Indopiptadenia Brenan, Kew Bull. 10(2): 178. 1955.

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

Indopiptadenia Brenan, Kew Bull. 10(2): 178. 1955.

Figs 135 , 136

Type.

Indopiptadenia oudhensis (Brandis) Brenan [≡ Piptadenia oudhensis Brandis]

Description.

Trees 3-12 m tall (Fig. 135A ), variably unarmed or armed with scattered internodal prickles on shoots, and trunk with prominent scattered conical protuberances terminating in a sharp point (Fig. 135B, C ); brachyblasts absent. Stipules small, lanceolate, caducous. Leaves bipinnate, extrafloral nectaries between first pair of pinnae or at apex of petiole and often between leaflets, shallow cupular or flat and pad-like, oval; pinnae 1-2 pairs, opposite; leaflets 1 (2) pairs per pinna, opposite, venation pinnate, brochidodromous. Inflorescence a spiciform raceme, not enveloped in fused bracts; solitary in leaf axils or grouped in secondary terminal racemes (Fig. 135F ); pedicels flattened, pad-like, somewhat glandular, persistent on the receptacle after anthesis. Flowers greenish-yellow, lacking a hypanthium; sepals 5, valvate; petals 5, free, valvate; stamens 10, free, anthers dorsifixed, bearing a minute, deciduous claviform apical gland of the piptadenioid type (sensu Luckow and Grimes 1997); pollen in tricolporate monads, exine smooth (perforated), columellae present; ovary sessile, stigma funnel-shaped. Fruits straight, plano-compressed, narrowly linear (Fig. 135H ), 15-20-seeded, valves coriaceous, dehiscent through both sutures. Seeds oblique, strongly flattened with a membranous wing, pleurogram absent, testa thin, funicle attached medially.

Chromosome number.

Unknown.

Included species and geographic distribution.

Monospecific ( I. oudhensis ), occupying a narrow band restricted to the Terai region of the outlying lowest foothills of the Himalayas at scattered localities almost entirely within Nepal and just barely traversing the border into northern India in a few places (Fig. 136 ).

Ecology.

Seasonal deciduous or semi-evergreen monsoon forests and disturbed riverine vegetation (Fig. 135A ) in the outlying foothills of the Himalayas, at 150-900 m elevation, mainly in gravelly and sandy soils. Deciduous. Seed dispersal passive, or possibly wind-dispersed.

Etymology.

Indopiptadenia refers to the superficial resemblance to the genus Piptadenia and Indo- (from India).

Human uses.

The leaves are used locally for fodder and the wood as fuel and timber. The wood is very hard, strong, and durable ( Bajpai et al. 2014).

Notes.

Indopiptadenia remained poorly known, based on just a handful of collections, until Bajpai et al. (2014) published a detailed and amply illustrated account of the morphology and distribution of the genus. Indopiptadenia was segregated from Piptadenia by Brenan (1955) and later placed in the informal Newtonia group ( Lewis and Elias 1981). Indopiptadenia is now known to be robustly supported as sister to the re-circumscribed Prosopis s.s. (Fig. 132 ; Hughes et al. 2022a; Ringelberg et al. 2022). Originally described as unarmed, Indopiptadenia often has small internodal prickles (shared with Prosopis s.s.) and characteristic conical sharply-tipped woody protuberances on the mature stems (Fig. 135B, C ), strongly reminiscent of the stems of young trees of Cylicodiscus (Fig. 133C ). The rupturing of the walls in immature fruits observed by Bajpai et al. (2014) is probably attributable to damage to the fruits, possibly by birds.

Taxonomic references.

Bajpai et al. (2014); Brenan (1955); Duthie (1906), with illustration.

Figures

Figure 132. Phylogeny showing the relationships among Cylicodiscus and the genera of the Prosopis clade and the Neltuma clade, the first-branching lineages of the core mimosoid clade of tribe Mimoseae. Substantial gene tree conflict is associated with the relationships of Cylicodiscus which is separated from the Prosopis clade by a very short branch (see inset for exact branch lengths printed above branches). For description of phylogeny and support values, see Fig. 6 caption (page 63).

Figure 133. Habit, leaves, flowers and fruits of Cylicodiscus in wet tropical forest in west Africa A, B Cylicodiscus gabunensis Harms, large canopy emergent tree C mature tree trunk with large knee-like buttresses D immature understory sapling showing sharp-pointed woody protuberances on stem E leaves showing leaflets with conspicuous drip tips F inflorescences G strap-like legumes (ca. 1 m long) showing follicular dehiscence H canopy-emergent tree crown with long strap-like pendulous fruits I 12 cm long winged seeds. Photo credits A, B, D, E, G W Hawthorne C X van der Burgt F, H, I R Ndonda Makemba.

Figure 135. Habit, armature, inflorescences, and fruits of genera of the Prosopis clade A Small tree of Indopiptadenia oudhensis (Brandis) Brenan in disturbed seasonal monsoon vegetation in Uttar Pradesh, northern India B, C scattered internodal sharply tipped woody protuberances on trunk and branches of young Indopiptadenia oudhensis trees in Uttar Pradesh, northern India D trees of Prosopis cineraria (L.) Druce lopped for animal fodder on the arid fringes of the Thar desert, Rajasthan, India E internodal prickles on young shoot of Prosopis farcta (Banks & Sol.) J. F. Macbride F inflorescences of Indipiptadenia oudhensis in Uttar Pradesh, northern India G inflorescences of Prosopis farcta H unripe, plano-compressed fruits of Indopiptadenia oudhensis in Uttar Pradesh, northern India I indehiscent fruits with a thickened mesocarp of Prosopis farcta. Photo credits A-C, F, H O Bajpai and L Babu Chaudhary D CE Hughes E Zeynel Cebeci https: // commons. wikimedia. org / wiki / File: Prosopis _ farcta _ - _ Syrian _ mesquite _ 01. JPG G Eitan Ferman https: // de. wikipedia. org / wiki / Prosopis _ farcta # / media / Datei: Prosopis _ farcta, _ flower. jpg I Zeynel Cebeci https: // en. wikipedia. org / wiki / Prosopis _ farcta # / media / File: Prosopis _ farcta _ 01. JPG.

Figure 136. Distribution of Indopiptadenia based on quality-controlled digitised herbarium records. See Suppl. material 1 for the source of occurrence data.