I 4 8 



ROUND THE YEAR 



all sure that this is the real purpose of the ligule 

 water does not easily enter a narrow, air-filled space. 



FIG. 47. Haulm of Oat. a, base of haulm, showing knots and leaf-sheaths ; 

 /', roots of ditto piercing the leaf-sheaths ; c, section through a knot and leaf-sheath. 



When the haulm is young, it is solid, and com- 

 pletely filled by soft cellular tissue. The sections 



