ISOETES JAPOJS^ICA, A. BR. 



373 



Explanation of Abbeeviations, 



eel. L 



cut. 



cut J. 



l. 



It. 



lig. 



lig.sh. 



mer. 



n. 



P 



per 



cambium. 



cellulose layer. 



cortex {ct.p. = cortical parencliyma) 



cuticle. 



cuticularized layer. 



main furrow, secondary furrow. 



leaf. 



leaf-trace. 



ligule. 



ligular sheath. 



mantle. 



meristem (primary). 



nucleus. 



parenchyma. 



periderm. 



ph.\ ph? = primary phloem^ secondary phloem 



pier, 



pr,x. 



ps,e, 



rh. 

 rJ. 



i7\ 



V. 



X. 



[ph. p. 



plcrome. 



protoxylem. 



pseudo-endodermis. 



root. 



rhizophore. 

 root-trace. 

 stem. 



phloem parenchyma). 



sieve 



x.p 



-tube, 

 tracheid. 



vesicle. 



xylem {x^ = primary xylem, x 



secondary xylem). 

 xylem parenchyma. 



EXPLANATION OE PLATES 33-40. 



Figs. ] 



Plate 33. 



3. From transverse sections of the caudex^ showing successive stages in the formation of a 



main furrow. 



a 



b 



cells without starch, probably phellogen ; 

 cells with suberized walls (= periderm). 



In all three figures the left-hand side is towards the centre of the stem. Fis:s. 1 & 2 X 220; 

 fig. 3 X 100. 



Fig. 4. Lateral view of a fairly old caudex. Nat. size 



Fig 



5. Caudex of a young plant (about two years old) viewed from below 



been removed in order to show their arrangement on the caudex. 



Some of the roots have 

 Nat. size. 



Fig. 6. Lateral view of the same specimen. The leaves and roots have been completely removed 



Nat. size. 

 Fig. 7. A median longitudinal section of a plant about four years old. 



X 1-5 



a 



h 



present season's growth ; 

 groups of stretched cortical cells. 



Fig. 8. Central portion of the same section magnified five diameters. 



Fig. 9 



Plate 34. 



Longitudinal section through the caudex represented in figs. 5 & 6. The plane of the section 



/S 



X 2-3. 



Fig. 10. Apical portion of the same section (diagrammatic). Since this section is not strictly median, 



it does not pass through the actual apex of the stem. Note at x the early dififerentiatioa 



of the stelar tracheids. 



x45. 



