Syagrus aristeae

Sant'Anna-Santos, Bruno Francisco, Carvalho, Luiz Fernando Lima & Soffiatti, Patricia, 2023, A NEW RUPICOLOUS PALM FROM THE CAMPOS RUPESTRES, MINAS GERAIS, BRAZIL, Edinburgh Journal of Botany 80 (1974), pp. 1-15 : 3-11

Syagrus aristeae B.F.Sant’Anna-Santos, sp. nov.

Similar to Syagrus evansiana Noblick but differs by its size (100–165 cm vs 60–100 cm tall); abaxial side of petiole and rachis with tomentum and leaf rachis 94–145 cm

long (vs glabrous and 21–92 cm long); peduncular bract glabrous (vs with indument); inflorescence axis 18–29.5 cm long (vs 4.5–17 cm long); the rachillae of the apex and base of the inflorescence being almost the same siZe (vs different siZes); staminate flowers 10–15.9 mm long and stamens 5.9–9 mm long (vs flowers 8–10 mm long and stamens 3.5–4 mm long); pistillate flowers of the apex and base of the inflorescence being almost the same size (vs different sizes); pistil 5.8–7.7 cm long and glabrous (vs 10–11 cm long with lepidote indument from base to nearly the base of the stigmas); stigmas 3 (vs 3–5), epicarp covered with crackled plates (vs with a thick brown indument). – Type: Brazil, Minas Gerais, Buenópolis, Parque Estadual da Serra Cabral , 17°54′21.00′′S, 44°14′33.30′′W, 1134 m, 14 vii 2022, B. F. Sant’Anna-Santos 388 (holotype DIAM; isotypes IBGE, MBM, UFG, UPCB). Figures 1 , 2 and 3 .

Small, solitary palm, 100–165 cm tall. Stem 10–15 × 3–9 cm, appearing acaulescent or with a short erect or prostrate stem. Leaves 3–6; sheathing leaf base c. 13–23 cm long; pseudopetiole 15–34 cm long; petiole 10–32.5 × 0.8–1.4 cm, 0.3–0.6 cm thick, abaxial side of petiole and rachis with white tomentum; rachis 94–145 cm long; pinnae medium to dark green, discolorous, abaxial surface glaucous, linear, rigid-coriaceous with apex more or less asymmetrical and long tapering, pinnae numbering 38–67 pairs, in clusters of 2 or 3(–4), inserted in divergent planes over the rachis, no ramenta scales or tomentum present where the pinnae are inserted on the rachis, and none along the abaxial midvein of the pinnae; basal pinnae 20–32 × 0.5–1.2 cm, middle pinnae 22–33 × 1.3–3 cm, apical pinnae 7–18 × 0.6–1 cm, one lobe of the asymmetrical tip rounded and the other one rounded or long tapering. Inflorescence erect, spicate or spirally branched, prophyll 7–23 × 1.3–4.8 cm; peduncular bract c. 32–67 cm long, inflated portion 14–31 × 3.3–6.5 cm, including a beak of 1–2 cm, 4–7 cm perimeter, 2.5–3 mm thick, woody, sulcate, exterior glabrous; peduncle 18–42 cm long, 4–9 × 3–6 mm wide, elliptical in cross-section, glabrous; inflorescence axis 18–29.5 cm long; rachis 0–5.5(–10) cm long; rachillae 1–9, 11–21 cm long at the apex, 11–21 cm long at the base, glabrous; staminate flowers 10–12.5 × 3–7.3 mm at apex, 11.2–15.9 × 3–6.6 mm at base, sessile, yellow, sepals 1.3–1.8 × 0.7–1.3 mm at apex, 1.7–3.6 × 1.1–2.6 mm at base, glabrous, no visible nerves, briefly connate at the base, petals 9–11.5 × 2.1–4.4 mm at apex, 9.8–14.8 × 2.8–4.5 mm at base, with acute tips, nerves indistinct, stamens 5.9–9 mm long, anthers 4.4–7.7 mm long; filaments 1.3–3.2 mm long, very briefly connate at the base; pistillode trifid, c. 0.5–1.5 mm long; pistillate flowers elongate-pyramidal, 12.1–16 × 4.4–6.7 mm, glabrous, sepals 11.1–14.6 × 3.9–8.2 mm, yellow, no visible venation, imbricate, petals 7–12 × 1.6–4.7 mm, valvate tips 2/5 to 1/2

the length of the petals, pistil 5.8–7.7 × 2.1–3.9 mm, glabrous, stigmas 3, 2.8–3.4 mm

long, staminodal ring c. 1 mm high, 6-dentate. Fruit nearly globose, 1.7–2.5 × 1.1–1.9 cm, yellowish brown when mature, epicarp covered with stiff appressed brownish plates, epicarp less than 1 mm thick, mesocarp 1–2.5 mm thick, succulent and fibrous; endocarp c.1.3–1.8 × 1.1–1.4 cm, c. 1 mm thick, with 3–5 pores on the basal end; seed to nearly globose, endosperm homogeneous. Germination remote-tubular.

Distribution. Syagrus aristeae is endemic to the Serra do Cabral mountain range, northcentral Minas Gerais state, Brazil ( Figure 4 ).

Habitat and ecology. The species occurs in quartzitic campos rupestres, mainly on rocky outcrops at elevations between 867 and 1238 m (see Figures 2 A–C , 3 A,B ). The campos rupestres are characterised by poor soils and harsh climate conditions (Almada et al., 2016; Fernandes et al., 2020). Recorded with flowers in July and fruits in December, January and July.

Etymology. Named in honor of Professor Aristea Alves Azevedo, one of the most prominent BraZilian botanists and the first woman hired as a professor by the Universidade Federal de Viçosa (UFV) in the 1970s. Recently, she received the Peter Henry Rolfs Medal of Merit in teaching, one of the UFV’s highest honours. She mentored many botanists in plant anatomy, an inarguable source for the taxonomy of Arecaceae . Moreover, her former mentees carry out relevant research in plant conservation in Brazil, including for several botanical families of the campos rupestres of Minas Gerais.

Proposed IUCN conservation category. The extent of occurrence and the area of occupancy of Syagrus aristeae calculated using the online software GeoCAT (Bachman et al., 2011) were 178.741 km 2 and 32 km 2, respectively. Therefore, following the IUCN criteria ( IUCN Standards and Petitions Committee, 2022), this taxon should be classified as Endangered: EN B1b(ii,iii)c(i).

The pinnae of Syagrus aristeae are heavily consumed by locusts (see Figure 2 J,K ). However, the intense fires in the area ( Figure 5 A ) are of more concern for the conservation of the species. Despite the important conservation role of the Serra do Cabral State Park, the area that the Park protects is relatively small (Costa et al., 2018). To illustrate, the populations of Syagrus aristeae are close to the limits of the Park (see Figure 4 ), near the plantations of exotic species such as Pinus sp. , Eucalyptus sp. and Mangifera indica ( Figure 5 B–D ). Some activities with potential negative impact occur in the vicinity of the Serra do Cabral State Park, as previously shown by Costa et al. (2018). Therefore, rare or endemic species from various botanical families are under pressure due to the impact caused by these anthropogenic activities on rocky outcrops (see Figure 5 B ). Recently, electrical poles were installed and there is a noticeable increase in housing construction ( Figure 5 E,F ). Some anthropogenic activities also observed near the Park include gravel extraction ( Figure 5 G ) and the use of ovens for charcoal production ( Figure 5 H ).

Notes. The morphological recognition of the species within the Syagrus glaucescens complex is difficult, even for experienced taxonomists ( Marcato & Pirani, 2001). In the past, Syagrus duartei and S. glaucescens were considered the same taxon by Marcato & Pirani (2001). However, these authors did not consider the differences in leaf anatomy shown by Glassman (1972, 1987). Recently, Noblick (2013b, 2017b) showed that Syagrus evansiana , the third species included in the complex, also possess a distinct leaf anatomy pattern ( Noblick, 2009, 2017a, 2017b; Firmo et al., 2021).

Plant size is an important feature in distinguishing between species in the Syagrus glaucescens complex ( Glassman, 1987; Noblick, 2009, 2017a; Firmo et al., 2021). For the differentiation of Syagrus duartei and S. glaucescens , the larger peduncular bracts, larger inflorescences, and larger globose fruit of S. duartei are reliable characters ( Noblick, 2017a). On the other hand, Syagrus evansiana has unique distinguishing characteristics, such as its smaller siZe, the two types of inflorescences, and the variable number of endocarp pores ( Noblick, 2009, 2017a).

Geographically, the species of the Syagrus glaucescens complex possess almost separate distributions ( Marcato & Pirani, 2001; Noblick, 2009, 2017a; Firmo et al., 2021). Syagrus duartei is endemic to Serra do Cipó, whereas S. glaucescens is more abundant in the region of Diamantina, although some latter specimens could be found near the distribution limits of S. duartei ( Noblick, 2017a) . Syagrus evansiana occurs further north than S. duartei and S. glaucescens ( Noblick, 2017a) , whereas S. aristeae is endemic to the Serra do Cabral, a massif that shows a remarkable degree of endemism and holds rare species from several botanical families, including recent newly described species in Arecaceae ( Noblick et al., 2014; Costa et al., 2018; Firmo et al., 2021; Sant’Anna-Santos, 2021; Sant’Anna-Santos et al., 2023a, 2023b).

The specimen (Marcato et al. 313) identified as the new species in this paper was the first (but erroneous) record of Syagrus glaucescens from the Serra do Cabral (SpeciesLink Network, 2022). However, at that time, some Brazilian taxonomists considered Syagrus duartei and S. glaucescens to be conspecific ( Marcato & Pirani, 2001) and S. evansiana had not yet been described, which explains the mistake. Later, Syagrus evansiana was described as a new species from the northern portion of Minas Gerais ( Noblick, 2009) and added to the S. glaucescens complex as the third taxon. Recently, the northern portion of the Serra do Cabral was included as the occurrence area of Syagrus evansiana ( Noblick, 2017a) , which led us to look for it in that region in our studies on the Arecaceae flora in the Serra do Cabral.

An unusual Syagrus population was found on the Serra do Cabral with younger individuals (already in reproductive phase) resembling S. evansiana , and mature specimens appearing to be larger (resembling S. duartei ). This led them to be considered “confusing intermediates” belonging to the Syagrus glaucescens complex ( Noblick, 2017a). However, the Serra do Cabral is isolated from the area of Espinhaço Range where Syagrus evansiana , S. duartei and these “confusing intermediates” are commonly found ( Noblick, 2017a; Firmo et al., 2021). Thus, in the following years, we focused on searching for more mature specimens in the reproductive stage to confirm this unusual population of the Serra do Cabral as a new endemic species. As a result, we found specimens with two types of inflorescences (unbranched and branched), which resemble those of Syagrus evansiana and not S. duartei or S. glaucescens ( Noblick, 2009, 2017a; Firmo et al., 2021). Additionally, as previously discussed by Firmo et al. (2021), we observed that the number of endocarp pores varied between three and five, a character found in both the new Serra do Cabral species and Syagrus evansiana . A reassessment of the leaf anatomy of the entire complex highlighted that these individuals were anatomically distinct from the other species of the complex (see Firmo et al., 2021).

Both Syagrus aristeae and S. evansiana occur in campos rupestres of the Espinhaço Range in Minas Gerais, but S. aristeae is commonly found growing on quartzitic rocky outcrops whereas S. evansiana is not ( Noblick, 2009, 2017a). Prostrate stems are common in Syagrus aristeae but not in S. evansiana ( Firmo et al., 2021) , and there are six stamens (sometimes eight) in S. aristeae whereas S. evansiana has only six stamens. Other differences are described in the diagnosis and the identification key. The leaf anatomy differences between Syagrua aristeae and S. evansiana are given in Firmo et al. (2021).

Additional specimens examined. BRAZIL. Minas Gerais: Joaquim Felício, Arredores da zona urbana, Balneario Veredas , 17°45′28.00′′S, 44°10′42.00′′W, alt. 705 m, 19 v 2001, A. C. Marcato et al. 313 ( SPF) ; Joaquim Felício, Pedra Alta , 17°42′2.78′′S, 44°12′48.12′′W, alt. 1138 m, 8 xii 2015, B. F. Sant’Anna-Santos & I. F. P. Azevedo 40, 41, 42, 43 ( MCMG, UPCB) ; Buenópolis, Parque Estadual da Serra do Cabral , 17°54′44.28′′S, 44°12′42.06′′W, alt. 867 m, 16 xii 2019, B. F. Sant’Anna-Santos & D. H. T. Firmo 199 ( UPCB) ; Buenópolis, Parque Estadual da Serra do Cabral , 17°54′33.84′′S, 44°14′19.14′′W, alt. 1109 m, 16 xii 2019, B. F. Sant’Anna-Santos & D. H. T. Firmo 200 ( UPCB) ; Joaquim Felício, Parque Estadual da Serra do Cabral , 17°45′51.72′′S, 44°16′31.50′′W, alt. 1238 m, 17 xii 2019, B. F. Sant’Anna-Santos & D. H. T. Firmo 226 ( UPCB) ; Joaquim Felício, Parque Estadual da Serra do Cabral , 17°42′2.46′′S, 44°12′47.64′′W, alt. 1141 m, 8 i 2020, B. F. Sant’Anna-Santos & D. H. T. Firmo 245 ( UPCB) ; Joaquim Felício, Parque Estadual da Serra do Cabral , 17°42′1.56′′S, 44°12′46.56′′W, alt. 1138 m, 8 i 2020, B. F. Sant’Anna-Santos & D. H. T. Firmo 246 ( UPCB) ; Buenópolis, Parque Estadual da Serra do Cabral , 17°55′13.56′′S, 44°15′38.34′′W, alt. 1135 m, 9 i 2020, B. F. Sant’Anna-Santos & D. H. T. Firmo 253 ( UPCB) ; Buenópolis, Parque Estadual da Serra do Cabral , 17°54′20.88′′S, 44°14′30.12′′W, alt. 1115 m, 7 i 2021, B. F. Sant’Anna-Santos 319 ( UPCB) .

Figures

Figure 1. Syagrus aristeae B.F.Sant’Anna-Santos, sp. nov. A, Solitary habit; B, asymmetrical tip; C, unbranched inflorescence; D, branched inflorescence. E–J, staminate flower: E, staminate flower, opened; F, detail of calyx; G and H, petals; I, dorsal view of stamens; J, ventral view of stamens and pistillode. K–S, pistillate flower: K, pistillate flower (front view); L–N, sepals; O–Q, petals; R, pistil; S, staminodal ring. T, Stigma; U, three endocarp pores; V, four endocarp pores. Drawn from the holotype, Sant’Anna-Santos 388 (DIAM), by G. Surlo.

Figure 2. Syagrus aristeae B.F.Sant’Anna-Santos, sp. nov. A, Landscape photograph of the type locality in the Serra do Cabral State Park: individuals (white rectangles) growing in the rocky outcrops (Ro); B, specimen (black arrow) growing in the rocky outcrop (Ro); C, specimen (black arrow) growing on the sandy soils near rocky outcrops (Ro); D, pinnae irregularly arranged in the leaf rachis; E, dark-green adaxial (Ad) and glaucous abaxial (Ab) surfaces of the pinnae; F, the asymmetrical tip (white arrow); G, the long tapering tip (white arrow); H, abaxial side of the leaf rachis with white tomentum (To); I, leaf sheath with fibrous margins; J, pinnae consumed (white arrow) by locusts: abaxial surface (Ab); H, pinnae consumed (white arrow) by locusts: adaxial surface (Ad). Photographs: B. F. Sant’Anna-Santos.

Figure 3. Syagrus aristeae B.F.Sant’Anna-Santos, sp. nov. A, Habitat photograph of the type locality in the Serra do Cabral State Park: individual flowering (white circle); B, branched inflorescence; C, detail of branched inflorescence: floral visitor on the peduncular bract (PB); D, rachillae with pre-anthesis flowers stored in ethyl alcohol: triads (a central pistillate flower flanked by two staminate flowers) on the lower portion of the rachilla (black line) and isolated staminate flower occupying the upper half of the rachilla (blue line); E, deeply grooved peduncular bract (PB); F, prophyll (Pr); G, unbranched inflorescence; H, fruits (Fr): epicarp covered with crackled plates. Photographs: B. F. Sant’Anna-Santos.

Figure 4. Distribution of Syagrus aristeae B.F.Sant’Anna-Santos, sp. nov. in the Serra do Cabral State Park, Minas Gerais (MG).

Figure 5. Examples of diverse threats in the vicinity of the Serra do Cabral State Park: A, large-scale fire; B, plantation of Pinus sp. (black arrow) – the white circle shows a rare species of Cactaceae on a small rocky outcrop (Ro); C, plantation of Eucalyptus sp. (white arrow) near a rocky outcrop (Ro); D, plantation of Mangifera indica near a rocky outcrop (Ro); E, electrical poles recently installed; F, houses; G, gravel mining; H, charcoal plant. Photographs: B. F. Sant’Anna-Santos.