Magnolia irwiniana (Lozano) Govaerts, World Checkl. and Bibliogr. Magnoliaceae: 71. 1996.

Barbosa, Juliana Cruz Jardim, Caruzo, Maria Beatriz Rossi, Simoes, Ana Rita G. & Samain, Marie-Stephanie, 2024, Taxonomic revision of the native Magnolia (Magnoliaceae) species of Brazil, PhytoKeys 238, pp. 33-64 : 33

Magnolia irwiniana (Lozano) Govaerts, World Checkl. and Bibliogr. Magnoliaceae: 71. 1996.

Figs 6 , 8

Talauma irwiniana ≡ Talauma irwiniana Lozano, Rev. Acad. Colomb. Ci. Exact. 66: 580. 1990.

Type.

Brasil. Goiás : Chapada dos Veadeiros , "ca. 15 km W of Veadeiros ", 1000 m, 12 February 1966, fr., H.S. Irwin et al. 12681 (holotype: RB! [RB00540686]; isotypes: COL!, MO! [MO216832], NY! [NY00320735, NY00320738], US! [ US 00433287, US 00433288]) .

Description.

Trees ca. 15 m tall; branches cylindrical, with sparse lenticels, with cream-colored, tomentose and glabrescent trichomes, Stipules adnate to petiole, 0.5-1 cm long, green, oblong to conical, obtuse apex, truncate base, deciduous, tomentose when young. Petioles 2.3-6 cm long, stipule scar over its entire length (100%), yellowish-villous-tomentose trichomes when young. Leaf blades 9-19 cm × 5-9.2 cm, oval-elliptic, asymmetrical, apex obtuse-rounded, base cuneate-cordate, margin undulate, when young tomentose on abaxial side, glabrescent or trichomes persistent in herbarium material; venation pinnate, brochidodromous, abaxially slightly tomentose when young, adaxially glabrous, brown or yellowish; 6-11 pairs of secondary veins, glabrous, brown or yellowish. Peduncle cylindrical, tomentose at the annular scars, yellow trichomes or glabrescent, annular scars present. Flowers terminal, solitary, flower bud ovoid, 4.1 × 3.5 cm, white, glabrous, protected by the perula which is enclosing and protecting the flower bud, perula concave, brownish when dried; outer sepaloid tepals 3, 4,8-5 cm × 2,1-4 cm, cream-colored, navicular, spathulate, apex obtuse, base attenuate to truncate, glabrescent; inner petaloid tepals 6, 4,5-4,6 cm × 1,8-2,3 cm, navicular, spathulate, apex obtuse, base attenuate to truncate; stamens ca. 114, 1.2-1.4 cm × 0.1-0.2 mm, laminar, slightly falcate, arranged spirally in 4 series, apex obtuse, whitish to yellowish, thecae 2, introrse, dehiscence longitudinal; gynoecium conical to ellipsoid, slightly suberous, cream-colored, carpels ca. 111. Immature fruits 3-4 cm × 4.2-4.5 cm, obovoid to irregular shape, dehiscence circumscissile, in irregular syncarpous masses, yellow puberulent trichomes, seeds 1-2 per carpel.

Distribution and habitat.

Magnolia irwiniana occurs in tropical deciduous and riparian forests (next to watercourses). During collecting expeditions, it was found exactly in a saturation area, on waterlogged soil. It occurs in the Southeast ( São Paulo, Minas Gerais) and Central-West ( Goiás) regions.

Phenology.

The species was found with flowers between October and January and immature fruit was observed in mid-October and March.

Preliminary conservation status.

This species has been assessed as Endangered (EN) (Global Tree Specialist Group, 2014), which is here confirmed. The area of occupancy (AOO) is about 96.000 km2 and it is thus considered to be Endangered (EN) B2b (i,ii) ( IUCN 2022). Despite having a reasonable number of locations, it was observed during expeditions that the sites where the species was found were degraded or extremely fragmented (in one case having only one adult individual in an area), which exemplifies the serious decline in habitat.

Specimens examined.

Brasil. Distrito Federal: Brasília, Reserva ecológica do IBGE, proximidade do córrego Taquara, na divisa com Jardim Botânico de Brasília (Cristo) e Fazenda Água limpa-FAL-Unb, 13 Feb 2014, M. Aparecida da Silva 8015 (RB1140562); Goiás: Alto Paraíso de Goiás, Camping Portal da Chapada, Centro Oeste, Mata de galeria, 1164 m, 11 Jan 2002 L.H. Soares 1208 (RB534341); Chapada dos Veadeiros, gallery forest and adjacent campo. ca. 15 km. W. of Veadeiros, Goiás, 12 Fev 1966, H.C. Irwin 12681 (MO216832, NY320735, IAN137999); Margem esquerda do lago, cerca de 1,5 km após a Barragem (montante), 30 Marc 2005, A.A Santos 2576 (CEN66134); Near Pico dos Pirineus, 26 Jan 1968, H. S. Irwin et al. 3734 (US2221273); Teresina de Goiás, Estrada Alto Paraíso Teresina, 10 Out 1979, E. P. Heringer et al. 1658 (US3319311); Mato Grosso do Sul: Bataguassu, estrada para Anaurilândia, 19 Nov 1992, I. Cordeiro et al. 922 (SP268180); Estrada Bataguassu-Brasilândia, próximo a Bataguassu, 22 Nov 1991, I. Cordeiro 1030 (SP268194); Minas Gerais: Fazenda do Toninho, Alvinopolis, 15 Jun 1997, C.C Paula 1393 (VIC17332); Araponga, Pq Estadual, perto de um centro de pesquisa, 05 Jan 2008, B.S. Leoni 7072 (RB739528); Santos Drummont, Posses, Sítio Aracá, nascentes do córrego Araçá, 1000 m, 21°28'03"S, 43°39'26"W, 15 Oct 2003, R. Mello Silva 2168 (RB 394934); Córrego Do Bárbaro, Parque Nacional da Serra da Canastra, São Roque de Minas, 19 Oct 1997, J.N. Nakajima 2990 (ESA102608); Conceição do Mato Dentro, 10 Jan 2022, J.C.J. Barbosa et al. 14 (SP540865); Viçosa, 2 Nov 1935, C. Baez 1662 (RB210355); Viçosa, Estação de Pesquisa, Treinamento e Educação Ambiental, Mata do Paraíso, 13 Jun 2013, M.V.R.C Simão 326 (VIC40472); Sítio Bom Sucesso, fragmento de mata próximo de nascente de rio, 24 Nov 2021, J.C.J Barbosa & J.D.B. Miranda 11 (SP540864); São Paulo: Estação Ecológica Juréia-Itatins, Margens do Rio Verde, proximidades do Pocinho, 12 Marc 1992 S. Aragaki 13 (SP253046); São José do Barreiro, Fazendo Atibaia, Acesso pelo km 258 da Rodovia dos Tropeiro, Interior da Mata do Mascote, 4 Jul 2007, H. Serafim 276 (RB719859); Reserva Estadual do Morro do Diabo, Mun. Teodoro Sampaio ( à direita do Angelim), 28 Nov 1985, O.T Aguiar 152 (SPSF9544); Ubatuba, Praia de Itamambuca, 05 Feb 1996 H.F Leitão Filho et al. 34821 (SP295573).

Notes.

Magnolia irwiniana has been extensively confused with Magnolia ovata , but it can be easily distinguished by the asymmetrical leaf with undulate margin, and the presence of trichomes on its structures (vs. symmetrical leaf with entire margin and glabrous structures) and the high number of carpels, ca. 111 (vs. 68-71) (Figs 11 , 12 ).

Figures

Figure 6. Geographical distribution of Magnolia species in Brazil.

Figure 8. Magnolia irwiniana A herbarium specimen, asymmetrical leaves B detail of trichomes on the carpels C immature fruit D floral bud E detail of stipule and petiole scar. Photos: A: H. S Irwin 12681 (RB 540686); B: H. S Irwin 12681 (MO 216832) C-E: J. C. J. Barbosa.

Figure 11. A leaf blade Magnolia amazonica B trichomes from the petiole of M. amazonica C Magnolia brasiliensis D fruit with trichomes in M. brasiliensis E leaf blade M. brasiliensis F Magnolia ovata showing perule G floral bud of M. ovata H leaf blade of M. ovata I M. ovata mature fruit. (A-B: A. M Barreto 30; C-E: A. A. Grillo & M. Sztutman> s. n.; F-G: E. P. Heringer, 8726; H: R. R. Rodrigues et al. 161; I: based on photographs of J. C. J Barbosa.) Drawing prepared by Klei Souza.

Figure 12. A Magnolia irwiniana B presence of flower bud in M. irwiniana C leaf blade of M. irwiniana D detail of branch and stipule with trichomes in M. irwiniana E detail of the trichomes on the petiolar scars F immature fruit of M. irwiniana G detail of the puberulent trichomes on the fruit H Magnolia sellowiana I leaf blade M. sellowiana. (A: based on photographs of D. A. Zavatin; B: based on photographs of J. C. J. Barbosa C-G: H. F Leitao Filho et al. 34821; H: based on photographs of D. A. Zavatin; I: M. Kuhlmann 1809) Drawing prepared by Klei Souza.