FIG. 60. Part of cross section of stem of flax 



c, epidermis; b, hard bast; s, sieve cells; w, wood. Much magnified. After 



Tschirch 



FIG. 61 



FIG. 62 



FIG. 61. A group of hard-bast fibers 

 o, cut-off ends ; b, lengthwise section of fibers. Greatly magnified. After Tschirch 



FIG. 62. A lengthwise section of a group of spiral vessels from the stem 



of sunflower 



At the top of the figure some of the spiral threads which line the vessels are seen 



partly uncoiled. Greatly magnified. After Frank 



62 



