Pseudobombax furadense Gianasi & Santos, 2022

Gianasi, Fernanda Moreira & Santos, Rubens Manoel Dos, 2022, Pseudobombax furadense (Bombacoideae, Malvaceae), a new species from the Caatingas Domain, Brazil, Phytotaxa 544 (1), pp. 71-80 : 72-77

Pseudobombax furadense Gianasi & Santos , sp. nov. ( Figures 2 , 3 & 4 )

Type: — BRAZIL. Minas Gerais: Distrito de Montalvânia, Furados, acesso pela estrada de terra que liga Montalvânia ao Distrito de Capitania , 14°23’59”S 44°24’01”W, 526m, 29 January 2020, F. M . Gianasi , R. M . Santos , F . Oliveira and L. C. A. P Silva 03 (holotype: ESAL32614 , isotype: HUFSJ) .

Diagnosis: — Pseudobombax furadense is morphologically similar to Pseudobombax simplicifolium , but differs by the obovate, elliptic, depressed obovate or rarely orbicular leaflets (vs. ovate, ovate-elliptic, widely elliptic or ovate-lanceolate in P. simplicifolium ), the presence of branched trichomes on terminal branches, leaf primordia, petioles, adaxial and abaxial surfaces of leaflets, pedicel, bracteoles, and the outer surface of the calyx (vs. glabrous, glabrescent to subglabrescent with peltate microtrichomes), lepidote ovary (vs. glabrous), and subglobose, ovoid to oblong, spotted seeds, clear brown with gray spots (vs. pyriform to subglobose, unspotted, and clear brown without gray spots).

Description: —Tree 5–9 m; stem with grayish suberized bark and greenish longitudinal bands; branches slender, opaque with whitish wax coating, apex pubescent with branched trichomes; brachyblasts present. Stipules 4.15–6.7 × 0.84–3.14 mm, persistent, filiform to triangular, concave, acuminate, densely pilose with branched trichomes in young stipules, sparsely pilose and with whitish wax coating in senescent stipules. Leaves 1 – 3(– 5)–foliolate, often united at the branch apex in brachyblasts; leaf primordia densely pilose with branched trichomes adaxially and abaxially; petiole 0.5–4.6 cm long, densely pilose with branched trichomes, slightly thickened at the base and apex, with glands along its length; petiolule absent; leaflets (3 –)4 – 6.5(– 8) × (2.4 –) 3.5 – 5.5 cm, obovate to widely depressed obovate, rarely orbicular, chartaceous, base obtuse, cuneate to rounded, apex obtuse, retuse to rounded, margin entire; adaxial surface pilose, less often sparsely pilose with branched trichomes; abaxial surface pilose to densely pilose with branched trichomes; midrib adaxially pilose to densely pilose with branched trichomes, abaxially prominent, densely pilose with branched trichomes. Flower buds narrowly oblong; flowers terminal or subterminal, solitary or in groups of 2 – 4; pedicel 1.5 – 2.5 cm long, longitudinally striated, pilose to densely pilose with branched trichomes; bracteoles 2 – 4, ca. 4 × 2 mm, triangular, slightly concave, margin denticulate or not, adaxially glabrescent, abaxially pilose with branched trichomes; receptacle ca. 1.5 mm, glabrescent to densely pilose with branched trichomes, 1 whorl of ca. 6 glands; calyx 10 – 12 × 10 – 16 mm, cupuliform, apex truncate, inconspicuously 5–apiculate at the apex (apicle densely pilose), outer surface sparsely pilose to pilose with branched trichomes and peltate microtrichomes, occasionally with whitish wax coating in immature buds, internally sericeous on the upper 1/5 with simple and bifid trichomes, incanous on the lower 4/5, cream in herborized plants; petals 10–14 × 0.8–1 cm, linear, apex acute to obtuse, base glabrous, abaxially with two longitudinal strips golden to brown and cream, covered with rigid branched trichomes, sericeous near the base, adaxially cream, covered by a strip of branched trichomes and a strip of simple and bifid trichomes; stamens ca. 150, staminal tube 8–12 × 1.4 – 2 mm, phalanges absent, glabrous, filaments free for 85 – 100 mm, anthers 1.5–2.8 mm long, glabrous; ovary ca. 7 × 1.5 mm, inconspicuously sulcate or not, lepidote, narrowly oblong, apex acute, style 10 – 12.5 cm long, glabrous. Capsule 8 – 17.5 × 2 cm, narrowly oblong, not angulate, often apiculate (ca. 4 mm), valves woody, glabrous, clear brow; kapok cream to clear brown; seeds 4.4 – 5 × 3.15 – 3.9 mm, subglobose to ovoid, spotted, clear brown, spots gray, hilum not prominent, slightly darker or not.

Distribution, habitat, and ecology: — Pseudobombax furadense occurs in northern Minas Gerais state and southern-central Bahia state in Brazil ( Fig. 5 ), and is probably endemic to the Furados microhabitats of the Caatingas Domain ( Fig. 1 ). The individuals of the sampled population are clumped and mostly distributed on shallow soils with exposed limestone slabs. The Furados is a resource-limited environment, characterized by limestone slabs with flat and regular surfaces and shallow soils deposited at specific points where water accumulates during the rainy season due to the impermeable nature of the underlying rock ( Paula et al. 2018). Previous studies have revealed the unique plant community structure and composition contained in the Furados ( Gianasi et al. 2020, Paula et al. 2018).

Phenology: — Pseudobombax furadense have deciduous foliage in dry season. Seed dispersal and leaves were observed in February; flowers and fruits at different stages of maturation were observed in August.

Etymology: —The specific epithet refers to its microhabitat of occurrence, characterized by limestone slabs, commonly known as Furados.

Preliminary conservation status: — Pseudobombax furadensis occurs only in northern of Minas Gerais and south of Bahia, in Brazil, and is probably endemic to Furados in Caatinga domain. Only 6 populations are known and the sampled population presented clustered individuals, mostly distributed on shallow soils with exposed limestone slabs. Most populations are under strong pressure from agropastoral activities and the extent of occurrence (EOO) estimated is less than a 20.000 km ² (19,462.682 km ²). Pseudobombax furadense was assessed as Vulnerable (VU) according to the IUCN criteria B1ab(iii).

Notes: — Pseudobombax furadense is characterized the presence of brachyblasts; leaves 1–3(–5)–foliolate covered with branched trichomes, leaflets obovate to widely depressed obovate and abaxial surface pilose to densely pilose with branched trichomes; flowers with branched trichomes in the pedicel, bracteole, and calyx; phalanges absent and seeds clear brown with gray spots. P. furadense is morphologically similar to P. simplicifolium for often presenting leaves often unifoliolate united at the apex in brachyblasts, stipules persistent, flowers terminal or subterminal, phalanges absent and capsule narrowly oblong, not angulate and often apiculate. But the new species differs by the number of leaflets [1–3(–5)–foliolate in P. furadense vs. 1–3–foliolate in P. simplicifolium ]; the relatively longer petiole (0.5–4.6 cm long vs. 0.4–1.5 cm long); the leaflets obovate to widely depressed obovate, rarely orbicular (vs. ovate, ovateelliptic, widely elliptic or ovate-lanceolate); the presence of branched trichomes on terminal branches, leaf primordia, petioles, adaxial and abaxial surfaces of leaflets, pedicel, bracteoles, and the outer surface of the calyx (vs. glabrous, glabrescent to subglabrescent with peltate microtrichomes); the petals relatively narrower (0.8–1.0 cm wide vs. 0.8–2.3 cm wide); the ovary lepidote (vs. glabrous in P. simplicifolium ); and the seeds subglobose to ovoid, spotted, clear brown, gray spots (vs. pyriform to subglobose, unspotted and clear brown). Leaflet indumentum is a character of great taxonomic value to separate the Pseudobombax species present in the Caatingas Domain ( Carvalho-sobrinho 2010) ( Table 1 ), with the majority of the species displaying glabrous or glabrescent leaves, except for the peltate microtrichomes, including P. simplicifolium . The presence of branched trichomes in the petioles and leaflets of P. furadense is a trait that allows it to be easily distinguished from P. simplicifolium in vegetative specimens.

Additional specimens examined (paratypes): — BRAZIL. Bahia: Guanambi, BR-030 chegando na cidade, Caatinga, 14º13’37”S 42º54’45”W, 17 March 2011, Carvalho-Sobrinho, J. G . 2996 ( HUEFS 171835 ); Serra do Ramalho , depois de Alagoinha, Caatinga sobre afloramentos calcários, 13°46’59”S 43°58’04”W, 570m, 16 March 2011, Carvalho-Sobrinho, J. G . 2990 ( HUEFS 171830 ); localidade de Porto Novo, 8km da vila em direção a Santana, Caatinga sobre afloramentos calcários, 12º 58’ 59”S 44º 03’ 04”W, 15 March 2011, Carvalho-Sobrinho, J. G . 2986 ( HUEFS 171826 ) . Minas Gerais: Distrito de Montalvânia , Furados, acesso pela estrada de terra que liga Montalvânia ao Distrito de Capitania, 14°23’59”S 44°24’01”W, 526m, 29 January 2020, Gianasi, F. M.; Santos, R. M.; Oliveira, F.; Silva, L. C. A. P01 ( ESAL 32612 ); 14°23’59”S 44°24’01”W, 526m, 29 January 2020, Gianasi, F. M.; Santos, R. M.; Oliveira, F.; Silva, L. C. A. P.02 ( ESAL 32613 ); 14°23’59”S 44°24’01”W, 526m, 29 January 2020, Gianasi, F. M.; Santos, R. M.; Oliveira, F.; Silva, L. C. A P. 04 ( ESAL 32615 ); 14°23’59”S 44°24’01”W, 526m, 29 January 2020, Gianasi, F. M.; Santos, R. M.; Oliveira, F.; Silva, L. C. A. P05 ( ESAL 32616 ); 14°23’59”S 44°24’01”W, 526m, 29 January 2020, Gianasi, F. M.; Santos, R. M.; Oliveira, F.; Silva, L. C. A. P. 06 ( ESAL 32617 ); 14°23’59”S 44°24’01”W, 526m, 29 January 2020, Gianasi, F. M.; Santos, R. M.; Oliveira, F.; Silva, L. C. A. P. 07 ( ESAL 32618 ); 14°23’59”S 44°24’01”W, 526m, 29 January 2020, Gianasi, F. M.; Santos, R. M.; Oliveira, F.; Silva, L. C. A. P.08 ( ESAL 32619 ); 14°23’59”S 44°24’01”W, 526m, 29 January 2020, Gianasi, F. M.; Santos, R. M.; Oliveira, F.; Silva, L. C. A. P. 09 ( ESAL 32620 ); 14°23’59”S 44°24’01”W, 526m, 29 January 2020, Gianasi, F. M.; Santos, R. M.; Oliveira, F.; Silva, L. C. A. P10 ( ESAL 32621 ); 14°23’59”S 44°24’01”W, 526m, 29 January 2020, Gianasi, F. M.; Santos, R. M.; Oliveira, F.; Silva, L. C. A. P.11 ( ESAL 32622 ); 14°23’59”S 44°24’01”W, 526m, 29 January 2020, Gianasi, F. M.; Santos, R. M.; Oliveira, F.; Silva, L. C. A. P.12 ( ESAL 32623 ); 14°23’59”S 44°24’01”W, 526m, 09 August 2019, Gianasi, F. M., Santos, R. M.; Aguiar-Campos, N.; Oliveira, F.; Santos, P. F. R1 ( ESAL 32624 ); 14°23’59”S 44°24’01”W, 526m, 09 August 2019, Gianasi, F. M., Santos, R. M.; Aguiar-Campos, N.; Oliveira, F.; Santos, P. F., R4 , ( ESAL 32625 ); 14°23’59”S 44°24’01”W, 526m, 09 August 2019, Gianasi, F. M., Santos, R. M.; Aguiar-Campos, N.; Oliveira, F.; Santos, P. F. R3 ( ESAL 32627 ); 14°23’59”S 44°24’01”W, 526m, 09 August 2019, Gianasi, F. M., Santos, R. M.; Aguiar-Campos, N.; Oliveira, F.; Santos, P. F. R2 ( ESAL 32626 ); 14°23’59”S 44°24’01”W, 526m, 09 August 2019, Gianasi, F. M., Santos, R. M.; Aguiar-Campos, N.; Oliveira, F.; Santos, P. F. R3 ( ESAL 32627 ); 14°23’59”S 44°24’01”W, 526m, 09 August 2019, Gianasi, F. M., Santos, R. M.; Aguiar-Campos, N.; Oliveira, F.; Santos, P. F. R5 ( ESAL 32628 ); Itacarambi, Parque Nacional Cavernas do Peruaçu, Floresta Estacional Decidual com dossel a ca. 20 m altura e afloramentos calcários, 15°01’42”S 44°15’12”W, 07 March 2015, Queiroz, L. P. 16123 ( HUEFS 214937 ); Matias Cardoso, Próximo a Lajedão, terra do Sr. Raimundo Gato, 14°53’15”S 43°45’28”W, 497m, 13 March 2016, Pezzini, F. F. 113 ( HUEFS 223045 ); 14°53’10”S 43°45’16”W, 497m, 13 March 2016, Pezzini, F. F. 110 ( HUEFS 223042 ); 14°53’15”S 43°45’18”W, 497m, 29 April 2016, Pezzini, F. F. 201 ( HUEFS 223126 ) .

Figures

FIGURE 1. Furados A. Aerial view of the Furados microhabitat in Montalvânia (Minas Gerais state, Brazil). Circled in red and surrounded by dense Arboreal Caatinga vegetation feature the exposed limestone. B. A closer view of the dense Arboreal Caatinga vegetation during the wet season. C. A closer view of the limestone slabs; note that the trees inhabiting this environment are scarce.

FIGURE 2. Pseudobombax furadense Gianasi & Santos, sp. nov.: A. Brachyblasts, leaflets with branched trichomes, and 5–valvate capsule. B. Adaxial surface. C. Abaxial surfaces. D. Seed.

FIGURE 3. Pseudobombax furadense Gianasi & Santos, sp. nov.: A. Flowering branch. B. Ovary.C. Detailed view of the calyx with outer surface sparsely pilose. D. Stamens and staminal tube.

FIGURE 4. Pseudobombax furadense Gianasi & Santos, sp. nov.: A. Flowers terminal or subterminal, solitary or in groups of 2–4, receptacle with 1 whorl of ca. 6 glands; calyx cupuliform, outer surface sparsely pilose to pilose with branched trichomes and stamens cream. B. Leaflets obovate to widely depressed obovate with adaxial and abaxial surfaces pilose to densely pilose with branched trichomes and fruit with valves woody, glabrous, kapok clear brown; scale bar = 1cm. C. Leaves united at the apex in brachyblasts. Detailed view: D. Branched trichomes in the adaxial surface. E. Branched trichomes in the abaxial surface. F. Ovary lepidote. G. Seed clear brown, spots gray. Scale bar = 1mm.

FIGURE 5. Distribution map of Pseudobombax species occurring in the Caatingas Domain. Endemic species of the Caatingas Domain: P. calcicola, P. parvifolium, P. simplicifolium and Pseudobombax furadense Gianasi & Santos, sp. nov. P marginatum is widely distributed (occurring in the Caatingas, Cerrado, and Pantanal), but the map only shows its occurrence points in the Caatingas.