Leaf Scale Traces in Corsican Pine

Discusses briefly a feature observed during an investigationof the structure of leading shoots of 1-year-old Corsican pine(Pinus nigra var. calabrica, Loudon). The feature, which doesnot appear to have been described previously in literature hasbeen tentatively called a ‘Leaf scale trace’.     

A NEW METHOD OF MEASURING TRACHEID LENGTH

The image of a tangential microscope section is projected onto a surface on which two parallel lines are drawn at a knowndistance apart and at right angles to the long axis of the tracheids.The number of cell tips occurring between the lines in a predeterminednumber of contiguous cells is counted. Values are then substitutedin the following relationship: Mean tracheid length=Number of cells ? distance between lines/numbersof cell tips The method is faster than the usual maceration technique, butits greatest advantage is the accuracy with which samples canbe located.