Silicification of Branched Cells in the Leaves of Nardus stricta L.

Abstract

ATTENTION has been directed¹ to the presence of certain peculiar branched rods of opaline silica in the leaves of Nardus stricta and in the soils on which this species grows. Although transverse sections of leaves of N. stricta figured by Grob² and Hegi³ show what are apparently the minute hat-like opals which we have detected even in the very young leaves, we have found no reference depicting or describing the branched rods which we detect in surface preparations of older leaves after rendering them transparent, for example, by controlled treatment with chromic acid (Fig. 1). The branched cells which secrete these bodies, although not present in the seedling leaves, develop later on the well-marked ribs of the upper surface (Figs. 2 and 3), and their protruding portions can be identified with what have been described as asperities⁴ or papillæ². The protrusions tend to be longest near the crest of the rib, diminishing laterally to give every gradation from well-branched to unbranched long cells (Figs. 4 and 5).