Magnolia amazonica (Ducke) Govaerts, World Checkl. Bibliogr. Magnoliaceae, 70. 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 amazonica (Ducke) Govaerts, World Checkl. Bibliogr. Magnoliaceae, 70. 1996.

Figs 5 , 6 , 11

Talauma amazonica ≡ Talauma amazonica Ducke, Arch. Jard. Bot. Rio de Janeiro 4: 11. 1925.

Type.

Brasil. " Prope medium flumen Tapajoz civitatis Pará loco Francez ", fl, 10 January 1922, A. Ducke 12487 (holotype: RB! [RB00540679]; isotypes: B! [B10 0248229],BM! [BM000551380, BM000551379], G! [G00352605], K! [K000470024, K000470025], P! [P00734783], R! [R000024142], RB! [RB00556527, RB00556528], S! [SR6051]) .

Description.

Trees 15-20 m tall; branches cylindrical, yellowish-brown, lenticulate, tomentose at annular scars closest to the flower bud, trichomes yellowish. Stipules adnate to petiole, green, oblong to conical, apex obtuse, base truncate, deciduous, tomentose. Petioles 1.8-5 cm long, stipular scar ranging from 90% to 100% of its length, tomentose when young and short, trichomes glabrescent. Leaf blades 11-28 cm × 4-12.4 cm, elliptic, base cuneate to acute, apex acute, margin entire; slightly coriaceous; venation pinnate, brochidodromous, 8-19 pairs of secondary veins irregularly spaced apart; when young tomentose abaxially, adaxially glabrous, yellowish-green. Peduncle cylindrical, tomentose at the annular scars, yellow trichomes, annular scars present. Flowers terminal, solitary; flower bud 3.95-6.34 cm × 3.25-4.70 cm, ovoid, yellowish-white, glabrous, protected by perula enveloping and protecting the flower bud, perula concave, brownish when dried; outer sepalloid tepals 3, 5-7 × 3-4 cm, asymmetrical, base cuneate, apex rounded, yellowish when dry; inner petaloid tepals 6, 6-7 cm × 3-5 cm, oblong, base attenuate, apex rounded, brown when dry; stamens ca. 100, laminar, slightly falcate, spirally arranged in 4-5 series, apex obtuse, whitish to yellowish, thecae 2, anthers introrse, dehiscence longitudinal; gynoecium 1.97 cm × 1.78 cm, conical, yellowish, carpels ca. 46. Immature fruits 4.4-5.5 cm long, 5 cm in diameter, globose, with puberulent pubescence, dehiscence circumscissile, in irregular syncarpous masses; seeds 1-2 per carpel, sarcotesta red.

Distribution and habitat.

Magnolia amazonica is the only Brazilian Magnolia known from the Amazon region. In Brazil, it is found in the North (Amazonas and Pará) and Southeast (Rio de Janeiro) regions, and it is also known from the tropical forests of Peru and Bolivia ( Lozano-Contreras 1990), although other species have been recently described there, being segregated from this species, e.g. M. peruviana A. Vázquez. As a consequence, the presence and distribution of M. amazonica in that country needs further investigation. Magnolia amazonica is a perennial tree that grows up to 20 m tall in Amazon rainforest.

Phenology.

Its creamy-white flowers open at night and were collected in mid-January. Its fruits were observed in mid-July ( Ducke 1925).

Preliminary conservation status.

This species has previously been assessed as Least Concern (LC) ( Khela 2014). However, in this analysis (Brazilian specimens) its area of occupancy (AOO) is about 44.000 km2 and it is considered to be Endangered (EN) B2b (i,ii) ( IUCN 2022). It is likely that this species is declining due to deforestation and land use changes, especially in the northern region of the country, where unfortunately there are flawed laws regarding preservation ( Gonçalves et al. 2010). In addition, with the recent description of a Magnolia species in its distribution area in Peru ( M. peruviana ), the delimitation of M. amazonica may be narrowed in the future, with further studies. Therefore, the conservation status will also likely need to be updated.

Specimens examined.

Brasil. Pará: Novo Progresso, Serra do Cachimbo, Area da Aeronautica torre 2 do Stand de tiro, mata de transição com campinarana, solo areno-argiloso, 9°19'16"S a 9°16'196"S, 54°59'42"W a 54°56'222"W, 20 Aug 2003, A.S.L. Silva 3967 (RB787799) ; Rio de Janeiro: Município Silva Jardim, Reserva Biológica de Poço das Antas, Trilha do Morro do Calcario , 22°30'/ 22°33'S, 42°15'/ 42°19'W, 5 Mar 1993, S.M. Barreto 30 (RB300133); Nova Iguaçu, Margem do Brejo do Macuco , 12 Dec 2001, S.J. Silva Neto & M.V. Pereira-Moura 1573 (RB364320); Nova Iguaçu, Região SE, Rebio, Tinguá, Estrada do Ouro , Ponto 154, Planalto próximo a entrada para Igrejinha de Santana , 600 msm, 22°33'56.9"S, 43°28'11.2"W), 25 Jan 2006, R.D. Ribeiro 569 (RB419738) .

Notes.

Magnolia amazonica is recognized by its puberulent-tomentose pubescence (on several of its structures, e.g., branches, stipules, petioles (Table 1 ), and can be found in the Amazon region of the country.

The specimen A.S.L. Silva 3967 in the herbarium of the Botanical Garden of Rio de Janeiro (RB787799) had been erroneously identified as M. ovata , likely because of the similarity in the leaf shape between both species. However, they can be differentiated by the absence of trichomes in M. ovata (vs. trichomes present on petiole and branches in M. amazonica ) and the number of carpels: 144-150 in M. ovata vs. 98-102 in M. amazonica .

Figures

Figure 5. Magnolia amazonica A-C specimen deposited in herbarium D-E detail petiole and peduncle (in the region of the annular scars) showing trichomes in the youngest structures F gynoecium. Photos: A-C W. A. Ducke 12487 (R 000024142; BM 000551380); B-D: (B 100248229); C-F: BM 551380; F: I. M. Silva 471 NY 03097880.

Figure 6. Geographical distribution of Magnolia species in Brazil.

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.