Surface wax, a new taxonomic feature in Plagiochilaceae

A scanning electron microscope study of 81 species of Plagiochilaceae revealed the presence of superficial waxes on the leaves and stems of Plagiochilion mayebarae and 5 species of Plagiochilia. The waxes are not visible in the light microscope and were unknown in Plagiochilaceae. Plagiochila fuscolutea and P. longiramea (= P. sect. Fuscoluteae) are characterised by the predominant occurrence of membraneous wax platelets; Plagiochila aerea, P. rudischusteri and P. tabinensis( = P. sect. Bursatae) predominately form various types of wax rodlets. Our findings show for the first time the systematic usefulness of leaf surface waxes in the liverworts. P. tabinensis contains surface waxes in amounts of ca. 1.4% dry weight composing of steryl esters, triacylglycerols and free fatty acids.