An update to the palynotaxonomy of the Brazilian species of Aeschynomene sensu stricto and the recently circumscribed genus Ctenodon (Leguminosae – Papilionoideae – Dalbergieae)

Abstract

Pollen morphology and ultrasculpture are variable features and important tools to aid the taxonomy and systematics of Aeschynomene sensu stricto and the recently circumscribed genus Ctenodon. We performed a palynotaxonomy study of pollen morphology and ultrasculpture of nine species of Aeschynomene and 13 species of Ctenodon using light, scanning and electron transmission microscopy, and provided novel data for seven species. Additionally, principal components analysis was performed to elucidate patterns of quantitative data variation between species. Pollen is isopolar (rarely apolar and pantocolporate), small to medium in size, oblate to prolate, 3-zonocolporate or 3-parassyncolporate/3-syncolporate (only in A. americana) with a colporus with margo (the margo was rarely absent), membrane or/and operculum (the operculum was rarely absent), and a rugulate-perforate or nanoreticulate to reticulate sexine. Two pollen types are recognised, one for each genus, based on ultrasculpture variation of the colporus operculum, membrane and margo, and the mesocolpium and apocolpium sexine combined with endoaperture features. The eurypalynous morphology supports the current circumscription of these genera and their phylogenetic relationships.

Keywords:

• Aeschynomeneae
• Brazil
• Dalbergia clade
• Fabaceae
• granular infratectum
• palynology
• pollen morphology
• South America
• ultrasculpture

Acknowledgements

The authors are grateful to the SP, RB, MBM herbarium curators, who provided exsiccates and to Prof. Dr Ana Paula Fortuna-Perez, who kindly reviewed the manuscript. The authors also thank ‘Laboratório de Microscopia Eletrônica, Escola Superior de Agricultura Luiz de Queiroz, Universidade de São Paulo’ coordinated by Prof. Dr Elliot Watanabe Kitajima, who made the scanning electron microscope available and ‘Centro de Microscopia e Imagem, Faculdade de Odontologia de Piracicaba, Universidade de Campinas’ coordinated by Prof. Dr Pedro Duarte Novaes, for the use of the transmission electron microscope. The authors also extend their thanks to Dr Carin Stanski who provided the MBM herbarium flower buds.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Specimens investigated

Aeschynomene L. (asterisk [*] only for SEM and/or TEM images)

Aeschynomene americana L. Brazil: São Paulo, Guarulhos. R.T. Shirasuna & F. Morse 2195, 16 March 2009 (SP 488201); Brazil: São Paulo, Itu. M.G.L. Wanderley et al. 20, April 1995 (SP 285863*).

Aeschynomene denticulata Rudd. Brazil: Mato Grosso do Sul, Porto Murtinho. G. Hatschbach et al. 74233, 14 November 2002 (MBM 276632); Brazil: Mato Grosso do Sul, Porto Murtinho. E. Barbosa & J.M. Silva 1930, 16 November 2006 (MBM 325196).

Aeschynomene elaphroxylon (Guill. et Perr.) Taub. Brazil: Rio de Janeiro, Rio de Janeiro. S.M. Faria & H.C. Lima 119, 20 August 1984 (RB 335688).

Aeschynomene fluminensis var. tuberculata (Griseb.) Rudd. Brazil: Mato Grosso do Sul, Aquiduana. C. Hatschbach & O. Guimarães 21976, 18 July 1969 (SP 138102); Brazil: Mato Grosso do Sul, Campo grande. L.C.P. Lima et al. 105, 14 August 2001 (SP 367488).

Aeschynomene fructipendula Abruzzi de Oliveira. Brazil: Rio Grande do Sul, Osório. M.L. Abruzzi 2450, March 1991 (Paratypus) (HAS 32686).

Aeschynomene montevidensis Vog. Argentina: Buenos Aires, Delta del Paraná. A.C. Scala 179, January 1914 (SP 38908); Brazil: Paraná, Guaíra. M.M.R.F. Melo 328, 18 March 1982 (SP 209299); Brazil: Mato Grosso do Sul, Campo Grande. W.A. Archer & A Gehrt A s.n., 04 September 1936 (SP 36390); Uruguay: Rio San Juan Colonia, A.L. Cabrera 3217, 21 November 1934 (SP 38909).

Aeschynomene rudis Benth. Brazil: Maranhão, Viana. O. Carvalho 3, 23 July 1919 (SP 3427); Brazil: São Paulo, Cardoso. L.C. Bernacci 1845, 18 May 1995 (SP 310002); Brazil: Minas Gerais, Medica. G. Davidse & W.G.D’ Arcy 11565, 30 March 1976 (SP 160613*).

Aeschynomene selloi Vog. Brazil: São Paulo, São Paulo. B. Pickel 4441, 30 November 1939 (SP 42200); Brazil: Rio de Janeiro, Rio de Janeiro. F.C. Hoehne s.n., February 1917 (SP 24806); Argentina: Buenos Aires. A. Burkart 3630, 10 January 1931 (SP 28105).

Aeschynomene sensitiva Sw. Brazil: Paraná, Paranaguá. G. Tassmann, 21 December 1948 (SP 58253); Brazil: Maranhão, Loreto. G. Eiten & L.T. Eiten 4231, 11 April 1962 (SP 139230).

Aeschynomene sensitiva var. sensitiva Brazil: Mato Grosso do Sul, Ivinhema. L.C.P Lima et al. 155, 20 April 2002 (SP 367480); Brazil, Rio de Janeiro, Miguel Pereira Vera Cruz. N.L.A. Nunes 03, 13 March ?? (RB 470311); Brazil: Ceará, Mulungu. J.R. Lima 342, 12 November 2007 (RB 461043).

Aeschynomene sensitiva var. hispidula Rudd. Brazil: São Paulo, Campinas. L.Y.S Aona et al. 95/13, 23 March 1995 (SP 305414).

Aeschynomene sensitiva var. amazonica Rudd. Brazil: São Paulo, Dracena. A.D. Faria 96/102, 10 July 1996 (SP 305413*).

Ctenodon Baill. (asterisk [*] only for SEM and/or TEM images)

Ctenodon benthamii (Rudd) D.B.O.S. Cardoso, Filardi et H.C. Lima. Brazil: Espírito Santo, Venda Nova do Imigrante. G. Hatschbach 47689, 7 April 1985 (MBM 90065).

Ctenodon brevipes (Benth.) D.B.O.S. Cardoso, P.L.R. Moraes et H.C. Lima. Brazil: Bahia, Mucugê. J. E. Meireles et al. 706, 12 July 2009 (RB 489671); Brazil: Minas Gerais, Joaquim Felício Serra do Cabral. L.M. Borges et al. 640, 26 April 2012 (RB 608259).

Ctenodon elegans (Schltdl. et Cham.) D.B.O.S. Cardoso et A. Delgado. Brazil: São Paulo, São Paulo. J.R.L. Zamith 124, 01 January 1970 (SP 45342); Brazil: São Paulo, São Paulo. A. Gehrt s.n., 21 March 1930 (SP 25250); Brazil: Minas Gerais, Ouro Preto. H.C. Lima et al. 2655, 26 January 1986 (RB 241043).

Ctenodon falcatus (Poir.) D.B.O.S. Cardoso, P.L.R. Moraes et H.C. Lima. Brazil: São Paulo, Mogi Guaçu. W. Mantovani & M. Sugiyama 1643, 27 January 1981 (SP 168765); Brazil: São Paulo, Rancharia. V.C. Souza & J.P. Souza 10914, 14 February 1996 (SP 310005); Brazil: Paraná, Palmas. G. Hatschbach et al. 28200, 04 December 1971 (SP 138095).

Ctenodon genistoides (Taub.) D.B.O.S. Cardoso, Filardi et H.C. Lima. Brazil: Goiás, Alto Paraíso. G. Hatschbach, 37216, 27 September 1975 (MBM 37480).

Ctenodon histrix (Poir.) D.B.O.S. Cardoso, P.L.R. Moraes et H.C. Lima. Brazil: Piauí, Gilbués, Piaui. J.S. Silva 678, 27 May 1978 (SP 153559).

Ctenodon histrix var. densiflorus (Benth.) D.B.O.S. Cardoso, P.L.R. Moraes et H.C. Lima. Brazil: São Paulo, Itapeva. P.H. Miyagi et al. 297, 11 February 1995 (SP 287518); Brazil: Mato Grosso do Sul, Porto Murtinho. L.C.P. Lima et al. 78, 04 April 2001 (SP 36784); Brazil: São Paulo, São Jose do Rio Preto. J.R. Coleman 675, 2 February 1981 (SP 175266).

Ctenodon histrix var. incanus (Benth.) D.B.O.S. Cardoso, P.L.R. Moraes et H.C. Lima. Brazil: Maranhão, Loreto. G. Eiten & L.T. Eiten 4371A, 23 April 1962 (SP 82107); Brazil: Bahia, Barreiras. H.S. Irwin et al. 14927, 15 April 1966 (SP 108007); Brazil: Maranhão, Loreto. G. Eiten & L.T. Eiten 4289, 12 April 1962 (SP 139231).

Ctenodon martii (Benth.) D.B.O.S. Cardoso, P.L.R. Moraes et H.C. Lima. Brazil: Bahia, Macaúbas. H.P. Bautista & O.A. Salgado 857, 20 April 1984 (MBM 102591); Brazil: Bahia, Irecê. M.L. Guedes et al. 16217, 27 October 2009 (MBM 355373); Brazil: Bahia, Livramento do Brumado G.P. Lewis 1930, 1 April 1991 (MBM 147346)

Ctenodon molliculus (Kunth.) D.B.O.S. Cardoso, Filardi et H.C. Lima. Brazil: Minas Gerais, Francisco Sá. H.S. Irwin et al. 23192, 13 February 1969 (SP 140583); Brazil: Bahia, Contendas do Sincorá. G. Hatschbach 48369, 19 September 1985 (MBM 92295*).

Ctenodon paniculatus (Willd. ex Vogel) D.B.O.S. Cardoso, P.L.R. Moraes et H.C. Lima. Brazil: Mato Grosso do Sul, Três Lagoas. J. Correa-Gomes Jr 1778, 22 May 1964 (SP 314230); Brazil: Rio de Janeiro, Rio de Janeiro. J.A.L. Neto & L.F. Mentges 58, 14 April 1995 (RB 527521).

Ctenodon paucifolius (Vogel) D.B.O.S. Cardoso, Filardi et H.C. Lima. Brazil: Goiás, Posse. T.B. Cavalcanti et al. 762, 17 August 1990 (SP 77820); Brazil: Minas Gerais, Brejo das Almas. F. Markgraf et al. 3280, 10 November 1938 (SP 40566); Brazil: Mato Grosso, Barra das Garças. G. Eiten & L.T. Eiten 8870, 21 September 1968 (SP 131289).

Ctenodon racemosus (Vogel) D.B.O.S. Cardoso, Filardi et H.C. Lima. Brazil: São Paulo, Suzanápolis. M.R. Pereira-Noronha et al. 1530, 04 August 1995 (SP 306412); Brazil: Mato Grosso do Sul, Aquidauana. G. Hatschbach et al. 60679, 04 June 1994 (SP 330343); Brazil: Mato Grosso do Sul, Bataguassu. L.C.P. Lima et al. 162, 22 April 2002 (SP 367481); Brazil: Mato Grosso, Nova Xavantina. H.S. Irwin et al. 16115, 27 May 1966 (SP 108106).

Ctenodum viscidulus (Michx.) D.B.O.S. Cardoso et A. Delgado. Brazil: Sergipe, Aracaju. F. Barros 2407, 22 January 1992 (SP 259472).

Ctenodon vogelii (Rudd) D.B.O.S. Cardoso, Filardi et H.C. Lima. Brazil: Minas Gerais, Jaboticatubas. N.L. Menezes et al. 6366, 22 July 1980 (SP 166653); Brazil: Minas Gerais, Rio Vermelho. M.G.L. Wanderley et al. 4452, 14 July 1984 (SP 199425).

Additional information

Funding

This study was partially funded by ‘Coordenação de Aperfeiçoamento de Pessoal de Nível Superior’ – Brazil (CAPES) – Finance Code 001 (MSc Grant), awarded to HAD (process no. 88882.444252/2019-01); and by ‘Conselho Nacional de Desenvolvimento Científico e Tecnológico’ (CNPq), through research fellowships granted to CFPL (304271/2019-5) and APM (312602/2019-7).