Taxonomic revision of the native Magnolia (Magnoliaceae) species of Brazil

Abstract

The genus Magnolia (Magnoliaceae) has a wide and disjunct geographic distribution ranging from Eastern and South Asia to Malaysia, extending across the Neartics and reaching into the Neotropics. Regarding its infrageneric classification, the genus is divided into three subgenera: Yulania, Gynopodium and Magnolia, the latter including the section Talauma in which the native Brazilian taxa are classified. The species of Magnoliasect.Talauma can be recognized by two parallel longitudinal scars on the petiole formed by the shedding of the stipules, in addition to a woody syncarp that breaks into irregular plates at dehiscence. Currently, in Brazil, species recognition is not clear on national platforms that are widely used by the Brazilian botanical community (e.g. Flora do Brasil), with only two native Magnolia species being accepted: M.amazonica and M.ovata. The lack of knowledge about the species and their respective characteristics has resulted in many identification errors in Brazilian herbaria, which contributes to the lack of knowledge about their current conservation status. We conducted a complete taxonomic revision based on extensive fieldwork, a herbarium survey, along with literature study. Based on this, we propose to recognize three previously described species, supporting the acceptance of five native Magnolias occurring in Brazil, namely: M.amazonica, M.brasiliensis, M.irwiniana, M.ovata and M.sellowiana. However, we follow the Flora do Brasil in maintaining M.paranaensis as a synonym of M.ovata. Additionally, we designate a lectotype for M.sellowiana. We present morphological descriptions and the geographic distribution for each species, in addition to an identification key to all of these plus the two introduced ornamental species from Asia and North America, illustrations, photographs, ecological data, updated conservation status and taxonomic notes.

Keywords: Brazilian Flora; Magnolioideae; Neotropics; Pinha-do-brejo; conservation; distribution; sect. Talauma; taxonomy.

Figure 1.

A branch with alternate leaves, present stipules, and terminal flower, v. detail of central vein, vb. detail of brochidodromous venation B detail of the branch showing scars C adnation of the stipule (which later falls) on the petiole, a characteristic of MagnoliasectionTalauma; ca. Annular scar; cp. Petiolar scar (resulting from stipule fall). Photos: A, v, vb, ca, cp: D.A. Zavatin; B-C: J. C. J. Barbosa.

Figure 2.

Magnolia flower stages A perule B immature floral bud C mature floral buds D, F flower at anthesis; br. Sepaloid tepal te. Petaloid tepal; gi. Flower with detail of the gynoecium E stamen. Photos: A: U. Pastore & R.M. Klein 145 (MBM115080); B-C: J. C. J. Barbosa; D, bra, te: D. A. Zavatin.

Figure 3.

A gynoecium, vertical view B gynoecium, viewed from above ce. Staminal scar, cpl. petaloid scar, pi. Pistillum, es. Stigma C longitudinal section, receptacle and gynoecium D detail ovary, ov. ovule. Photos: D. A. Zavatin.

Figure 4.

Fruit stages A partially open syncarpous fruit B detail of the inner woody part of the fruit C 1–2 seeds per carpel D mature fruit, with open woody masses (seeds already fallen from the fruit) Photos: J. C. J Barbosa.

Figure 5.

MagnoliaamazonicaA–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–CW.A. Ducke 12487 (R000024142; BM000551380); B–D: (B100248229); C–F: BM551380; F: I. M. Silva 471 NY 03097880.

Figure 6.

Geographical distribution of Magnolia species in Brazil.

Figure 7.

MagnoliabrasiliensisA habit B immature gynoecium C immature fruit D bracts (perule) and gynoecium E details of trichomes on the fruit F specimen deposited in the RB herbarium showing coriaceous leaves. Photos: A–D: C. O. Azevedo; E: R. Mello-Silva 50 (RB409806); F: L.M. Borges 393 (RB664467).

Figure 8.

MagnoliairwinianaA 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 9.

MagnoliaovataA specimen deposited in herbarium P B mature gynoecium C specimen deposited in herbarium SPSF D longitudinal section of flower bud (gynoecium and stamens) E immature fruit F annular and petiolar scars. Photos: A: Saint-Hilaire s.n (P00734792); B: Irwin >s.n (RB161815); C: O.C. Pavão et al. (SPSF28228); D: R. Marquete 2596 (RB398212); E–F: J. C. J. Barbosa.

Figure 10.

MagnoliasellowianaA specimen deposited in herbarium P showing broadly elliptic leaf B specimen deposited in herbarium MBM C flower, detail of gynoecium and stamens D stipule with trichomes E midvein with trichomes. Photos: A: A.Saint-Hilaire s.n. (P00734795); B: U. Pastore & R.M Klein 145 (MBM 115080); C–E: L.S. Leoni 2689 (RB739505).

Figure 11.

A leaf blade MagnoliaamazonicaB trichomes from the petiole of M.amazonicaCMagnoliabrasiliensisD fruit with trichomes in M.brasiliensisE leaf blade M.brasiliensisFMagnoliaovata showing perule G floral bud of M.ovataH leaf blade of M.ovataIM.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.

AMagnoliairwinianaB presence of flower bud in M.irwinianaC leaf blade of M.irwinianaD detail of branch and stipule with trichomes in M.irwinianaE detail of the trichomes on the petiolar scars F immature fruit of M.irwinianaG detail of the puberulent trichomes on the fruit HMagnoliasellowianaI 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 Leitão Filho et al. 34821; H: based on photographs of D. A. Zavatin; I: M. Kuhlmann 1809) Drawing prepared by Klei Souza.