Ultramicromorphological observation of <i>Usnea longissima</i> Ach.

Abstract

The Usnea longissima Ach. grew as an epiphyte on Abies georgei and was collected at an altitude of 3640 m above sea level from the Pudacuo National Park in the Shangri-La County of the Diqing Tibetan Autonomous Prefecture in the Yunnan Province of China. Scanning electron microscopy revealed the ultramicro-organisation of the U. longissima. We observed that the interior of the specimen contained a large amount of cubic and needle-like secretions; images of the cross-section of the central axis show many densely distributed holes, and the longitudinal section of the central axis revealed many vessellike structures, similar to vessels in plants; some hyphae specialised into ring-shaped. These structures have not been reported even in other Usnea. This study gives us more comprehensive understanding of the structure and function of lichens.

Key words: Usnea longissima Ach., ultramicromorphological observation, scanning electron microscopy.