Acanthus volubilis

Overview

Voucher-backed collections and regional floras record Acanthus volubilis as a mangrove plant. South Andaman records place it near the high-tide line and give flowering in March–April and fruiting in May–June; a 2024 Singapore survey lists 15 field collections. No quantitative salt treatment or population root-zone salinity data are available for this species. [S1, S3, S5, S6]

Names and classification

POWO accepts Acanthus volubilis Wall. as a distinct species. Acanthus ilicifolius var. volubilis and Dilivaria volubilis are related synonyms; historical records should be assessed against the material actually collected by each author. [S1, S3]

Historical names involve both A. volubilis and A. ilicifolius; the identity of material in older studies depends on the taxonomic scope and identification information used by the authors. [S1, S3]

Morphology and identification

A mangrove climber or scrambling shrub; flowering and fruiting vouchers help with identification. Some older Indian sources misapplied the name to unarmed A. ilicifolius, so locality and the absence of spines alone are insufficient for identification. [S1, S3, S6]

Distribution, habitat and phenology

Feng et al. (2024) list 15 field collections from Sungei Buloh Wetland Reserve, Singapore. Ragavan et al. (2015) report wild populations at Shoal Bay Creek and Jirkatang in South Andaman, on the landward side of mangroves near the high-tide line and inundated by spring tides; flowering and fruiting vouchers are PBL30967 and PBL30968. The NParks local flora adds a record from the landward mangrove zone in Singapore. [S1, S3, S5, S6]

The South Andaman account records flowering in March–April and fruiting in May–June; these are local phenology observations. [S6]

Salinity in natural habitats

Field collections, voucher specimens, and the Singapore flora support a native mangrove association. Population root-zone salinity and a controlled salt treatment for this species have not been reported. [S1, S3, S5, S6]

Salinity studies

The sources assembled here focus on taxonomy, voucher collections, and habitat; they report no quantitative salt treatment or salinity-related growth endpoint for this species.

Reported mechanisms and ecological adaptations

Available sources establish mangrove occurrence and taxonomic identity, but do not report a quantitative physiological or molecular mechanism for this species. [S1, S3, S6]

Conclusions and evidence gaps

The 2015 flowering and fruiting vouchers PBL30967 and PBL30968, together with 2024 Singapore collections, document A. volubilis in mangroves. Thothathri (1962) reported A. volubilis from Great Nicobar, but Ragavan et al. (2015) examined the specimen and identified it as a spineless form of A. ilicifolius; that record therefore does not document A. volubilis on Nicobar. Other records under older names still require voucher checks. [S1, S2, S3, S4, S5, S6]