Observations on the Phenology and Reproductive Success of the Critically Endangered Nervilia nipponica (Orchidaceae) in Kochi Prefecture, Japan

Nervilia ntpponica it crilically endangered and poorly known tbroughout ita range jo Japan. Jo order to illuminate detalis of the apecies' life hiatory, observationa 00 Ihe phenology and reproductive auccesa of two large populaliona jo Kochi Prefecture were made from 2003-2004. Pattems of emergence were comparable and individuala jo both populationa exhibited a highly aynchronoua phenology. The average individual flowering period latied 12.3 and 11.0 daya reapectively al the jwo titea, and dehiacence of fruil capaulea occurred 25.6 and 25.3 daya afier flowering. Only 34.2% and 28.4% of planta al Ihe iwo sitea tuccetafully flowered, bui ralea of seed tel were 38.2% and 52.4% deapite lhe virtual abaence of a nectar reward and Ihe lack of polleo vectora, probably indicative of aelf-pollination. The failure of individuala marked jo 2003 lo re-emerge, aa well aa Ihe appearance of unmarked individuala jo 2004, auggeata thai Ihe apecies has a capacity for dormaney and/or rapid propagation vja Ihe ttaber. Evjdence for Ihe latier ja provjded by the excavation of 89 tubera from 58 individuala, repreaenting an average rate of increase of 1.5 per individual per year. Recommendationa are made for ongoing atudies towarda Ihe development of a conaervation atrategy for Ihe apecies.