Arisaema tortuosum subsp. sivadasanii
Arisaema tortuosum subsp. sivadasanii is allied to A. tortuosum var. tortuosum and A. tortuosum var. neglectum (all belong to section Tortuosa). A comparative account of morphological and pollen characters is given in Table 2.
This subspecies has an area of occupancy estimated to be less than 20,000 km2, with a severely fragmented population at fewer than 10 locations. The population size is estimated to be fewer than 10,000 mature individuals, and no subpopulation is estimated to contain more than 1000 mature individuals. This population is currently under severe threat due to decline in quality of habitat (habitat conversion and road widening) and forest management operations like weeding. If such threats continue, the population size may be reduced to a greater extent in the near future. Therefore, after applying IUCN (2001) criteria, the subspecies is categorized as Vulnerable (VU).
This subspecies is so far known to be endemic to the North Western Ghats, from Chandoli Wildlife Sanctuary in Maharashtra to Molem National Park in Goa State.
This subspecies grows along roadsides in the shade of semi-evergreen forests in association with Allophylus cobbe (L.) Raeuschel, Arisaema sahyadricum, A. tortuosum var. tortuosum, Dimorphocalyx ramiflorus (J. Graham) M. R. Almeida, Gynura biflora (Burman f.) Merrill, Luvunga eleutherandra Dalzell, and Mallotus stenanthus Müller Argoviensis.