876 



ON ISOETES JAPONICA, A. BE. 



Fi"*. 71- Surface view of the growing-point of the stem of Isoetes japoiiica. x 320. 



Drawn from a thick hand-section cleared with ' Eau de Javelle/ 

 Fi<'. 73. Surface view of the growing-point of the stem of Isoetes lacustris. X 320 



Drawn from a microtomed section. 



Plate 40. 



Fig. 73. Longitudinal section through the apex of a dichotomizing root, x 50. 



Fig. 74. Secondary phloem from a transverse section of an old stem. X 200. Note sieve-fields and 



deposits of callus. 

 Fig. 75. Median longitudinal section through the stele of a very young plant The plane of this 



+ 



section is at right angles to that of a main furrow, x 165. 

 Fig. 76. Secondary phloem from a transverse section of an old stem, x 190. Note deposits of callus. 

 Fig. 77. Transverse section through the lower half of one of the lobes of the rhizophore-stele. This 



section is cut near the apex of the lobe. X 165. 

 Note how the cambium (seen above and below) is interrupted by the apical meristem {mer.) 



of the rhizophore. The arrow points towards the lower surface of the stelar lobe. 

 Fig. 78. Transverse section of the stele of an old stem, x 23- 



Fig. 79, Transverse section of the stele in the transitional region between stem and rhizophore. x 45. 

 Fig. 80. Transverse section of the stele of the rhizophore. X 40. 



