1914I BAILEY & SINNOTT—PHYLOGENY OF ANGIOSPERMS 59 



EXPLANATION OF PLATES III-V 



Fig. i.— Transverse section of a seedling stem of Fagus, illustrating the 

 structure, development, and distribution of multiseriate rays which have not 

 suffered reduction. 



Fig. 2. — The same; young root. 



F IG - 3- — Transverse section of a vigorous young seedling stem of Quercus 

 rubra, showing multiseriate rays which radiate from each wide gap in the 

 primary elements. 



Fig. 4. — The same; less vigorous seedling stem, showing the disintegration 

 and reduction of wide rays and their recurrence in tissue which has been formed 

 under the stimulating effects of an injury. 



F IG - 5- — Transverse section of a suppressed seedling of Fagus , showing 



the arrested development of wide multiseriate rays in the first formed portion 



of the hypocotyledonary stem and their sudden recurrence after a stimulating 

 type of injury. 



Fig. 6. — Transverse section of a young root of Quercus (subgenus Lepido- 

 balanus), showing the reduction of multiseriate rays; "trails" of aggregated uni- 

 senate rays mark the former position of the wide rays; in one radius vestiges 

 of a multiseriate ray have persisted in the vicinity of the outgoing vascular 

 elements of a rootlet; in another portion of the root a stimulating type of injury 

 has recalled wide homogeneous sheets of ray parenchyma. 



F IG - 7- — Transverse section of the seedling stem of Casuarina suberosa, 

 showing the disintegration and reduction of wide rays. 



Fig. 8. — Transverse section of a peduncle of the same species, showing 

 well developed multiseriate rays. 



Fig 9. — Transverse section of a vigorous young shoot of Quercus (sub- 

 genus Erythrobalanus) , showing five depressed segments and multiseriate rays. 



Fig. 10. — Transverse section of a stunted, slow growing branch of Quercus 

 (subgenus Erythrobalanus), showing the reduction of multiseriate rays, their 

 persistence on either side of the depressed segments, and their recurrence 

 in tissue stimulated by injuries. 



Fig. 11.— Transverse section of a very vigorous young root of Castanea 

 dentata, showing the persistence of vestiges of wide rays in the vicinity of the 

 vascular elements which supply the rootlets. 



Fig. 12.— Transverse section of a shoot of Alnus, showing the persistence 

 of "trails" of uniseriate rays about the lateral leaf-traces and their recurrence 

 in traumatic tissue. 



Fig. 13. — Transverse section of a portion of a vigorous seedling stem of 

 Quercus rubra; two multiseriate rays radiate from the gaps between three 

 clusters of primary elements; X45. 



Fig. 14. — Transverse section of a portion of a less vigorous seedling stem 

 of Quercus rubra, showing the reduction and disintegration of two multiseriate 



»ys; X45. 



