A plant that makes a cameo appearance when the rain subsides

Thismia sahyadrica found in Idukki district.— Photo: Special Arrangement  

Plant taxonomists have found a new species of mycoheterotrophic plant in the Idukki forests of Kerala. The plant species makes a cameo appearance after a heavy spell of monsoon showers.

The species has been named Thismia sahyadrica and it is the first report from the mainland of India, according to scientists.

A mycoheterotrophic plant is the one that depends on mycorrhizal fungus, with which it establishes a symbiotic relationship, for carbon and nutrient supply. The plants resort to parasitism as they lack chlorophyll and cannot produce food on their own through photosynthesis.

It was during a floristic exploration in the Idukki district of Kerala, which falls under the Anamalai phyto-geographical region of Western Ghats, that the scientists stumbled upon the species. “It was found surviving in the humus-rich soil of medium elevation evergreen forests,” said P. Sujanapal, a plant taxonomist of the Kerala Forest Research Institute (KFRI), Peechi, Thrissur.

The exploration team, which consisted of A.J. Robi of the Department of Botany, Bishop Abraham Memorial College, Pathanamthitta, and K.J. Dantas and M. Sumod of the KFRI, counted 35 flowering individual plants within one area of the forest. The researchers say that phylogenic studies related to the evolutionary and phyto-geographical affinities of the species with its cousins in other parts of the world needs to be carried out as its major distribution is found in the East Asian region of Asia and other continents.

Though the new species has similarities to the Thismia rodwayi of Australia and New Zealand in general habit and flowers, it stands out with its long stem, obconical shape and colour of the perianth tube. According to the researchers, the newly described species is a non-photosynthetic ephemeral, which emerges briefly to flower and fruit after a period of heavy showers during the monsoon, especially in the months of June and July.

“Observations on the microhabitat and distribution pattern indicated that the new taxon is restricted to undisturbed and morphologically highly unique, humus-rich soil substratum under the dense shade of evergreen forests with associations of macro and micro biota”.

Little is known about its habitat, distribution, reproductive biology and lifecycle. A detailed ecological evaluation is essential for understanding the structure and associations of the plants with its complex ecosystem, says Dr. Sujanapal.

The plant has qualified to be included in the Critically Endangered category of the IUCN Red List Categories and Criteria of endangered flora and fauna.