EXPLANATION OF THE FIGURES. 



PLATE I. 



Fig. i. Germinating acorn of Quercus incana. (), the short shoot of the young 

 seedling bearing small scale-like leaves (i) (V). (c), the primary root 

 which here becomes a vigorous tap-root, (e) (#), the secondary lateral 

 roots. (d\ the petioles of the cotyledons. The latter in this case are 

 thick and fleshy and remain inside the acorn, below the ground, in 

 germination. 



2. Seedling of Quercus incana with the cotyledons (e) removed from the 

 acorn, otherwise lettering as before 



3. Young wheat plant, (#). wheat-grain from which the plant has sprung 

 and which contains the single cotyledon ; (d), stem bearing green leaves 

 (') > (^) an d ( c ) roots. In this case there is no vigorous primary root 

 forming a tap-root, and a number of roots of approximately equal vigour 

 (&) (3). are found springing from the base of the stem (rf>. Vigorous 

 young adventitious roots (c) (c) have also subsequently developed 

 higher on the stem (d), just below the green leaves. The active roots 

 and their branches are seen to have particles of soil clinging to them 

 which are adhering firmly to the living roots-hairs, but the elongating 

 tips of the roots (/) (/) have no root-hairs, and are free of foil 

 particles, as are also most of the older roots (<5) (<5) and their branches, 

 their root-hairs having died off, and they themselves having ceased to 

 grow. 



4. Base of a stem of Sugarcane showing adventitious roots (a) (a) springing 

 from the stem ; (J), a bud. 



All the figures X |. 



