1920] CRIBBS—TODEA BARBARA 293 



6. Jeffrey, E. C, The morphology of the central cylinder in vascular plants. 



Rept. Brit. Ass. Adv. Sci. Toronto. 1897. 



7- ? The anatomy of woody plants. 191 7 (pp. 286-291). 



8. Kidston, R., and Gwynne-Vaughan, D. T., On the fossil Osmundaceae. 



Trans. Roy. Soc. Edin. 46:213-232. pi. 2. 1908. 



9- ', On the fossil Osmundaceae. Trans. Roy. Soc. Edin. 46:651-668. 



pis. 1-8. 1909. 



o. Seward, A. C, and Ford, S. O., The anatomy of Todea, with notes on 

 the geological history of the Osmundaceae. Trans. Linn. Soc. London II. 



260. pis. 27- jo. 1903 

 :, E. W.. Foliar eraDs in 



pis. ii y 12. 1910. 



Ann. Botany 24: 107-118. 



12. Van Tieghem, Ph., Traite de Botanique. 2: 1891 (p. 1373). 



EXPLANATION OF PLATES XXIII-XXVI 



PLATE XXIII 



Fig. 1. — Transverse section of stele between third and fourth traces, 



showing extensive parenchyma pocket and periclinal divisions of pericycle; 

 X300. 



Fig. 2. — Stele with tenth trace and seventh root; storage parenchyma in 

 xylem sheath opposite trace, and three xylem parenchyma cells; X88. 



Fig. 3. — Transverse section of stele and seventh root; absence of storage in 

 endodermis and pericycle opposite trace; gaps of sixth and seventh leaves; 

 extensive pericycle development opposite sixth trace; X138. 



Fig. 4. — Mesarch grouping of xylem elements in petiole of third leaf, 

 3 mm. above separation from stele; X118. 



Fig. 5. — Transverse section of stele and first trace, showing early phloem 

 cells and paucity of extra-xylar elements in stelar cylinder; X58. 



PLATE XXIV 



Figs. 6-24 inclusive, X40 diameter. 



Fig. 6. — Foot attachment and lateral embayment of parenchyma. 



Fig. 7. — First trace and grooving of xylem opposite. 



Fig. 8. — Xylem with two parenchyma elements included. 



Fig. 9. — Separation of second trace and grooving of xylem. 



Figs. 10, 11. — Separation of third trace from stele. 



Fig. 12. — Cleavage of protostele into two strands. 



Fig. 13. — Fourth trace being isolated from strand to right. 



Figs. 14-16. — Embayment and inclosure of parenchyma elements pre- 

 liminary to detachment of fifth trace. 



. Fig. 17. — Connection of parenchyma of preceding figure with that of 

 xylem sheath at time of separation of fifth trace. 



Fig. 18. — Solid protostele above fifth trace; first root detached immediately 

 below this level at lower left. 



* 



Fig. 19. — Second cleavage of protostele, with seventh trace to right. 



