A. J. Robi
Department of Botany, Kannur University, Kannur 670 002, INDIA.
Lauraceae is a lesser known pantropical family, belongs to the order Laurales which includes seven families and contains nearly 85 genera (Angiosperm Phylogeny Group III, 2009; Renner, 1999). Of the seven families in the order, three namely, Lauraceae, Monimiaceae and Hernandiaceae have been recorded from India (Hooker, 1886). The family Lauraceae comprises 2,500 to 3,000 species in about 50 genera (Van der Werff & Richter, 1996).
Laurels are distributed throughout the tropical and subtropical regions of the world, mostly in South East Asia and America. In India, the members of the family mainly occur in the Himalayas, North East, Andaman and Nicobar Islands and Western Ghats. Majority of the members are trees and shrubs, with the exception of Cassytha, an herbaceous semi-parasitic vine.
Economically, the family is very important as sources of medicine, timber, nutritious fruits, spices and perfumes. (Van der Werff, 2001). Though Lauraceae is among the floristically most important tropical woody families, the relationships within the family are inadequately studied (Gentry 1988).
Taxonomically, the family is a challenging group, mainly due to its floral complexity. Lauraceae has not been subjected to in-depth study on the taxonomy and nomenclature (Kostermans, 1983; Saldanha, 1984; Matthew, 1996; Pullaiha & Ali Moulavi, 1997; Sasidharan, 2004). The first major systematic treatment of Lauraceae on a world-wide basis were by Nees (1836) and Meissner (1864). Kostermans (1957) has classified the family, and he established a frame work for the worldwide revision.
The taxonomic revision contains nomenclatural history, morphology, ecology, analyses and systematic treatment. Herbarium specimens of all the taxa collected from different localities of South India were prepared. Photographs depicting field and floral characters were taken and illustration drawn. The specimens were critically studied, and identified with relevant literature, protologues and type specimens. The doubtful collections were compared with type specimens available in the major herbaria of the country viz., CAL, CALI, FRC, FRLH, JCB, MH, KFRI, RHT and TBGT. Information or digital images of types and non-type materials in the herbaria abroad viz., BM, E, G, G-DC, GZU, K, L, MBG NY, P, PDA and LINN were also referred. Type sheet information retrieved from JSTOR was also used for the study. The present work is the first and most comprehensive study on the taxonomy and morphology of the South Indian Lauraceae.
The novel and significant findings as well as contributions of the study are summarized below. The intensive and extensive field trips (2008–2014), critical study of vegetative and generative characters of Lauraceae members resulted in the finding of 82 indigenous and 5 cultivated taxa belonging to 13 genera, consisting 1 climber (Cassytha filiformis L.) and 86 large shrubs or trees from South India. Among them, 10 taxa are new to science.
Conservation status of all taxa was evaluated using IUCN (2001 & 2010) criteria. Actinodaphne campanulata var. campanulata, Actinodaphne lawsonii, Cinnamomum perrottetii, Cinnamomum riparium, Cryptocarya beddomei and Neolitsea fischeri are Vulnerable. Species like Actinodaphne campanulata var. obtusa, Actinodaphne salicina, Beilschmiedia wightii, Cinnamomum chemungianum, Cinnamomum filipedicellatum, Cryptocarya anamalayana, Litsea beddomei, Litsea mysorensis, Litsea nigrescens and Litsea travancorica are Endangered. Actinodaphne shendurunii and the 9 tentatively named new species viz. Alseodaphne sp.1 & 2; Beilschmiedia sp.1 & 2; Cinnamomum sp.1; Litsea sp.1 & 2; Machilus sp. 1; Neolitsea sp. 1., Cinnamomum travancoricum, and Actinodaphne lanata will come under Critically Endangered category. The family lauraceae is the most complicated family in the order laurales. Recent molecular phylogenetic studies revealed that some generic status need change. The genera namely, Litsea and Cinnamomum necessitates a comprehensive molecular study, these genera shows intricate problems in the delimitation of the taxa within them.