Distribution, morphology, and phenology of Piper acutistigmum C. DC. – an endemic species of the Eastern Himalayan region

Abstract

Piper acutistigmum C. DC. is an endemic species of the Eastern Himalayan region found in northeast India with the adjacent country Myanmar. A study was conducted to examine the distribution, morphology, and phenology of the species, which is an important step towards its conservation. Field surveys were conducted to locate the population, and observations were made on selected plants from three distinct locations. The study revealed that the species is mostly found in the foothills of Arunachal Pradesh and its bordering areas in Assam. The orthotropic and plagiotropic branches show distinct differences in terms of leaf size and shape, petiole, and internodal length. The average sizes of the leaves were 10 × 6 cm and 21.5 × 12.5 cm; petiole length was 3.7 cm and 2.25 cm and internodal length was 17.5 and 6.5 cm in orthotropic and plagiotropic branches, respectively. Leaf flushing occurs between the March and April months, more or less in synchronization with the emergence of the spike bud. The species starts flowering from April until the end of May. The fruiting spikes are observed from July to December. Sterile vines are most dominant in a population with a few fertile (male and female) individuals. The existing natural population is under threat from various developmental activities in and around their habitat and needs immediate attention for conservation.