An annual ring consists of .........

The secondary growth in the stem of $Cycas$ is brought about by:

Tyloses,an outgrowth from ray or axial parenchyma cells into the lumen of a vessel,which partially or completely blocks the cavity,are present in:

The position of xylem in secondary xylem is:

In old trees,the greater part of secondary xylem is dark brown due to the

Diffuse-porous wood is a characteristic of plants found in which region?