RADIATING AND CONCENTRIC ARRANGEMENTS 



PLATE XXII 



39 



B 



Fm. 1. 







Flf4.12. 



Fir,. 3. 



Plate xxii. illustrates radiating and concentric arrangements in the oak, fir tree, and fungus. 



Fig. 1.— a. Transverse section of .stem of oak, showing radiation and concentric rings of growth, a, Pith nr central portion of 

 stem ; b, c, d, e, concentric woody formation.s indicating that the nak is six years old. The bark also consists of six layers. 



B. Portion of transverse section of stem of fir tree, illustrating radiation and rings of growtli. In this case the fir is three >ears 

 old, as indicated by the numerals 1, 2, 3 (after J. H. Balfour). 



Fig. 2. — Portion of transverse section of old oak, sliowing radiation and concentric rings of (;rowth. From fine photograph 

 presented to the Author liy Mr. E. A. Robertson. 



Fig. 3. — Fungus {Hexagonia glahra), displaying radiation and concentric rings of growth (Micro-Dictionary). 



PLATE XXIII 



Plate xxiii. illustrates radiating and concentric arrangements in the pine-apple, echinus, radiolarian, diatom, 

 haliomma, and xiphacantha. 



Fig. 1. — Transverse section of fresh pine-apple, showing radiating and concentric arrangements, a, Core or central part of apple, 

 concentric in its nature ; h, concentric part outside core ; c, d, e, radiating portions of pine-apple. Drawn from fresh specimen by 

 C. Berjeau for the Author. 



Pig. 2. — Transverse section of spine of echinoide, revealing a radiating and concentric arrangement, a, Core or central portion ; 

 6, concentric rings ; c, d, e, radiating parts of spine (after Griffitli and Henfrey). Greatly resembles transverse section of stem of tree 



