An overview of Lejeuneaceae (Marchantiophyta) in India with a comprehensive note on the status of the family in the state Assam

Abstract

Lejeuneaceae is one of the dominant and advanced families of the group Marchantiophyta (liverwort) of bryophytes which prefers to grow in humid forests of topical-subtropical regions. India, owing to its tropical climate, vast range of topography and high percentage of forest cover, harbours a significant percentage of the Lejeuneaceae members represented by 25 genera and 233 species (including infraspecific taxa) (Sing & al., 2016). Lejeuneaceae is the largest liverwort family of India and the taxa account for about 26% of the total Marchantiophyta flora of the country. Within the family, genus Cololejeunea is the largest with 56 species followed by genus Lejeunea with 50 species. Some other prolific genera are Cheilolejeunea (21 spp), Drepanolejeunea (18 spp.), Lopholejeunea (15 spp.) and Leptolejeunea (12 spp.). Six genera are represented by single species each viz. Frullanoides, Lepidolejeunea, Myriocoleopsis, Otelejeunea, Ptychanthus and Tuzibeanthus. Out of the total taxa of Lejeuneaceae reported from India, 44 species are found as endemic to the country. Among these, genera Lejeunea and Cololejeunea contribute a large percentage with 14 and nine endemic species respectively. Assam, a forest dominated state in North-eastern India lying in the rain shadow of Himalayan ranges and situated amidst the Indo-Burma Biodiversity Hotspot, cradles a good number of taxa from the family with 61 species under 13 genera. Here too, Cololejeunea has been found to be the dominant genus with 24 taxa. Some other dominant genera are Lejeunea (8 spp.), Leptolejeunea (6 spp.) and Cheilolejeunea (6 spp.). Genera represented by single species in the state are Caudalejeunea, Colura and Ptychanthus. Seven taxa from the family, which are endemic to India, have been found to occur within the state. Three taxa, viz. Cololejeunea denticulata, C. inflata and Drepanolejeunea spicata have been reported to occur only in the state Assam within the Indian territory. Although members of the family use a wide range of substrates for their growth, but, mostly they favour barks (corticolous) and/or leaves (epiphyllous) of other higher plants and thus, constitute dominant composition of epiphytic liverworts. In the state Assam, heavy rainfall, high percentage of humidity and dense, moist forests have provided a suitable microclimate for growth of the epiphytes. It has been found from the present study that about 75% of taxa from Lejeuneaceae in the state are epiphytic. Some common host plants of the epiphytic Lejeuneaceae are various ferns, Bambusa sp., Ficus sp., Shorea robusta, Morus sp., Zingiber sp., etc. It has been observed that corticolous taxa grow mostly on plants having rough stem bark for ease of anchorage of the rhizoids.

Keywords: Lejeuneaceae, India, Assam

Reference: Singh, D. K., S. K. Singh and D. Singh. 2016. Liverworts and hornworts of India – An annotated checklist. Botanical Survey of India, Kolkata. pp. 1 – 439.