Karyomorphological and SEM studies in newly discovered populations of a critically endangered medicinal plant - Lilium polyphyllum D. Don ex Royle from a high altitude protected area of north-western Himalaya.

In this study, new populations of a critically endangered Himalayan herb, Lilium polyphyllum D. Don ex Royle have been reported from Chamba, Himachal Pradesh, India for the first time. Karyotypic, palynological, and spermological studies under the light microscope (LM) and scanning electron microscope (SEM) have been carried out on specimens from these populations with an aim to add more knowledge to the current database of the species. Presently studied individuals depicted a diploid (2x) chromosome count of 2n = 24, which is in confirmation with the previous reports from Kashmir Himalaya. Mitotic study showed a karyotype formula of 2n = 2x = 2m + 2sm + 4st + 16t, that is, 2 metacentric +2 submetacentric +4 acrocentric +16 telocentric chromosomes. LM and SEM observations revealed that the pollen grains are monosulcate, heteropolar, elliptical in polar view, and oblate with reticulate ornamentation. Based on the criteria of number, shape, and arrangement of columellae that form the muri, pollen grains in L. polyphyllum correspond to Martagon type. This is the first SEM based study on pollen grains and seeds of endangered Himalayan white lily. Based on the present ecological data collected we confirm the status of L. polyphyllum to be critically endangered in the study area.