of Aechmea (Bromeliaceae) for Paraíba State, northeastern Brazil providing up-to-date information concerning morphological, taxonomic, and phenological aspects of its species as well as their distributions, which can be used for preparing management and conservation plans for bromeliads in that region.

Materials and Methods
Paraíba State (-06º00'11'' to -08º19'54'' and -34º45'50'' to -38º47'58'') covers 56.440 km 2 , corresponding to 3.3% of northeastern Brazil.The region receives high levels of solar radiation, has a hot climate with a mean annual temperature of 26 ºC and a mean annual rainfall rate >1600 mm.The State have four principal natural ecosystems that have been impacted by different, but intense, anthropogenic modifications: Coastal Plains, Forests, Transition Zones, and Caatinga.The forest formations include Caatinga, those found on coastal plains, mangrove swamps, humid forests, semi-deciduous forests, Atlantic Forest, and near-ocean sandy restinga forest stands (AESA 2006).
Field collections were made on a monthly basis by way of random walks through the greatest possible number of municipalities in the state during the period between May/2015 and May/2016.During these excursions we obtained fertile specimens (with flowers and/or fruits) and recorded field data such as habitat and the colors of the reproductive structures -among other aspects important for identifying the species and characterizing their environments.The collection points were recorded using a hand-held GPS.Reproductive structures (flowers and fruits) were preserved in 70% alcohol in the field for posterior examination in the laboratory.The collections were appropriately processed and incorporated into the Manuel de Arruda Câmara Herbarium (ACAM).
Comparative analyses were made with preserved herbarium specimens in different herbaria (EAN, IPA, JPB, PEUFR, and RB) and also with images from virtual herbaria (B, HVASF, NY, UFP) (acronyms Thiers 2016) available on the JSTOR and Species Link platforms.The description of the genus was based on the species encountered in Paraíba State, and the flowering and fruiting data considered both our field records and herbaria labels.The terminology utilized follows Smith & Downs (1979), Sousa & Wanderley (2000) and Gonçalves & Lorenzi (2011).Inferences concerning the degrees of conservation of the species were based on available information on the Species Link and JSTOR databases as well as on information gathered in the various herbaria visited, and were used to characterize the conservation status of the species according to IUCN (2001) criteria.

Results and Discussion
The genus Aechmea was represented in the Paraiba State by 11 species, of which nine are endemic to Brazil, and seven restricted to northeastern Brazil.Most of the species were restricted to the eastern region of Paraíba State.
The conservation statuses of all species encountered, according to IUCN (2001) criteria, included eight in the "Vulnerable", "Endangered", or "Critically Endangered" categories; one was considered "Almost Threatened" and two "Least Concern".
Phenology: Flowering recorded in November and December and fruiting in July.Distribution and habitat: Endemic to Brazil, occurring in the northern, northeastern, and southeastern regions of that country.Distributed in the eastern region of the country from Ceará State to Espírito Santo State, and in the extreme west in Amazonas State, being found in the Amazonian, Caatinga, Cerrado and Atlantic Forest domains (BFG 2015).In Paraíba State, was recorded in the present study in Brejos de Altitude, in the municipalities of Arara, Dona Inês, and Picuí (Figure 2a), and reported by Pontes et al. (2010) for the municipalities of Bayeux, Caaporã, and Mamanguape.
Conservation status: Pontes et al. (2010) considered this species to be "Vulnerable".However, as it is well-represented in the herbaria collections visited, widely distributed within Brazil, and occurs in several phytogeographical domains (BFG 2015), according to the criteria proposed by the IUCN ( 2001), its conservation status can be considered of "Least Concern" (LC).
Conservation status: Due to its restricted distribution, insufficient records from conservation areas, and endemism associated with one of the three most globally threatened ecosystems, this taxon is considered here as "Vulnerable", with an occupied area estimated to be less than 2000 km² and fragmented into at least 10 areas, with accentuated fluctuations in its extent of occurrence (B2a, ci).

Aechmea costantinii
Distribution and habitat: Species endemic to northeastern Brazil, occurring in the states of Alagoas, Paraíba, and Pernambuco (BFG 2015).Found as an epiphyte in an area of humid forest, municipality of Areia (Figure 2a), "brejo paraibano" region and, according to herbarium consultations, it can also be found as a terrestrial plant.
Conservation status: Although this taxon is well-represented in the herbaria visited, its occurrence can be considered restricted as it is associated with the highly fragmented Atlantic Forest domain, and is only encountered in three Brazilian states.As such, and according to IUCN (2001) criteria, this taxon is considered here as "Vulnerable" (NT), in light of its restricted area of occupation and the accentuated fluctuations of its extension of occurrence, as well as the low numbers of recorded sightings (criterion B2cI, III).
Phenology: Flowering recorded in December and fruiting in December and April.
Distribution and habitat: Aechmea emmerichiae is endemic to Brazil, occurring only in the states of Bahia and Paraíba (BFG 2015).Pontes (2005) reported it for the first time to Paraíba, municipality of Maturéia (Figure 2b), on rock outcrops fully exposed to the sun or as a facultative epiphyte.
Conservation status: According to IUCN (2001) criteria, its restricted distribution to only two states in Brazil (Read & Luther 1991, Leme & Siqueira-Filho 2006, Maciel et al. 2015, BFG 2015).Combined with the accentuated declines of the Caatinga and Atlantic Forest domains, we consider this species "Endangered" in light of its small area of occurrence (500 km 2 ), and accentuated decreases in its distribution and habitat quality (B2bIII).
Phenology: Flowering in April and July and fruiting in April and May.
Distribution and habitat: According to Sousa & Wanderley (2000), Aechmea fulgens can be found in the Brazilian states of Pernambuco, Bahia, and Rio de Janeiro.In the Species List of the Brazilian Flora (BFG 2015), however, it was cited only for the states of Paraíba, Pernambuco, and Alagoas; the latter circumscription is adopted here.
Conservation status: Aechmea fulgens was only encountered in a fragment of Atlantic Forest in the municipality of Natuba, Paraíba State (Figure 2b), where it constituted large populations and demonstrated terrestrial and epiphytic habits, being considered a rare species in the study area.In agreement with Pontes et al. (2010), the conservation status of A. fulgens in the present study is considered "Vulnerable" (IUCN 2001), due to its limited area of occurrence, high fragmentation, and being known from less than 10 localities (criterion B2a).
Phenology: Flowering from January to April, with fruiting extending from de February to December.
Distribution and habitat: Restricted to the states of Alagoas, Paraíba (Figure 2b), and Pernambuco, in northeastern Brazil.Growing on rock outcrops or as facultative epiphytes, forming large populations in trees such as Artocarpus heterophyllus Lamarck (Moraceae), a naturalized species popularly known as "jaqueira" (BFG 2015).
Conservation status: In light of its restricted area of occurrence, and continuous declines and growing fragmentation of the Caatinga and Atlantic Forest environments where its populations occurs, this taxon is considered here as "Vulnerable" (IUCN 2001), criterion B1bIII.
Conservation status: Due to its wide distribution, Aechmea mertensii is considered here of "Least Concern" (LC), a category which comprises the most abundant taxa, according to IUCN criteria (2001).This species is, however, included in the Red List of the Phanerogam Flora of Columbia (Betancur & García 2006) and, as it occurs in highly threatened domains (the Amazon and Atlantic Forests), it is important to draw attention to its populations in those environments.
Conservation status: Considering that this species is endemic to the Atlantic Forest, restricted to three states in northeastern Brazil, and represented by few records in the herbaria collections, it is considered here as "Vulnerable" (IUCN 2001), as its distribution is restricted, it has high potential for harvesting/collecting, and therefore at high risk for extinction in nature.
Commentaries: Aechmea nudicaulis var.nordestina differs from the type-species by its pale (vs.red) scapes and scape bracts, and its greenish-yellow sepals (vs.yellow or spotted with red), this being the morphological pattern found in northeastern Brazil (Leme & Siqueira-Filho 2006).It can be distinguished from the other taxa of Aechmea of this study area by having imbricate scape bracts at the base of the inflorescence, a simple inflorescence with a white-tomentose indument, and all of the flowers sessile.