Piece of a stem of Soft Maple, of a year old, cut crosswise and lengthwise.
Asa Gray The Elements of Botany for Beginners and for Schools (New York, Cincinnati, Chicago: American Book Co., 1887)
1507×2400, 923.5 KiB
642×1024, 133.5 KiB
401×640, 66.3 KiB
200×320, 20.7 KiB