Iridaceae from Serra dos Pireneus , Goiás , Brazil

We present an inventory of Iridaceae species from Serra dos Pireneus, a mountain range with several distinct vegetation types within the Cerrado biome and situated in the mid-east region of Goiás state, Brazil. The samples were collected in situ and surveys of herbaria were conducted. We found nine species of Iridaceae on Serra dos Pireneus, belonging to the following genera: Cipura, Gelasine, Sisyrinchium, Sphenostigma and Trimezia. This study provides a list of all species of Iridaceae recorded in this area including a brief diagnosis, a taxonomic note on Sphenostigma polycephalum, an identification key and an illustrated guide of Iridaceae.


INTRODUCTION
Iridaceae is a family of monocotyledons, belonging to the order Asparagales.The family is monophyletic and can be morphologically distinguished by vegetative and reproductive features, including their ensiform and unifacial leaves, flowers with a petaloid perianth bearing three stamens and inferior ovary and scattered cells containing styloids or cuboidal calcium oxalate crystals in most organs (Goldblatt and Manning 2008;Simpson 2010).
Widespread all over the globe, Iridaceae comprises ca.66 genera and more than 2,000 species, in seven subfamilies (Goldblatt et al. 2008).In Brazil, there is only one subfamily, Iridoideae, with 23 genera and 190 species, mostly distributed in Atlantic Forest, Cerrado and Pampa biomes (Eggers et al. 2016).
The Cerrado, also known as the Brazilian savannah, is mainly located in the Central Brazilian Plateau and is the second largest biome in Brazil.This biome covers two million square kilometers, representing 21% of the Brazilian territory and is considered a hotspot area for priority conservation (Klink and Machado 2005).
Remaining Cerrado areas have decreased over the years, mainly for agricultural expansion, intensified since the 1940s, due to the construction of Brasília, the new capital of Brazil, in 1960 (Pedroso 2004;Miziara and Ferreira 2007;Bastos and Ferreira 2010).In the state of Goiás, for example, native vegetation covers is less than 50% of its original extent; this is worrying because current studies indicate that these natural environments are very susceptible to degradation (Klink and Machado 2005;Rocha et al. 2011).Therefore, biodiversity studies of the Cerrado are one of the most urgent topics on the agenda for conservation biology.
Iridaceae, with three representative genera, Cipura Aubl., Sisyrinchium L. and Trimezia Salib.ex Herb., is commonly found in Cerrado environments.Cipura is a small genus of the Neotropics, with ca. 8 spp.(Celis et al. 2003); Sisyrinchium is the largest genus found all over the Americas (Chauveau et al. 2011;Karst and Wilson 2012) with an estimated 140 spp.(Goldblatt and Manning 2008); and Trimezia is distributed from Paraguay to Mexico (Chukr and Giulietti 2008) with ca.20 spp.
This paper provides a complete list of Iridaceae species recorded from an area of preserved Cerrado in the Serra dos Pireneus, Goiás state, Brazil.An identification key, diagnoses, habitat information, and photographs are presented, making this a database for further studies and a field guide.

Study site
The Serra dos Pireneus (SDP) is located in the municipalities of Pirenópolis, Cocalzinho de Goiás and Corumbá de Goiás (15°40′ S, 048°45′ W to 15°45′ S, 048°50′ W), in the state of Goiás.The minimum altitude is 700 m in Pirenópolis city and the maximum is 1,385 m on Pico dos Pireneus (Figure 1).According to the Köpper-Geiger classification, the region climate is type Aw (Kottek et al. 2006), with annual average rainfall

Lists of species
Dantas-Queiroz et al. | Iridaceae from serra dos Pireneus here provided.The specimens were identified using specialized literature (Celis et al. 2003;Chukr and Capellari Jr. 2003;Chukr and Giulietti 2008;Eggers 2008;Goldblatt and Manning 2008).The descriptions of genera and the nomenclatural terms used were adapted from Goldblatt and Manning (2008) and Harris and Harris (1994).
These species occur mostly on 'campo limpo' vegetation, sometimes also growing in forested environments (Table 2).Species abundance varies across the seasons, and reproductive organs are more common during the rainy season (Figure 2).  1.

Key to species of
Part of the SDP is protected by law within the Natural State Park of serra dos Pirineus.However, this protected area has been subjected to many anthropogenic influences, because all areas of the SDP have touristic, folkloric and religious sites, and there is also intense quartzite mining activities (Siqueira 2004;Bosquetti 2008).

Data collection
Field trips were carried out in various months from 2007 to 2012 in order to locate individuals and observe them in their natural habitats.Collected specimens were deposited at the herbarium UFG.Collections from the herbaria CEN, FLOR, HEPH, HTO, HUEFS, HUEG, HUTO, IBGE, NY, RB, SP, SPF, UB, UFG, and UFRN were also studied.Acronyms are according to Thiers (2016).
Morphological and ecological information were extracted from collected materials from the SDP.Additional materials, when necessary, are properly referenced.The SpeciesLink database was used to assemble a family histogram chart for the study area, including the mean precipitation, along the years (CRIA 2016;INMET 2016).An identification key is Sisyrinchium L. (Linnaeus 1753: 954).Sisyrinchium is the largest genus of Iridaceae in the New World (ca.140) and is quite different in its morphology.Typical rhizomatous herbs, bearing flat or cylindrical leaves and flowers usually with subequal tepals, ranging from white, purple, blue and yellow.Filaments fused at some point, bearing or not trichomes.Style partially fused, with three branches.
Ecology: Sisyrinchium marchio usually occurs isolated or with a few clustered individuals.Blooming from the beginning until the end of rainy season (October to May), one or two flowers at the same time per plant.Tribe Tigridieae Cipura Aubl.(Aublet 1775: 38, t. 13).
The genus Cipura has about eight species, distributed in Central and South America.Their members have bulbous rootstock, plicate leaves, erect or reflexed, and a large bract inserted at the cylindrical flowering stem apex.Flowers are yellow, lilac, purple, blue or, sometimes, white.The inner tepals are smaller than the outer.Stamens are free or sometimes proximally fused and the styles are thickened.Ravenna (Ravenna 1988: 36-37).Figures 5 and 6 Diagnosis: Plants 30-45 cm height.This species has a resiniferous bulb, usually with encrusted rocks on its surface and rigid erect leaves.The flowers are showy, lilac or violet.The outer tepals are reflexed, with small purple dots, while the inner tepals have a white claw (the lower portion) with the upper portion presenting a limb that curves forward over the claw, with a yellow spot, and then is rolled outward distally.

Cipura formosa
Ecology: This species is found in medium to large populations, rarely isolated.Blooming on rainy season (January to May); only one flower at a time per plant.
Ecology: Occurs isolated, rarely forming large populations.This species is found in open vegetation and also in anthropic areas.Blooming on rainy season (January to April); one or two flowers at a time per plant.

Cipura xanthomelas
Ecology: Often isolated or few individuals close to each other.Also found growing in pastures and close to human habitations.Blooming on rainy season (November to March), usually one or two flowers at the same time per plant.
This genus, comprising ca.six species, is distributed throughout South America.The rootstock is a bulb and their leaves are ensiform and pleated.Flowers are usually blue or lilac, with sepals subequal, the inner smaller than the outer.The stamens are adpressed to the style branches, these with the same size or exceeding the height of the anthers.
Ecology: Usually associated with tall grasses.A very rare species to be observed at SDP, found with the flower opened only in the morning.Observed isolated and blooming in February, only one flower at a time per plant.Fruits were observed from January to April.
Sphenostigma comprises ca. 10 species, distributed from the USA to South Brazil, Uruguay, and Argentina.These herbs have a rootstock bulb, ensiform and pleated leaves.Flowers are very fugacious, varying from blue to yellow, with free tepals, more or less subequal.Anthers are larger than the filaments; style is divided into filiform branches, emerging above the anthers.Baker (Baker 1892: 107).Figures 11 and 12 Diagnosis: Plants ca.40-60 cm high, bearing broad, flexuous and plicate leaves.Inflorescence is loose, some -times pendant.The flowers are showy and completely yellow, very fugacious (opens in the morning and closes before the sunset), with fiddle-shaped anthers.

Sphenostigma polycephalum
Ecology: This is a very rare species in the area, found only at Cachoeira das Araras.Occurs in small populations and blooms in the rainy season (December to January) with one or two flower at a time per plant.
Taxonomic note: The name "Sphenostigma polycephala" was created with grammatical error and is current Trimezia, with ca.20 species, is distributed from Central to South America.Plants have a corm-like rootstock, leaves flat or cylindrical and inflorescences congested.Flowers are yellow, orange, blue or lilac; tepals unequal, with complex patterns of markings; outer tepals usually larger and reflexed, while the inner are smaller and usually erect and articulated.Stamens with filaments free and slender; styles are fused, except at stigmatiferous region, this with crests.
Trimezia cathartica (Klatt) Niederl.(Klatt 1862: 549;Niederlein 1890: 332) Figures 13 and 14 Diagnosis: Plants ca.15-30 cm high, bearing cylindrical leaves and a flowering stem with two imbricated bracts close or in the median region.Flowers are orange, with brown stripes from the claws to the median region of inner and outer tepals.
Ecology: This species comprises large populations, with many blooming plants at the same time, forming beautiful "natural gardens".Blooming in the beginning of the rainy season (September to December), usually with one or two flowers at the same time per plant.
Ecology: Large populations were observed, but may also occur isolated, usually close to forest formations.Blooming in the beginning of the rainy season (September to January), with one or two flowers at the same time per plant.

DISCUSSION
Most of species of Iridaceae found in the SDP are consistent with the Brazilian Flora Checklist (Eggers et al. 2016).The species found in the SDP represent 32% of the 22 species found in the state of Goiás.However, according to Eggers et al. (2016), Sisyrinchium marchio was considered synonymous with S. vaginatum subsp.marchio.Regarding this taxon, all herbarium specimens seen were previously identified as S. vaginatum.We decided to follow the Eggers et al. (2016) because their indicated voucher specimen features a great resemblance to the specimens of SDP.However, this taxon has a complex taxonomy, shows wide morphological plasticity, and requires more detailed studies.
Another species with taxonomic problems is Sphenostima polycephalum.Ravenna (1977) held a series of new combinations, including some Sphenostigma species into Gelasine, Cardiostigma and Ennealophus; but S. polycephalum remained without a proper taxonomic characterization.Later, Chukr (2010) conducted a combination of S. polycephalum to Alophia polycephala, but not in accordance to the botanical nomenclature code because the author did not clearly indicate the basionym and the original valid publication.Therefore, A. polycephala remains a nomen nudum (McNeill et al. 2011).Sphenostigma polycephalum apparently is related to Alophia, because both bear fiddle-shaped anthers but lack pollen grains with a verrucate aperture (Goldblatt and Le Thomas 1992;Goldblatt and Manning 2008;Dantas-Queiroz and Luz 2015).This species is in need of taxonomic revision to better establish its position and nomenclature.
Despite being a small area, the SDP presented a representative number of species of Iridaceae, including the rare Sphenostigma polycephalum.As natural Cerrado areas are highly threatened and undergoing quickly being destroyed, biodiversity studies are extremely important for the preservation of this family and the ecosystem as a whole.

Figure 1 .
Figure 1.Map showing the location of Serra dos Pireneus, in the state of Goiás, Brazil.DF -Federal District.

Figure 2 .
Figure 2. Histogram of all collected vouchers of Iridaceae with reproductive organs along the years 1900-2012 (blue bars, right) and the mean precipitation on Serra dos Pireneus, in mm (orange line, left).

Table 1 .
Vegetation description found on serra dos Pirineus, Goiás State, Brazil.CH Grassy layer composed by many herbs.Water table rises during the rainy season and it is often waterlogged, falling drastically during the dry season.
Cerrado stricto sensu (wooded grassland) CT Forest vegetation, with grassland characteristics and marks of fires.Trees are small, tortuous and twisted, shrubs and subshrubs are sparse, some species present perennial rootstock (geoxyle).

Table 2 .
Species of Iridaceae from SDP and their respective vegetation occurrences.For vegetation acronyms and description consult Table1.
Plant ca.30-50 cm high, bearing flat and linear leaves.Has a long bract in the flowering stem, exceeding the length of leaves.Flowers are pale yellow, with a short peduncle, usually sinuous.The styles are wider in the middle region Ecology: Usually occurs isolated, not growing in large populations.Blooming in the rainy season (December to March), with only one flower at a time per plant.