Ceratonieae Rchb., Fl. Germ. Excurs. 2(2): 544. 1832.

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 Ceratonieae Rchb., Fl. Germ. Excurs. 2(2): 544. 1832.

Figs 6 , 7 , 8 , 9 , 10 , 11

Ceratoniinae H.S. Irwin & Barneby in R.M. Polhill & P.H. Raven, Adv. Legume System. 1: 98. 1981.

Type.

Ceratonia L.

Included genera

(4). Acrocarpus Wight ex Arn. (1 species), Arcoa Urb. (1), Ceratonia L. (2), Tetrapterocarpon Humbert (2).

Description.

Unarmed (rarely the stipules of juvenile leaves spinescent) shrubs or trees. Stipules spinescent ( Arcoa ), minute, caducous or lacking. Leaves pinnate or bipinnate with a terminal pinna. Inflorescences erect or pendent racemes or panicles, sometimes clustered on short shoots or ramiflorous. Flowers unisexual or bisexual, a short hypanthium usually present, and sometimes a prominent central pulviniform disk; sepals valvate to slightly imbricate; petals absent or 4-5 (6) per flower; androecium haplo- to diplostemonous, or occasionally stamens more than 2 × petal number. Fruits dehiscent or indehiscent, linear to linear-oblong with an adaxial narrow wing, or oblong-ellipsoid, or laterally compressed and 4-winged (the wings in two unequal pairs), 1-several-seeded. Seeds compressed, usually separated by areas of pulpy mesocarp, pleurogram lacking.

Distribution.

Highly disjunct in Hispaniola ( Arcoa ), Madagascar ( Tetrapterocarpon ), tropical (South-)East Asia ( Acrocarpus ), and north-eastern Africa, the Mediterranean, Oman, Yemen and Somalia ( Ceratonia ).

Clade-based definition.

The most inclusive crown clade containing Arcoa gonavensis Urb. and Ceratonia siliqua L., but not Umtiza listeriana Sim, Dimorphandra conjugata (Splitg.) Sandwith or Mimosa sensitiva L. (Fig. 6 ).

Notes.

The tribal name Ceratonieae was first published by Reichenbach (1832) to accommodate the genus Ceratonia . Irwin and Barneby (1981) placed Ceratonia in its own new subtribe Ceratoniinae H.S. Irwin & Barneby of tribe Cassieae , and they would have accorded the genus tribal rank, i.e., a reinstatement of Reichenbachʼs (1832) taxon, "if not dissuaded by others" ( Irwin and Barneby 1981: 98). Herendeen et al. (2003b), based on molecular and morphological data, grouped seven disparate caesalpinioid genera in their " Umtiza clade", which included two major subclades: the Arcoa - Tetrapterocarpon - Acrocarpus - Ceratonia clade and the Gymnocladus - Umtiza - Gleditsia clade. More recent studies do not support the monophyly of these two clades together ( Manzanilla and Bruneau 2012; LPWG 2013, 2017; Ringelberg et al. 2022) and they are here recognised under the two reinstated tribes Ceratonieae and Gleditsieae , respectively. Tribe Ceratonieae is resolved as sister to the rest of Caesalpinioideae (Fig. 6 ) and comprises six species in four genera (two of the genera are monospecific).

Only two characters have been found to be shared by members of tribe Ceratonieae : bipinnate leaves with a single terminal pinna (Fig. 7E ; although Ceratonia leaves are usually singly pinnate) and three of the four genera (all except Arcoa , which is sister to the three other genera) have a large deletion in the plastid trnL intron ( Bruneau et al. 2001). Three of the genera ( Acrocarpus is the exception) are dioecious (although occasional bisexual flowers occur). Ceratonia and Acrocarpus are sister genera, both have simple inflorescences, a haplostemonous androecium, glabrous stamen filaments, alternate first seedling leaves, septate wood fibres, and a chromosome base number of x = 12. They differ in unisexual ( Ceratonia ) versus bisexual ( Acrocarpus ) flowers, absence of petals ( Ceratonia ) versus petals present ( Acrocarpus ), and fruit type: indehiscent ( Ceratonia ) versus dehiscent ( Acrocarpus ). Three of the four genera are confirmed as non-nodulating and the status of Tetrapterocarpon is not known ( Sprent 2001; Faria et al. 2022).

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 7. Flower, fruit, and vegetative characters of tribe Ceratonieae A Arcoa gonavensis Urb., foliage and fruits, Dominican Republic B Tetrapterocarpon geayi Humbert, fruits and part of bipinnate leaf, Madagascar (Du Puy M 410) C-E Acrocarpus fraxinifolius Wight & Arn., India, cultivated tree C inflorescence D dehisced fruits and new flush foliage E part of a bipinnate leaf F-J Ceratonia siliqua L. F tree, Jordan, semi-desert near Petra G fruits, Israel, Mt. Scopus Botanical Gardens, Jerusalem H pistillate flowers, Crete I staminate flowers, Crete J staminate inflorescences, Israel, Jerusalem Botanical Gardens. Photo credits A F Jimenez R. B D Du Puy C-E https: // efloraofindia. com / 2011 / 02 / 01 / acrocarpus-fraxinifolius / E D Valke F, G, J O Fragman-Sapir H, I G Lewis.

Figure 8. Distribution of Arcoa based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.

Figure 9. Distribution of Tetrapterocarpon based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.

Figure 10. Distribution of Acrocarpus based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.

Figure 11. Distribution of Ceratonia based on quality-controlled digitised herbarium records. Note that many distribution points observed here are from cultivated Ceratonia specimens. The true native range of the genus Ceratonia is likely to be more restricted than depicted on the map. See Suppl. material 1 for the source of occurrence data.