Notes on the Reproductive Biology, Population Ecology, and Conservation of the Critically Endangered Sanjappa cynometroides (Leguminosae: Caesalpinioideae) from India
Gopika Suresh (St Teresas College, Kerala, India)
Krishnaraj M.V. (Baselius College, Kerala, India)
Sanjappa cynometroides (Bedd.) E.R.Souza & Krishnaraj (mimosoid clade, Caesalpinioideae) is a monotypic genus of small legume trees narrowly endemic to Kerala in southern India. The taxonomic identity of this enigmatic taxon, previously placed in the genus Calliandra, was recently resolved using morphological and molecular phylogenetic analyses by Souza et al. (2016) who described the genus Sanjappa to account for its isolated phylogenetic position. However, despite these taxonomic advances and the conservation importance of the genus, data on the reproductive biology and ecology of Sanjappa, that could underpin conservation measures, are still lacking.
This poorly-known legume tree, at one time thought to be extinct, is currently known from just two populations, in Kallar and Rosemala, in the southern portion of Kerala State in the Western Ghats of southern India. Sanjappa is thus globally rare and was categorized as Critically Endangered by Souza et al. (2016). Field observations show that both of these populations are found growing near streams, that the number of individuals is fewer than 50, and that there is low fruit set and limited seedling regeneration even though there are 4–6 seeds per fruit. The reasons for poor regeneration in the field are unknown, but heavy fruit predation has been observed. The nearby rubber plantation and local community use the branches of this tree for making household utensils without knowledge of its taxonomic or conservation significance, adversely affecting the populations. The flowering and fruiting time of Sanjappa cynometroides is from August to January (Souza et al. 2016). Floral ontogeny of Sanjappa is still lacking.
A new study of the reproductive biology and population ecology of Sanjappa is being undertaken by doctoral student Gopika Suresh with a programme of field observations during 2022.
Reference: Souza, E.R., Krishnaraj, M.V. and de Queiroz, L.P. (2016) Sanjappa, a new genus in the tribe Ingeae (Leguminosae, Mimosoideae) from India. Rheedea 26(1): 1–12.
Sanjappa cynometroides (Bedd.) E.R.Souza & Krishnaraj (Caesalpinioideae), fruit, photo by authors.