Bryophytes, which include mosses, are known as non-vascular plants. Although mosses lack the vascular tissues xylem and phloem, many mosses posses water-conducting cells called hydroids and food-conducting cells called leptoids. Unlike the xylem of vascular plants, the hydroids found in mosses are not lignified. Many mosses have leaves only a single cell-layer thick. A clear … Continue reading Polytrichum leaf cross section