Chidlowia Hoyle, Bull. Misc. Inform. Kew 1932 (2): 101. 1932.

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

Chidlowia Hoyle, Bull. Misc. Inform. Kew 1932 (2): 101. 1932.

Figs 114 , 117 , 118

Type.

Chidlowia sanguinea Hoyle

Chidlowia is here considered a monospecific lineage, whose relationship to other Mimoseae remains difficult to determine. In all phylogenetic analyses in which the genus is included, it is resolved as a distinct lineage, generally on a long branch, but strongly supported within Mimoseae ( Manzanilla and Bruneau 2012; LPWG 2017; Koenen et al. 2020a; Ringelberg et al. 2022). Here it is resolved as nested between the Adenanthera and Entada clades, in a grade with another distinct lineage, Sympetalandra Stapf, but with no clear affinities between these two genera or with these two clades (Fig. 114 ).

Description.

Unarmed tree, small to medium sized, up to 25 (30) m (Fig. 117A ) with many adventitious stems; bark very rough, grey to brown with many lenticels (Fig. 117B ). Stipules small, caducous. Leaves parapinnate (Fig. 117C ), up to 25 cm long; petiole terete, up to 2.5 cm long; leaflets 4-6 pairs opposite or subopposite, 4-12 × 2-5 cm. Inflorescence a slender, pendulous panicle (Fig. 117D, E ), to 40 cm long, usually on old wood or terminal on young branchlets; lateral branchlets numerous and short, 5-7-flowered; bracts and bracteoles minute, caducous. Flowers deep red (Fig. 117F ); pedicels slender, 3-3.5 mm; calyx campanulate, ca. 2 mm long with 5 short rounded teeth; disk fleshy, campanulate, adnate to base of calyx tube; petals free, 5 subequal, 6-7 mm long; stamens 10, partly joined at the base, red; pollen in monads, coarsely reticulate exine with foramina ( Banks et al. 2003); ovary stipitate, style long and red. Fruit oblong-linear, acute at both ends, up to 60 cm long and 6 cm broad, valves coriaceous woody (Fig. 117G, H ), dehiscing elastically along both sutures, separately spirally twisting, 9-14 (15) seeds. Seeds suborbicular, flat, shining red-brown, testa coriaceous; funiculus less than 1 mm long; hilum concealed by funicular remnant; pleurogram absent.

Chromosome number.

Unknown.

Included species and geographic distribution.

Monospecific ( C. sanguinea ), West tropical Africa in Ghana, Guinea, Ivory Coast, Liberia, Sierra Leone (Fig. 118 ).

Ecology.

Trees of evergreen and moist semi-deciduous Guineo-Congolian forest.

Etymology.

Named in honour of English silviculturist, Chidlow Vigne, who worked at the Gold Coast Forest Service, and was the first collector to recognise the distinctiveness of specimens of this species.

Human uses.

In Ivory Coast the wood, which is very hard and known as ‘bala’, is locally used for joinery, stakes and rifle butts ( Lemmens 2010).

Notes.

Chidlowia was placed in the Dimorphandra group of tribe Caesalpinieae by Polhill and Vidal (1981), Polhill (1994) and Lewis (2005b) but resolved as part of the mimosoid clade when first sampled in a molecular phylogenetic analysis ( Manzanilla and Bruneau 2012), a placement that has subsequently been confirmed with additional data ( LPWG 2017; Koenen et al. 2020a; Ringelberg et al. 2022). Morphologically, members of the informal Dimorphandra group of Polhill and Vidal (1981) were known to have similarities to mimosoid legumes and the group was considered a ‘‘ transitional link’’ between the caesalpinioids and mimosoids ( Polhill and Vidal 1981; Luckow et al. 2000, 2003).

In Chidlowia , the singly pinnate leaves, relatively large flowers with showy red petals which are strongly imbricate in bud, the large explosively dehiscent woody fruits, and seeds lacking a pleurogram are all more suggestive of placement outside the mimosoids. Hoyle (1932) had suggested an affinity with the genus Schotia Jacq. (subfamily Detarioideae ), but the regular flowers with equally sized petals, the showy red stamen filaments partly joined at the base (described as free by Hoyle (1932) in the genus protologue), and the small campanulate, gamosepalous calyx, support placement in Mimoseae . Chidlowia also stands out in having dorsifixed (not basifixed) anthers.

Chidlowia has flowers similar to those found in Sympetalandra with a fleshy and thick floral disc joined to the base of the calyx, petals and stamens simulating a hypanthium ( Hoyle 1932). These two genera could be considered as morphologically aberrant in Mimoseae , because of the paripinnate leaves and the imbricate ascending petals. However, paripinnate leaves occur in other Mimoseae genera, such as the speciose genus Inga Mill. and in some species of Zygia P. Browne. Additionally, Chidlowia shares with other nodulating Mimosae a symbiosome root nodule anatomy, whereby rhizobia are symplastically retained in the host cell cytoplasm within membrane-bound symbiosomes ( Faria et al. 2022).

Taxonomic references.

Hoyle (1932); Hutchinson and Dalziel (1958).

Figures

Figure 114. Phylogenetic position of Sympetalandra and Chidlowia in tribe Mimoseae. For description of phylogeny and support values, see Fig. 6 caption (page 63).

Figure 117. Chidlowia sanguinea Hoyle A tree with steep buttresses and twisted trunk B bark greyish to brownish with many lenticels, inner bark pink to reddish brown C parapinnate leaves with 4 - 6 pairs of leaflets D inflorescence, long and pendulous panicle E tip of inflorescence showing multiple buds F deep red flowers with long stamens and style G fruit, with coriaceous woody valves H dehisced fruit showing under-developed seed remnants. Photo credits A-C C Jongkind (WAG) D-H X van der Burgt (K).

Figure 118. Distribution of Chidlowia based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.