Eriotheca luzensis Yoshikawa & M.C. Duarte

Yoshikawa, Vania N., Marinho, Rafaela C., Mendes-Rodrigues, Clesnan, Oliveira, Paulo E. A. M. & Duarte, Marília C., 2024, A new polyembryonic species of Eriotheca (Malvaceae, Bombacoideae) from the Brazilian Cerrado, Phytotaxa 652 (2), pp. 115-123 : 116-122

Eriotheca luzensis Yoshikawa & M.C. Duarte , sp. nov. ( Figures 1 , 2 , 3 & 4 )

TYPE:— BRAZIL. Minas Gerais: Luz, Posto Barril , beira da rodovia, 19º46’58.6’’S, 45º33’51.5’’W, 15 August 2013, C. M. Rodrigues & R. C. Marinho 82 (holotype HUFU 68021 [barcode 15077]!; isotype HUMC 6657 !) .

Diagnosis: — Eriotheca luzensis can be confused with E. pubescens by the abundant indumentum in the leaflets, pedicel and calyx, and by the strong coriaceous leaflets, but they differ by the pubescent indumentum, composed by yellowish stellate trichomes grouped at the apex of the calyx vs. velutinous indumentum, composed by golden stellate trichomes, distributed along the calyx; and by the free part of stamens (130 vs. 200).

Description: — Trees 8–10 m high. Branches 0.5–1 cm diam., brown, striate, striae light brown, glabrescent, with simple, sparse, hyaline trichomes. Stipules 0.1–0.6 × 0.1–0.4 cm, deltoid, with simple, yellow trichomes grouped at the apex, rarely ciliate. Petioles (1.6)4.5–9(–15) × 0.1–0.4 cm, with two linear nectaries at the base, glabrescent, yellow to hyaline, rarely black, trichomes simple and stellate, 2–4-radiate. Leaves alternate, palmately compound, with three leaflets. Petiolules sessile or ca. 0.3 cm long. Leaflet blades 3.7–16.5 × 1.8–7 cm, obovate to oblong-obovate, discolored, green in the adaxial surface, light green in the abaxial surface, chartaceous to slightly coriaceous, bases cuneate or decurrent, margin entire, plane, rarely revolute, apices emarginate; adaxially glabrous or glabrescent, with stellate, 2–5-radiate, yellow or hyaline trichomes, rarely lepidote, with appressed scales, ferruginous, with regular outline, abaxially glabrescent, with simple and stellate, 2–5-radiate trichomes, yellow trichomes and lepidote, with non-appressed scales, ferruginous, rarely associated with brown scales, with regular outline, more present in young leaflets; veins brochidodromous, presence of a nectary in the apical third of the primary vein in the abaxial surface, 8– 13 pairs of secondary veins. Cymes 1–5-flowered, born in the axil of leaves. Flowers 2.5–3.5 cm long; pedicels 1–4.3 cm long, lepidote, with appressed, ferruginous scales of regular outline, rarely with stellate, yellow trichomes; flower buds 0.3–0.8 × 0.3–0.6 cm, globose to depressed-globose, rarely ovoid; bracts 0.1–0.2 × 0.1 cm, caducous, deltoid, indumentum the same as the pedicel, rarely grouped at the apex; receptacle without nectaries; calyx 0.5–0.8 × 0.5–1.1 cm, campanulate, cupuliform in the flower bud, ferruginous, apices truncate, rarely irregularly apiculate, externally lepidote at the base, indumentum the same as the pedicel, apices associated with pubescent trichomes, stellate, 5- radiate, yellow, internally velutinous, trichomes simple, hyaline; petals 2–3 × 0.5–0.8 cm, obovate, apices rounded, bases truncate, dorsal and ventral indumentum velutinous, trichomes simple, yellow; staminal tube 0.3–0.6 × 0.2 cm, cream, constricted in the middle portion, glabrous, rarely glabrescent, with simple and stellate, hyaline trichomes; phalanges absent; free part of stamens 130, 0.6–1.3 cm long, cream, glabrous; anthers 0.05–0.1 cm long, yellow, glabrous; styles ca. 1.3 cm long, cream, glabrous; stigmas ca. 0.1 cm long, capitate, cream, glabrous; ovaries ca. 0.1 × 0.1 cm, cream, 5-costate, ovoid, glabrous. Fruits 6.5–6.8 × 4–4.2 cm, obovoid. Seeds ca. 0.6–0.7 × 0.7 cm, striate.

Notes: — Eriotheca luzensis can be confused with E. estevesiae and E. pubescens by the abundant indumentum in the leaves and floral parts. For a morphological comparison of the new species with these two and other species of Eriotheca from state of Minas Gerais, see Table 1 .

In comparison to E. estevesiae , E. luzensis also has a pubescent indumentum and the brown to ferruginous calyx ( Figs. 1 , 2D , 3B ). The new species can be differentiated from E. estevesiae by the obovate to oblong-obovate (vs. linear) leaflets, and the flowers 2.5–3 cm long. (vs. up to ca. 2 cm long).

Eriotheca luzensis can be differentiated from E. pubescens by pubescent and yellow (vs. velutinous and golden) indumentum, longer pedicels (1–4.3 cm long vs. up to 0.6 cm), trichomes grouped at the apex of the calyx (vs. equally distributed in the calyx), and 130 (vs. 200) stamens, distributed only in the state of Minas Gerais (vs. widely distributed in Cerrado) ( Figs. 1 , 2D, E , 3A–D and 4 ), by 11–12 (vs. 15–16) seeds per fruit, and 121.75 mg (vs. 155.38–159.79 mg) seed mass.

Regarding polyembryony, it was also described in other species of the genus ( Mendes-Rodrigues et al. 2019) and in other species from Cerrado ( Salomão & Allem 2001). This embryonic pattern is usually associated with apomixis and polyploidy in angiosperms ( Hörandl 2022), and in others Eriotheca species ( Mendes-Rodrigues et al. 2019; Marinho et al. 2021).

Distribution, habitat and ecology: —The new species is endemic to the state of Minas Gerais, Brazil, and its populations were found in cerradão phytophysiognomy ( Fig. 4 ). The Luz population was composed by 8 individuals.

Preliminary conservation status: — Eriotheca luzensis has an Extent of Occurrence of 18,000 km 2 and it is known from only five localities; two of its populations occur in protected areas (Serra do Calixto and Parque Estadual do Rio Preto) ( Fig. 4 ), while the other three occur in anthropized areas (such as Posto Barril, Luz municipality), being subjected to declines in habitat quality and extension due to deforestation. For these reasons, E. luzensis is here classified as Vulnerable (VU) following criteria B1ab (i, iii, iv).

Etymology: —The epithet of E. luzensis refers to the type locality, in the municipality of Luz, Minas Gerais.

Additional specimens examined: — BRAZIL. Minas Gerais: Bocaiúva, Estrada Cordeiro-Terra Branca , July 1993, L. V. Costa s.n. ( BHCB27610 !). Francisco Sá, na estrada para Grão Mogol, 22 July 1985, G. Martinelli et al. 11245 ( BHCB!, NYBG!, RB!) ; ibid. 11km de Francisco Sá, Serra do Calixto, 26 November 1981, R. M. Harley et al. CFCR 6168 ( SPF!). Luz, Posto Barril, BR262 , 19º46’S, 45º33’W, 690 m elev., 20 September 2011, C. M. Rodrigues 80 ( HUFU!, HUMC!). Santana do Pirapama, Inhames – Caminho da captação da Fazenda Toucan Cipó, 20 September 2011, C. M. Rodrigues 79 ( HUFU!, HUMC!). São Gonçalo do Rio Preto , Parque Estadual do Rio Preto. Cerrado próximo ao Córrego das Boleiras, s.d., F. N. Costa & L. G. Lessa 887 ( SPF!) ; ibid., 18 July 2001, Q. S. Garcia & F. Vieira s.n. ( BHCB61843 !). Três Marias, 18º12’39.1’’S, 45º50’19’’W, 05 July 2014, C. M. Rodrigues & R. C. Marinho 100 ( HUFU!). ibid. 18º08’57.7’’S, 45º45’24.4’’W, 07 October 2013, C. M. Rodrigues & R. C. Marinho 86 ( HUFU!, HUMC!) .

Figures

FIGURE 1. Paratype of Eriotheca luzensis. C.M. Rodrigues 82 (HUMC).

FIGURE 2. Morphological features of Eriotheca luzensis. (A): adaxial surface, showing sparse and stellate trichomes, (B) abaxial surface, showing scales, and sparse stellate trichomes, (C) gynoecium, (D) calyx on flower bud, (E) staminal tube and stamens, (F) apical stipule. C.M. Rodrigues 80 (HUMC).

FIGURE 3. Field images of Eriotheca luzensisfrom the type locality.(A): flowering specimen,(B): branches anddetail of the inflorescence, (C): flowers, (D): fruits and kapok.

FIGURE 4. Geographical distribution of Eriotheca luzensis in the state of Minas Gerais.