The scientific community is buzzing with the discovery of a new genus of a parasitic flowering plant from the Nicobar group of islands. This discovery, while interesting in its own right, also highlights the ecological significance of the region, as four other non-parasitic plant genera – Nicobariodendron (Hippocrateaceae), Pseudodiplospora (Rubiaceae), Pubistylis (Rubiaceae), and Sphyranthera (Euphorbiaceae) – have also been found here earlier.
About Parasitic Plants
Parasitic plants are unique in the plant kingdom. Unlike their self-sustaining counterparts, these organisms derive all or part of their nutrition from another plant, known as the host. Far from being beneficial, this relationship is often harmful to the host plant.
The characteristic feature of parasitic plants is the haustorium, a special organ that infiltrates the host and establishes a vascular union between the two plants. It’s important to distinguish parasitic plants from others such as climbing vines, lianas, epiphytes, and aerophytes. While these plants may rely on other plants for physical support, they are not considered parasitic because they don’t consume the water or nutrients of their host.
Spotlight on Septemeranthus
The newly discovered genus, fittingly named Septemeranthus, thrives on the plant species Horsfieldiaglabra (Blume) Warb. Interestingly, while it partially depends on this host for sustenance, Septemeranthus also has leaves capable of photosynthesis, making it a hemi-parasite.
This genus is exclusive to the Nicobar group of islands. Its name “Septemeranthus” is derived from the Latin word ‘septem’, translating to ‘seven’, indicative of the floral arrangement the plant boasts. It falls under the family Loranthaceae, a type of hemi-parasite found under the sandalwood order Santalales. This family is widely significant due to its members being partially dependent on their host plants for nutrition.
Distinctive Features of Septemeranthus
Septemeranthus goes beyond the ordinary with its distinguishing features. Its leaves are heart-shaped, ending in an unusually long tip, and its ovary, fruit, and seeds take on an ‘urceolate’ or earthen pot-like shape. Another noteworthy feature of this genus is its root structure. The roots are modified to spread on the stem of the tree and anchored within the tree bark, marking a secure hold on its host.
Hemi-Parasites: A Closer Look
Commonly known as mistletoes, hemi-parasites make up 18 families with 160 genera and over 2,200 species. Their survival hinges on the existence of a host tree or shrub. They enjoy a global distribution in both tropical and temperate habitats and have evolved around five times in order.
Critically, they hold importance in forest ecology, pathology, and medicine. Additionally, they play a pivotal role in supporting the food chain as they serve as food for frugivorous (fruit-eating) birds. Through these contributions, hemi-parasites like Septemeranthus underline the complex dynamics of our ecosystem.
While the discovery of Septemeranthus contributes to our understanding of nature’s diversity, it is also a reminder of the ecological significance of the Nicobar group of islands and the need for their protection.
