Spiral Ducts Small 184×320 Medium 369×640 Large 590×1024 Download Tiff Original 1382×2400 | (764.6 KB) Description Scalariform ducts of a Fern; part of a bundle, prismatic by pressure. Keywords Botany, Cells, plants, vessels Galleries Ferns Source: Asa Gray The Elements of Botany for Beginners and for Schools (New York, Cincinnati, Chicago: American Book Co., 1887) Courtesy the private collection of Roy Winkelman
