ISOiiTES JAPONXCA, A. BR. 



375 



Fig. 41. Part of a transverse section of a leaf showing the large clear cells abutting on a lacuna 



X 285. 



r 



Fig. 42, Endodermis-like cells surrounding the glossopodium. X 220. 



Plate 37. 



Fig. 43. Sieve-tubes from a leaf-trace embedded in tlie cortex, x 350. Note deposition of callus 



on the walls. 



* 



Fig. 44. Sieve-tubes from the vascular bundle in a leaf. X 450. 



Fig. 45. Sieve-tube from the vascular bundle in a leaf of Isoctes lacustris. X 450. 



. 46-48. Series of transverse sections of the vascular bundle of a young leaf. All x 285. 



Fig. 46 is drawn from a section from the middle region of the leaf ; 



Fig. 47 is drawn from a section at some distance from the glossopodium ; 



Fig. 48 is drawn from a section just above the glossopodium. 

 Fig. 49. Longitudinal section of the central canal of a leaf, x 450. Note the remains of the lignificd 



bars of the end wall. 

 Fig. 50. A complete end wall of a central canal in surface view, x 1000. Note the lignified reticulum 



and the middle lamella seen through the pits. 

 (From a very young leaf.) 

 Fig. 51. Tracheids of a leaf-bundle, showing the very oblique terminal walls, x 2)^5. 

 Fie:s. 52 & 53. Young leaves of Isoetes lacustris from the centre of a leaf-rosette, showing vaginae of the 



older leaf, completely enveloping the younger leaf, x 1-5. 

 Fig. 54. Longitudinal section of an old leaf-trace embedded in the cortex. X 100. 



Between the tracheids notice the parenchymatous cells, several of which have recently under- 



gone division. 



Plate 38. 



Figs. 55-59. Successive series of transverse sections of an old caudex : 



Fig. 55 is cut just above the apical meristera, while 

 Fig. 59 is cut very near the base of the caudex. Slightly magnified. 



Fig. 60. Cell from near the periphery of the primary cortex. X 500. The starch-grains have dis- 

 appeared, leaving alveolar protoplasm to which numerous small proteid granules are attached. 



Fig. 61. Cell of the periderm with mycorrhiza. X 500. Note intercalary and ternanal vesicles. 



Fig. 62. Part of a transverse section of the stem of Isoetes lacustris. x 200. 



Fig. 68. Part of a longitudinal section of the rhizophore showing apical region of rhizophore stele. 



X 160. 



Fi-. 64. Part of a transverse section of the stem showing the peripheral tissues of the stem-stele 



X 280. 



Plate 39. 



Med 



All X 320 



Fio-. 65. An old plant of/, lacvstris. 



Fig. CS. A very young plant of /. lacustris. 



Fig. ()7, An old plant of /. Hystrtx. 



Fig. 68. An old plant of /. relata. 



Fig. 69. An old plant o{ I. jajwnica. 



Fi"-. 70. A very young plant of I.Jojiunica. 



SECOND SERIES. —BOTA XV, VOL. VIII. 



3 



