Dimorphandreae Benth., J. Bot. (Hooker) 2: 74. 1840.

Bruneau, Anne, de Queiroz, Luciano Paganucci, Ringelberg, Jens J., Borges, Leonardo M., Bortoluzzi, Roseli Lopes da Costa, Brown, Gillian K., Cardoso, Domingos B. O. S., Clark, Ruth P., Conceicao, Adilva de Souza, Cota, Matheus Martins Teixeira, Demeulenaere, Else, de Stefano, Rodrigo Duno, Ebinger, John E., Ferm, Julia, Fonseca-Cortes, Andres, Gagnon, Edeline, Grether, Rosaura, Guerra, Ethiene, Haston, Elspeth, Herendeen, Patrick S., Hernandez, Hector M., Hopkins, Helen C. F., Huamantupa-Chuquimaco, Isau, Hughes, Colin E., Ickert-Bond, Stefanie M., Iganci, Joao, Koenen, Erik J. M., Lewis, Gwilym P., de Lima, Haroldo Cavalcante, de Lima, Alexandre Gibau, Luckow, Melissa, Marazzi, Brigitte, Maslin, Bruce R., Morales, Matias, Morim, Marli Pires, Murphy, Daniel J., O'Donnell, Shawn A., Oliveira, Filipe Gomes, Oliveira, Ana Carla da Silva, Rando, Juliana Gastaldello, Ribeiro, Petala Gomes, Ribeiro, Carolina Lima, Santos, Felipe da Silva, Seigler, David S., da Silva, Guilherme Sousa, Simon, Marcelo F., Soares, Marcos Vinicius Batista & Terra, Vanessa, 2024, Advances in Legume Systematics 14. Classification of Caesalpinioideae. Part 2: Higher-level classification, PhytoKeys 240, pp. 1-552 : 1

Tribe Dimorphandreae Benth., J. Bot. (Hooker) 2: 74. 1840.

Figs 87 , 88 , 89 , 90 , 91 , 92 , 93

Dimorphandrinae Walp., Repert. Bot. Syst. 1: 854. 1843. Type: Dimorphandra Schott

Moreae Britton & Rose, N. Amer. Fl. 23: 201, 217. 1930. Type: Mora Benth.

Type.

Dimorphandra Schott

Included genera

(4). Burkea Hook. (1 species), Dimorphandra Schott (26), Mora Benth. (6), Stachyothyrsus Harms (2).

Description.

Unarmed shrubs, treelets to canopy trees up to 40 m high; trunk buttressed or not; brachyblasts absent; branches glabrous or pilose. Stipules present or absent. Leaves pinnate or bipinnate; extrafloral nectaries on the petiole occurring only in Stachyothyrsus ; pinnae (in bipinnate leaves) 1-many pairs; leaflets 1-many pairs, opposite or alternate, variable in size and shape. Inflorescences short or elongated spiciform racemes or spikes, often arranged in corymbose or paniculate synflorescences; bracteoles small or absent. Flowers 5-merous, diplostemonous; stamens alternate, sometimes with 5 fertile and 5 staminodes; anther glands absent or present ( Burkea ); pollen tricolpate monads. Fruit a typical legume or samara ( Burkea ), dehiscent or indehiscent, variable in size and shape, 1-multiseeded. Seeds flat-compressed to ovoid, with a hard or thin testa, areolas absent, present on both sides only in Burkea .

Distribution.

Rainforests, seasonally dry forests, and savannas, in tropical regions of the Americas and Africa.

Clade-based definition.

The most inclusive crown clade containing Dimorphandra gardneriana Tul. and Burkea africana Hook., but not Campsiandra comosa Benth., Tachigali guianensis (Benth.) Zarucchi & Herend. or Schizolobium parahyba (Vell.) S.F. Blake (Fig. 87 ).

Notes.

The informal Dimorphandra group of the old sense subfamily Caesalpinioideae , which originally included 10 genera ( Polhill and Vidal 1981; Polhill 1994), has been shown to be non-monophyletic ( Bruneau et al. 2001, 2008; LPWG 2017), but the four genera included here in Dimorphandreae have been supported as a clade in these previous analyses, albeit with low support and poor resolution amongst the genera. The phylogenomic analyses of Ringelberg et al. (2022) support the monophyly of the tribe and reveals an amphi-Atlantic distribution, with the two South American genera, Dimorphandra and Mora , sequentially sister to the two African genera, Burkea and Stachyothyrsus .

Members of the Dimorphandreae (Figs 88 , 89 ) are unarmed trees, with leaves lacking extrafloral nectaries (except Stachyothyrsus ). They have spicate inflorescences, 5-merous diplostemonous flowers lacking anther glands (except Burkea ), with a short style, and tricolpate single-celled pollen grains. Within Dimorphandreae , Mora is morphologically similar to Dimorphandra , sharing flowers with five fertile stamens and five staminodes, but can be readily distinguished by once pinnate, glabrous leaves (vs. bipinnate and pubescent in Dimorphandra ), and seed size (much larger in Mora ). The African sister genera Stachyothyrsus and Burkea share stamens arising at the insertion or just slightly above the ovary insertion ( Cowan 1981a). Within the tribe, Stachyothyrsus can be recognised by the dimorphic stamens and presence of petiolar nectaries, while Burkea is distinguished by inflorescences and young leaves clustered at the tip of shoots and fruits bearing a single seed. Bees are the main pollinating agents for species of the tribe, as described for Burkea and some species of Dimorphandra and Mora ( Silva 1986), and possibly Stachyothyrsus ( Brink 2010). A survey including several representatives of the tribe recorded single-grain, tricolpate pollen ( Banks and Lewis 2009). Seed dispersal varies in the group.

Although Dimorphandreae forms a well-supported clade, Dimorphandra , the largest genus in the tribe, was recovered as non-monophyletic (Fig. 87 ), and new generic circumscriptions are required.

Figures

Figure 6. Generic relationships in tribe Ceratonieae. Left part of figure shows complete genus-level Caesalpinioideae phylogeny with the Ceratonieae indicated with a red rectangle. Branch lengths are expressed in coalescent units and terminal branches were assigned an arbitrary uniform length for visual clarity. Support for relationships is based on fractions of supporting and conflicting gene trees: pie charts show gene tree support and conflict per node (blue representing supporting gene trees, green gene trees supporting the most common alternative topology, red gene trees supporting further alternative topologies, grey gene trees uninformative for this node), and numbers above pie charts are Internode Certainty All support values [both calculated with PhyParts (Smith et al. 2015)]. If present, red numbers below pie charts are non-significant (i. e.> 0.05) outcomes of ASTRAL's polytomy test (Sayyari and Mirarab 2018), which tests for each node whether the polytomy null model can be rejected. Monophyletic genera are represented by single branches; see Suppl. material 2 for a phylogeny with all accessions. See Suppl. material 3 for gene tree support across the phylogeny. The phylogeny is a pruned version of the backbone phylogeny of Ringelberg et al. (2023), where full details of the data and phylogenomic analysis methods are presented.

Figure 87. Generic relationships in tribe Dimorphandreae. For description of phylogeny and support values, see Fig. 6 caption (page 63).

Figure 88. Leaves and inflorescences of tribe Dimorphandreae A Mora paraensis (Ducke) Ducke (Simon 1663) B Stachyothyrsus staudtii Harms C Burkea africana Hook. D Dimorphandra mediocris Ducke (Simon 4209) E Dimorphandra cuprea Sprague & Sandwith (Farronay 1804) F Dimorphandra parviflora Spruce ex Benth. (Simon 1176) G Dimorphandra mollis Benth. H Dimorphandra pennigera Tul. I Dimorphandra ignea Ducke J Dimorphandra vernicosa Spreng. ex Benth. (Cardoso 3279) K Burkea africana L Dimorphandra gardneriana Tul. (Silva 21). Photo credits A, D, F, G MF Simon B Nicolas Texier (CC-BY-NC-ND- 3.0) C AR Lecuona (CC-BY-NC- 4.0) E, H, I F Javier Farronay Pacaya J D Cardoso K AE van Wyk and S Malan L G Sousa da Silva.

Figure 89. Flowers and fruits of the tribe Dimorphandreae A Dimorphandra cuprea Sprague & Sandwith (Farronay 1804) B Dimorphandra pennigera Tul. C Dimorphandra vernicosa Spreng. ex Benth. (Cardoso 3279) D Dimorphandra ignea Ducke E Stachyothyrsus staudtii Harms F Dimorphandra gardneriana Tul. (Simon 2715) G Dimorphandra macrostachya Benth. (Silva 540) H Dimorphandra cuprea Sprague & Sandwith (Farronay 1804) I Stachyothyrsus staudtii Harms J Burkea africana Hook. K-M Mora paraensis (Ducke) Ducke (K, L Costa 28). Photo credits A, B, D, H F Javier Farronay Pacaya C D Cardoso E Flora of the world F MF Simon G G Sousa da Silva I N Texier (CC-BY-NC-ND- 3.0) J C Sydes (CC-BY-NC- 4.0) K, L J Barbosa Pedrosa Costa M A Rocha Dantas.

Figure 90. Distribution of Dimorphandra based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.

Figure 91. Distribution of Mora based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.

Figure 92. Distribution of Stachyothyrsus based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.

Figure 93. Distribution of Burkea based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.