Frerea indica Dalz. an Endangered Palaeoendemic Moving Towards Extinction: an Attempt at ex situ Conservation
Volume 2 Number 7 - December 1996
Mamgain, S.K., Goel, A.K., Sharma, S.C.
The genus Frerea (Asclepiadaceae) is a palaeoendemic monotypic genus, endemic to the Western Ghats.This species is restricted to a very small population in the Junnar hill forest of Western Ghats. There is only one population surviving with a very limited number of individuals (Jain, S.K. & A.R.K. Sastry, 1980. Threatened plants of India: A State-of-the-Art Report. BSI & MAB, New Delhi). Recently, it has been reported from the Satara District in Maharashtra (Kumbojkar, M.S, D.K. Kulkarni & D.S. Nipunage, 1993. Report on a New Locality of Endemic Frerea indica Dalz. Ind Journ. Forest. 16(1): 85-86).
According to past inventories and and herbaria records it occurred in the Shivnar hill forest and the Mahabaleswar and Purandhar hills of Maharashtra, India. No data about its occurrence in these ranges have been recorded in recent times.However, these habitats have been denuded and eroded extensively in the last few decades.
It usually grows on exposed, wet and vertical rocky faces, at an altitude of about 1,000 m. It was first described by Dalzell in 1865 from the Junnar hills in the Pune District of Maharashtra, India. It is a perennial herb with fleshy, succulent, glabrous, trailing or pendulous stems, flowering from August to September. Leaves are opposite, oblong, obtuse or subacute, fleshy, sub-sessile. Flowers are axillary, solitary or in pairs. The corolla is purple with a pale yellow, with irregularly shaped spots in the centre of each lobe.The corona is purple, anthers are red and the seeds comose.
This palaeoendemic genus is on the verge of extinction due to the loss, destruction and shrinkage of its habitat and inefficiency of the complex pollinating mechanism, largely due to lack of specific pollinators. It flowers poorly and sets little seed. Even after more than a century after its discovery and its adaptability to the extreme soil conditions, it has not succeeded in spreading in the wild or in to other similar kind of habitats.
The reproduction of this extremely interesting taxon has evolutionary significance.It has an efficient seed dispersal strategy by having comose seeds. The poor fruit set may be due to a complicated pollinia translator mechanism which depends on the visit of an insect pollinator. In the process of evolution this taxon has either lost its original pollinators and/or has not been successful in attracting a new pollination agent. Nevertheless this species has a remarkable capacity to withstand drought by shedding its leaves and further reducing the transpiration surface by developing the stem to consist of thick succulent knots with silver grey outer surface for sunlight deflection.
The destruction of its natural habitat, coupled with poor seed set threatens its survival as it moves towards extinction. The wild population of this taxon has been reduced to a very critical number.It is reported that local inhabitants eat the succulent stems and it has become endangered to such an extent that it was felt appropriate to include it in the plant list of CITES which regulates trade in the species. It has also been included in the Red Data Book of Indian Plants as endangered (E).
Ex situ Conservation
Keeping in mind the urgency of conserving this taxon, an effort to conserve it ex situ by the Botanic Garden at NBRI, Lucknow, India. Efforts are continued to multiply the plant after simulating the required habitat conditions. Seed set has not been found in the wild population and so far the plants of this taxon in our botanic garden have also not produced seeds. During our studies, propagation by stem cuttings have been successful.
This research has been carried out with the support of Dr P.V.Sane, Director NBRI and the Ministry of Environment & Forests, New Delhi for funding under the project "Ex situ conservation of endemic, rare, threatened and endangered plant species of subtropical regions of India."