Syagrus carvalhoi B.F. Sant'Anna-Santos, 2023

Sant'Anna-Santos, Bruno Francisco, Micheli, Rafael, Carvalho, Luiz Fernando Lima & Soffiatti, Patricia, 2023, A new bluish-leaved Syagrus (Arecaceae) from an overlooked OCBIL in the Espinhaco Range (Brazil), Plant Ecology and Evolution 156 (2), pp. 129-145 : 129

Syagrus carvalhoi B.F. Sant'Anna-Santos sp. nov.

Figs 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8

Diagnosis.

Syagrus carvalhoi is similar to Syagrus cabraliensis (Noblick & Lorenzi) B.F. Sant’Anna-Santos, from which it differs by larger, taller clumps (sometimes with colonial habit); taller plants; leaves bluish and straight (vs dark green and slightly arched); pinnae inserted at various angles near the base but otherwise regularly arranged on the upper part of the leaf towards the tip (vs inserted at various angles throughout the entire rachis); pinnae with symmetric tip (vs asymmetric tip); pinnae glaucous on adaxial surface (vs pinnae glossy on adaxial surface); the presence of inconspicuous ramenta (vs without ramenta); rachillae of different sizes throughout the rachis (vs similar-sized rachillae); staminate flowers briefly pedicellate and filaments briefly connate at the base (vs staminate flowers long pedicellate and stamens with free filaments).

Type.

BRAZIL - Minas Gerais • Buenópolis, Parque Estadual da Serra Cabral ; 17°57 ’13.41” S, 44°15 ’2.46” W; 1044 m; 8 Jan. 2021; fl., fr.; Sant’Anna-Santos 377; holotype: UPCB; isotypes: DIAM, IBGE, MBM, UFG .

Description.

Small palm, clustering to colonial, 100-140(-160) cm tall. Stem 30-60 × 7-9 cm, subterranean or prostrate, rarely erect, sometimes forking at or below the ground. Leaves pinnate number 6-13; sheathing leaf base ca 6-16 cm long; pseudopetiole 10-21 cm long; petiole 8-15 × 0.4-0.7 cm and 0.2-0.4 cm thick, abaxial side of petiole and rachis with scarce white tomentum; rachis 43-83 cm long; pinnae bluish-green on both surfaces, glaucous on both sides, pinnae narrow, single-folded and almost linear, fold quickly during drying, pinnae numbering 19-26 pairs, in clusters of 2-3, inserted at various angles near the base but otherwise regularly arranged on the upper part to the leaf towards the tip, inconspicuous ramenta scales along the abaxial midrib; basal pinnae 23-38 × 0.3-0.6 cm, middle pinnae 22-41 × 0.5-1.1 cm, apical pinnae 22.5-29.5 × 0.1-0.3 cm with an asymmetric tip. Inflorescences spicate or spirally branched, with prophyll 6.5-10 × 1.0-1.5 cm; peduncular bract 32-45 cm long, woody, narrow, sulcate, with whitish indument thicker at the base of the bract, inflated portion 19.5-35 × 1.3-2.5 cm, including a 0.8-1.5 cm beak, 1.8-3.1 cm perimeter, 0.8-2 mm thickness; peduncle ca 12.5-18 cm × 3.0-5.0 mm, with white indument; inflorescence axis 12-23 cm long; rachis 0-5.5 cm long; rachillae 1-4(-6), glabrous, 6-15 cm long at the apex, 9.5-18 cm long at the base; flowers arranged in triads or tetrads with two central pistillate flowers, each flanked by a staminate flower, both staminate and pistillate flowers with three sepals and three petals. Staminate flowers 6.4-10.8 × 2.5-4.1 mm at the apex, 8.3-16.8 × 2.6-4.3 mm at the base, those at the apex sessile, those at the base frequently pedicellate, pedicels ca 1 mm long, green to yellow, sepals 0.8-2.0 × 0.5-0.6 mm, glabrous, triangular, no visible nerves, briefly connate at the base, petals 5.5-7.2 × 2.0-2.8 mm at the apex, 8.2-10.2 × 1.5-2.8 mm at the base, with acute tips, nerves indistinct; ovate-triangular, valvate, stamens 3.9-9.5 mm long; anthers 2.7-3.5 mm long; filaments 2.1-6.8 mm long, very briefly connate at the base; pistillode trifid, ca 1.0-1.5 mm. Pistillate flowers elongate-pyramidal, 9.9-10.8 × 4.0-5.8 mm at the apex, 11.8-16.4 × 3.6-7.5 mm at the base, glabrous; sepals 9.9-12.9 × 2.3-2.6 mm, yellow, without visible venation, triangular, imbricate, with scarce hairs at the margin; petals 9.6-10.1 × 1.8-2.4 mm, obscurely nerved and slightly raised on the lower third of the petal, the lower third of margins with multiseriate hairs, imbricate at the base but valvate at the tips, triangular; pistil 5.4-10 × 2.5-4.0 mm, with lepidote indument from the base of the pistil to nearly the base of the stigmas, stigmas 2.7-3.7 mm long, glabrous; staminodial ring ca 0.4-1.2 mm in height, 6-dentate. Fruits ellipsoid, 1.8-2.7 × 1.0-1.6 cm, green tip when mature, tip glabrous, rest of the fruit brown, scaly lepidote tomentum, epicarp less than 0.5 mm thick, mesocarp less than 0.5 mm thick, succulent, and fibrous; endocarp 1.4-1.8 × 1.0-1.3 cm and ca 1 mm thick, trivittate interior. Seeds ellipsoid to nearly globose, endosperm homogeneous. Germination remote tubular.

Distribution.

Syagrus carvalhoi is endemic to the southern part of the Serra do Cabral State Park, municipality of Buenópolis, north-central Minas Gerais state, Brazil (Fig. 4 ).

Habitat and ecology.

The Serra do Cabral is characterised by two well-defined seasons: rainy, with hot and humid summers and mean precipitation of 750 mm, from November to April, and a dry season, with winters occurring from May to October ( Hatschbach et al. 2006). The mean annual temperature is 22°C, but the relief has a significant influence on the temperatures, with higher areas having mild and more humid summers, with mean annual precipitation of 1500 mm and mean temperatures of 20°C ( Hatschbach et al. 2006). The new species grows on quartzitic campos rupestres, on sandy soils of low fertility near rocky outcrops. Among the distinct relief types that compose the Serra do Cabral massif described by Hatschbach et al. (2006), S. carvalhoi occurs in the “plateau” with altitudes between 1000 and 1206 m. These habitats are well represented by species of Poaceae (Fig. 5A ), Velloziaceae (Fig. 5A ), Cyperaceae (Fig. 5B ), Eriocaulaceae (Fig. 5C ), Melastomataceae and Xyridaceae ( Hatschbach et al. 2006; Echternacht et al. 2011; Conceição et al. 2016; Costa et al. 2018). However, the graminoid species dominate in these high landscapes ( Conceição et al. 2016) and the new species goes almost unnoticed due to its grass-like appearance during the rainy season (Fig. 5A ), when most species have fresh greenish or bluish leaves. On the other hand, Syagrus carvalhoi is more easily noticed in the dry season (Fig. 5D ) because it is one of the few species whose leaves do not dry out (and do not lose the bluish colour). Instead, the leaves of S. carvalhoi have a thick epicuticular wax layer covering the lamina and were frequently folded during the dry season - probably by the action of expansion cells on the abaxial surface of the midrib (Fig. 5D-G ). Despite the role of expansion tissue in the unfolding and expansion of the mature lamina ( Tomlinson et al. 2011), the folding of the lamina in palms has been associated with the action of expansion tissue cells combined with the water lost from the hypodermis ( Defaveri et al. 2015; Barbosa et al. 2022). Closing movements of the lamina under dry conditions were also observed for other palms in semi-arid regions and could reduce the loss of water and the incidence of sunlight on the leaf surface ( Oliveira et al. 2016). Regarding the local fauna, the constant presence of snakes under the S. carvalhoi (Fig. 5H ), as well as the signs of rodent predation on its fruits (Fig. 5I ), reinforces the ecological relevance of this palm as a shelter for reptiles and a food source for small mammals in the SC highlands. Different insect species also visit the new species (Fig. 5J-L ). However, the most frequent interaction observed was the remarkable presence of beetle larvae feeding on the seeds (Fig. 5L ). Palm fruits experience greater predation than dispersion ( Henderson 2002; Guimarães and Silva 2012), which, coupled with intense fires and the physical barriers imposed by the relief, probably affects the dispersibility of S. carvalhoi .

Phenology.

The phenology was monitored between December 2019 and November 2022, and the species flowers and bears fruits throughout the year.

Etymology.

The specific epithet carvalhoi is named in honour of Wellington Geraldo Oliveira Carvalho Júnior, a palm enthusiast who discovered this species. Mr Carvalho and his family have provided financial and logistical support to our research in recent years. So, our team’s discoveries were only possible thanks to his support and motivation.

IUCN conservation assessment.

Syagrus carvalhoi is known only within the boundaries of the Serra do Cabral State Park. Near the park, there are small farms where livestock is raised, roads, Pinus sp. and Eucalyptus sp. plantations, and mining gravel extraction ( Hatschbach et al. 2006; Noblick et al. 2014; Costa et al. 2018; Sant’Anna-Santos 2021; Sant’Anna-Santos et al. 2023). Furthermore, according to Hatschbach et al. (2006), the extraction of “sempre-vivas” ( Eriocaulaceae ) also constitutes a severe threat to the native vegetation of the area. Additionally, the Serra do Cabral State Park has been severely affected by fire, and the ever-closer presence of humans. Therefore, due to its restricted area of occupancy (AOO = 12 km2) and the extent of occurrence (EOO = 1.922 km2), and according to the IUCN (2022) categories and criteria, S. carvalhoi should be considered Critically Endangered (CR): B2ab(ii,iii).

Additional specimens examined (paratypes).

BRAZIL - Minas Gerais • Buenópolis, Parque Estadual da Serra do Cabral; 17°56 ’08.85” S, 44°16 ’28.21” W; 1206 m; 6 Jan. 2020; fl.; Sant’Anna-Santos & Firmo 236; MBM • Buenópolis, Parque Estadual da Serra do Cabral ; 17°56 ’08.85” S, 44°16 ’28.21” W; 1206 m; 6 Jan. 2020; fr.; Sant’Anna-Santos & Firmo 237; MBM • Buenópolis, Parque Estadual da Serra do Cabral ; 17°56 ’08.85” S, 44°16 ’28.21” W; 1206 m; 6 Jan. 2020; fr.; Sant’Anna-Santos & Firmo 238; MBM • Buenópolis, Parque Estadual da Serra do Cabral ; 17°56 ’20.50” S, 44°15 ’11.29” W; 1100 m; 7 Jan. 2020; fl.; Sant’Anna-Santos & Firmo 242; MBM • Buenópolis, Parque Estadual da Serra do Cabral ; 17°56 ’20.50” S, 44°15 ’11.29” W; 1100 m; 7 Jan. 2020; fl., fr.; Sant’Anna-Santos & Firmo 244; MBM .

Pinnae anatomy.

Both adaxial and abaxial surfaces of the pinnae are coated by epicuticular wax in the form of hook-shaped filaments (Figs 5G , 6A ). Stomata occur on both surfaces, with guard cells located at the same level as normal epidermal cells (Fig. 6B-C ). The lateral subsidiary cells of the stomata are deeper than the epidermis, with its distal portion reaching the pinnae surface (Fig. 6B, G ). In the cross-section, the hypodermis forms one layer of cells longitudinally elongated to quadrangular shaped on both surfaces (Fig. 6B-E ). The hypodermis below the stomata is interrupted by substomatal chambers (Fig. 6B, G ). The lamina symmetry is isolateral, composed only of palisade parenchyma cells throughout the mesophyll (Fig. 6C-F ). The adaxial tertiary vascular bundles are connected to the hypodermis, while the abaxial tertiary vascular bundles are connected or not to the hypodermis (Fig. 6C, F, H ). The tertiary bundles have no distinguishable protoxylem and metaxylem and are always partially surrounded by a sclerenchymatic sheath (Fig. 6C, F, H ). Secondary and primary vascular bundles are connected to the hypodermis on both surfaces, and the hypodermis is sometimes biseriate above or below these veins (Fig. 6D-E ). The secondary and primary vascular bundles are fully surrounded by a sclerenchymatic sheath (Fig. 6D-E ). The primary vascular bundles have a larger diameter, three to four phloem poles, noticeable protoxylem and metaxylem elements, and a sclerenchymatic sheath extension (Fig. 6E ). Secondary vascular bundles are similar to the primary bundles but with smaller sizes and indistinguishable protoxylem and metaxylem elements (Fig. 6D ). Stegmata with conical to round silica bodies that are somewhat spinulose are frequently associated with the fibres of the vascular bundles (Fig. 6G ). At the margin, tertiary vascular bundles are attached to both surfaces (Fig. 6H ). The raphide-containing idioblasts are commonly found in the centremost layers of the mesophyll (Fig. 6H-I ). The idioblasts are generally empty in thinner and stained sections (Fig. 6H ), but raphides can be noted in thicker and unstained sections (Fig. 6I ). The main vascular system of the midrib consists of two collateral bundles; the larger with more conspicuous xylem vessel elements and phloem (Fig. 6J ). It is surrounded by a fibrous ring and 1-2 accessory bundles on the adaxial surface (Fig. 6J ). Trichomes were observed on the adaxial surface of the midrib (Fig. 6K ). The number of small groups of fibres around the main vascular system might be absent or, when present, in groups of 1 to 3 (Fig. 6J ). The expansion tissue is interrupted and has fibres associated with stegmata (Fig. 6L-M ). Four patterns of vein and fibre arrangement were observed in the leaves of S. carvalhoi . Pattern 1 (Fig. 7A ): on the adaxial surface, there are four nonvascular fibre bundles of various sizes and one tertiary vascular bundle. On the abaxial surface, there are three tertiary vascular bundles (the median one slightly larger) between two primary (or between one primary and one secondary) vascular bundles. Pattern 2 (Fig. 7B ): on the adaxial surface, there are five to six nonvascular fibre bundles of various sizes and one tertiary vascular bundle. On the abaxial surface, there are five tertiary vascular bundles (three large - the median one slightly larger, plus two small) between two primary (or one primary and one secondary) vascular bundles. Pattern 3 (Fig. 7C ): on the adaxial surface, there are three nonvascular fibre bundles of similar size and two tertiary vascular bundles. On the abaxial surface, there are four tertiary vascular bundles (three large - the median is slightly larger, plus one small) between two primary (or between one primary and one secondary) vascular bundles. Pattern 4 (Fig. 7D ): on the adaxial surface, there are two tertiary vascular bundles. On the abaxial surface, there are three tertiary vascular bundles (the median slightly larger) between two primary (or one primary and one secondary) vascular bundles. Pattern 4 did not repeat the arrangement of veins and fibres along the section. So, the number of veins and fibres varies, as shown in Fig. 7C . Table 2 compares the pinnae anatomy of S. carvalhoi and S. cabraliensis .

Key to distinguish between Syagrus carvalhoi and Syagrus cabraliensis

1	Plants with straight leaves; pinnae glaucous on adaxial surface; pinnae with symmetrical tips; 19-26 pairs of pinnae along the rachis; pinnae regularly inserted on the upper part of the rachis; peduncular bract 32-45 cm long; basal and apical rachillae of different length	S. carvalhoi
-	Plants with slightly arched leaves; pinnae glossy on adaxial surface; pinnae with asymmetrical tips; 9-19 pairs of pinnae along the rachis; pinnae inserted at various angles on the upper part of the rachis; peduncular bract 12.2-31 cm long; basal and apical rachillae of similar length	S. cabraliensis

Notes.

Syagrus carvalhoi has a grass-like aspect - typically attributed to dwarf palms with narrow pinnae and slender inflorescences according to Noblick (2017a). Within the genus, a few other dwarf species fit (or nearly fit) the grass-like aspect: Syagrus angustifolia Noblick & Lorenzi, Syagrus campylospatha Becc., Syagrus graminifolia Becc., and Syagrus cabraliensis (Noblick & Lorenzi) B.F. Sant’Anna-Santos ( Noblick 2017a; Sant’Anna-Santos et al. 2023). In addition to its isolation in the Serra do Cabral, S. carvalhoi is easily distinguished from S. angustifolia and S. graminifolia by spirally branched inflorescences - versus unilaterally branched inflorescences in S. angustifolia and S. graminifolia , among other notable morphoanatomical differences ( Noblick 2013b, 2017a, 2017b). Syagrus carvalhoi still resembles S. campylospatha by the spirally branched inflorescences, the colonial habit and the narrow, straight and ascending leaves. However, several morphological characters easily differentiate the two species, for instance, the almost glabrous fruits and the spine-tipped pinnae of S. campylospatha ( Noblick 2017a). Furthermore, the pinnae anatomy of S. campylospatha is unique within the genus ( Noblick 2017a). Finally, S. campylospatha is endemic to Paraguay and Mato Grosso do Sul state in Brazil ( Noblick 2017a), very distant from the distribution of S. carvalhoi . The other grass-like species, S. cabraliensis , shares some rare characters with S. carvalhoi , such as the flowers arranged in tetrads and the stems forking at or below the ground. Thus, based on the rare morphological similarities and the co-occurrence in the SC massif, S. carvalhoi is conceivably closely related to S. cabraliensis . Despite the ca 30 km distance between the populations of S. carvalhoi and S. cabraliensis (Fig. 8A ), the two species are not sympatric. Due to some peculiarities of the relief (Fig. 8A ), the campos rupestres form an archipelago-like system of mountains ( Alves et al. 2014), which promotes isolation favouring speciation. Furthermore, while S. carvalhoi grows in quartzitic campos rupestres in the southern SC (Fig. 8B ), S. cabraliensis occurs on a small ferruginous campo rupestre (Fig. 8C ) on the northern SC ( Noblick et al. 2014; Noblick 2017a; Sant’Anna-Santos et al. 2023). It is not the first case of a species that occurs only in the northern or the southern part of the SC, an area recognised by the presence of narrow endemics ( Noblick et al. 2014; Costa et al. 2018; Guarçoni and Sartori 2020; Sant’Anna-Santos 2021). These endemic dwarf palms of the campos rupestres of the Espinhaço Range revealed a set of rare characters ( Noblick 2009, 2017a; Noblick and Lorenzi 2010; Noblick et al. 2014; Firmo et al. 2021; Sant’Anna-Santos 2021; Sant’Anna-Santos et al. 2023). Regarding the newly discovered dwarf palms for the SC, these endemics possess morphological and anatomical characters that offer new insights for taxonomic, ecological, and evolutionary studies in Arecaceae . For instance, the small group of fibres in the mesophyll of Butia buenopolensis made this species unique within its genus ( Sant’Anna-Santos 2021). From an ecological point of view, the well-developed subterranean stems of these dwarf Arecaceae from the SC may increase their ability to survive intense fires, dry conditions and nutrient-poor soils, as previously stated in the literature ( Glassman 1987; Henderson et al. 1995; Noblick 2017a; Sant’Anna-Santos et al. 2023). Additionally, we showed that the pinnae of S. carvalhoi are covered by a thick epicuticular wax and are frequently folded during the dry season. These characteristics might reduce leaf exposure to sunlight and water loss by transpiration ( Oliveira et al. 2016). The expansion tissue in the midrib of S. carvalhoi is likely linked to the inward folding when subjected to dry conditions, as previously suggested for Allagoptera arenaria (Gomes) Kuntze ( Defaveri et al. 2015) and Allagoptera campestris (Mart.) Kuntze ( Barbosa et al. 2022). The morphological and anatomical differences between these species are shown in Fig. 8 , Tables 1 and 2 , and the key. Morphologically, it is easy to differentiate S. carvalhoi from S. cabraliensis : the former is represented by taller plants, larger and taller clumps (sometimes with colonial habit); bluish leaves that are straight and ascending, pinnae with symmetrical tips; staminate flowers with brief pedicels (Fig. 8B-G ). Anatomically, the pinnae of S. carvalhoi were very useful in differentiating it from S. cabraliensis . For instance, the midrib is a source of characters that did not show variation between the specimens evaluated (Table 2 ). The patterns of veins and the arrangement of fibre bundles were also helpful in differentiating S. carvalhoi from S. cabraliensis (Table 2 ), despite the variation observed along the intermediate region (Fig. 7A-C ) of the former. Noblick (2017b) first cited the variation in pinnae anatomy in the Syagrus genus using the pinnae margin anatomy. For some taxa, Noblick (2017b) carefully used more than one image to represent the pinnae anatomy, as we did here for S. carvalhoi (Fig. 7 ). Thus, a broad and standardised sampling is essential to guarantee the correct characterisation of the studied species ( Noblick 2017b; Noblick and Sant’Anna-Santos 2021). Including S. carvalhoi , 11 species of Syagrus possess variation in pinnae anatomy ( Noblick et al. 2014; Noblick 2017b; Sant’Anna-Santos et al. 2023). However, Syagrus glazioviana Becc. stands out as an extreme regarding such variation, requiring six different images of the same pinnae region (margin) to illustrate the pinnae anatomy of this taxon ( Noblick 2017b). Considering the large area of occurrence of S. glazioviana , it could either indicate a true case of intra-specific variation within a single species or a complex of several closely related unresolved species ( Noblick 2017b). Nevertheless, it is important to emphasise that variation in pinnae anatomy could be expected in narrow endemic species, as shown by Sant’Anna-Santos et al. (2023) for S. cabraliensis and here for S. carvalhoi . However, although such variation is possible, it should not be considered a rule for all taxa. For example, no variation was observed in the pinnae anatomy of Butia buenopolensis , another micro-endemic palm from the southern part of the SC ( Sant’Anna-Santos 2021). Thus, even for narrow endemics, several samples should be collected, and the anatomical data correlated with morphological data, field observations and species distribution before a taxonomic decision. This hitherto unknown species from Serra do Cabral State Park is from the southern part of the Serra do Cabral massif, an area where the Arecaceae flora still needs field efforts in comparison to the northern part of the SC as well as other areas of the Espinhaço Range ( Hatschbach et al. 2006; Reflora 2022; SpeciesLink Network 2022). In the last few years, field efforts of our team have resulted in important advances in the knowledge of Arecaceae from Serra do Cabral, such as the discovery of Butia buenopolensis ( Sant’Anna-Santos 2021), the reassessment of the morphology and anatomy of S. cabraliensis ( Sant’Anna-Santos et al. 2023) and at least one new Syagrus species not yet described ( Firmo et al. 2021). These findings highlight the endemism of the Arecaceae family in the SC with species with rare characters as well as the need for more collection efforts. The restricted distribution of S. carvalhoi suggests that the taxon only grows in that specific habitat and is dependent on its preservation for survival. So, there is an urgent need for additional research to help develop conservation strategies that are more comprehensive and might effectively protect the biodiversity of this overlooked OCBIL.

Figures

Figure 1. Syagrus carvalhoi. A. Straight leaves. B. Spicate inflorescences and infructescences. C. Close-up to a symmetrical pinnae tip. D. Branched inflorescence. E. Staminate flowers at anthesis. F. Tetrad. G. Triad. H. Staminate flower. I. Filaments connate. J. Petal. K. Stamens: ventral view. L. Pistillode. M. Stamens: dorsal view. N. Transversal-section: valvate petals. O. Pistillate flower. P. Sepal keeled. Q. Petal obscurely nerved. R. Petal: trichomes. S. Pistil. T. Infructescence. U. Endocarp pores. A, C-U from Sant'Anna-Santos 377 (UPCB, holotype), spicate inflorescences and infructescences of B added from habitat photographs. Illustration by Gustavo Surlo.

Figure 2. Vegetative morphological aspects of Syagrus carvalhoi. A. Colonial habit near a rock outcrop (black arrowheads). B. Detail of A: straight and ascending leaves. C. Prostrated stem (white arrowhead). D. Roots (white arrowhead). E. Unbranched stem (white arrowhead). F. Forked stem (white arrowhead). G. Acaulescent specimen: without aerial stem (white arrowhead). Photographs by Bruno F. Sant'Anna-Santos.

Figure 3. Reproductive morphological aspects of Syagrus carvalhoi. A. Dried inflorescence: inflorescence peduncle (pe) surrounded by prophyll (pr) and peduncular bract (pb). B. Bifurcate prophyll (white arrowhead). C. Base of a peduncle (pe) and peduncular bract (pb), tomentose (white arrowhead). D. Dorsal surface of the peduncular bract, deeply grooved (white arrowhead). E. Ventral surface of the peduncular bract, deeply grooved (white arrowhead). F. Tetrad after the fall of the staminate flower, bracteoles (br). G. Fruits (fr) with persistent perianth (pp), mostly covered by a brown lepidote indumentum (in) contrasting the green glabrous tip (gt). Photographs by Bruno F. Sant'Anna-Santos.

Figure 4. Distribution maps of Syagrus carvalhoi. A. Minas Gerais State (MG) in Brazil. B. Location of the Serra do Cabral massif (white arrowhead) in Minas Gerais State. C. Location of S. carvalhoi (white dot) in the southern part of the Serra do Cabral State Park.

Figure 5. Habitat and morphoanatomical aspects of Syagrus carvalhoi with ecological implications. A. Specimens of Poaceae (3 black arrowheads) and Velloziaceae (2 white arrowheads) near S. carvalhoi (sc). B. Cyperus sp. C. Paepalanthus sp. D. Pinnae frequently folded during the dry season. E. pinna (pi) manually unfolded exposing the adaxial surface; the red dotted circle shows a diagram of the expansion tissue (et) on a midrib cross-section. F. pinna densely covered by epicuticular wax (ew) compared to an area where the wax was manually removed (re). G. Epicuticular wax, SEM. H. The white circle shows a snake (sn) revealed after removing old leaves. I. Hole (ho) caused by predation of fruits (fr) by rodents. J. Insect (in) on an old pseudopetiole. K. Ant (an) walking on a pinna. L. Larva of a beetle (la) feeding on the endocarp (en). Photographs by Bruno F. Sant'Anna-Santos.

Figure 6. Pinnae anatomy of Syagrus carvalhoi using SEM (A) and LM with cross- (B-H, J-M) and longitudinal (I) sections. A. Adaxial surface: epicuticular waxes (ew) and stomata (st). B. Adaxial surface: guard cells (gc) at the same level of the epidermis (ep); subsidiary cells (sc) at the same level of hypodermis (hy). Cell wall (cw), cuticle (cu). C. Stomata on both surfaces (white arrowheads); palisade parenchyma (pa) throughout the mesophyll; tertiary vascular bundles (t 3) connected to the adaxial hypodermis (grey arrowhead) and not connected to the abaxial hypodermis (black arrowhead). D. Secondary vascular bundles (t 2) connected to hypodermis (black arrowheads) on both surfaces. E. Primary vascular bundles (t 1) connected to the hypodermis (black arrowheads), conspicuous metaxylem (me), protoxylem (white arrowhead) and phloem (ph). F. Adaxial surface: non-vascular fibre bundle (fi) and tertiary vascular bundle (t 3) connected to the adaxial hypodermis (black arrowheads). Palisade parenchyma (pa). G. Silica bodies (white arrowheads) associated with primary vascular bundle (t 1). Palisade parenchyma (pa). H. Tertiary vascular bundles (t 3) and a raphide-containing idioblast (id). I. Idioblast (id) containing raphides (ra). J. Expansion tissue interrupted (surrounded by the dotted white line); fibres in the expansion tissue (white arrowhead); two collateral bundles (white circles); group of fibres (black arrowhead) and accessory bundle (white rectangle). K. Trichome (tr). L. Fibre (black arrowhead) in the expansion tissue (et). M. Silica bodies (white arrowheads) associated with the fibres (black arrowheads) in the expansion tissue (et).

Figure 7. Diagrams of the pinnae variation of vein and fibre arrangement of Syagrus carvalhoi (cross-section of the intermediate region). A. Type 1. B. Type 2. C. Type 3. D. Type 4.

Figure 8. 3 D map of the Serra do Cabral massif (A) and some morphological differences between the grass-like Syagrus carvalhoi (B, D, F) and Syagrus cabraliensis (C, E, G). A. Relief of the SC and the location of S. carvalhoi and S. cabraliensis. B. Bluish, straight and ascending leaves. C. Dark green and slightly arched leaves. D. Symmetrical pinna tip. E. Asymmetrical pinna tip. F. Staminate flower with short pedicel (black arrowhead). G. Staminate flower with long pedicel (black arrowhead). Photographs B-G by Bruno F. Sant'Anna-Santos.