THE STONEWORTS. 81 



I PLATE XX. 



THE STONEWOKTS. 



FIG. I. An entire actively-growing plant of Chara.* 



Growth at the summit was making good disintegration and death at the base, 

 resulting in a separation between the main and the oldest lateral axes, as figured. 

 The rhizoids are indicated for but one node. Nat. size. 



FIG. II. The same, from internode 5 6 upwards. 



The appendages of whorls 2 to 4 were slightly displaced, to render visible the apex. 

 * 8. 



One segment of the descending cortical lobe has, in the case of two internodes and of 

 two lateral axes, been shaded darkly. The pails lettered n.c. represent one cortical node. 



Only one lateral bud is drawn, ax'., and no note is taken of the fruits. 



FIG. III. Median longitudinal section through the terminal bud of a similar plant. 



The growing apices are left white, and the nodal and cortical elements are shaded 

 darkly. D. 3. Osmic acid and alcohol. See Parker (137). 



The arrows indicate the directions of growth of the cortex. 



The nuclei of the old cells are not drawn, being in the condition described by Stras- 

 burger (142) as fragmentary. See also Johow (135). 



FIGS. IV. to VII. Four teased preparations of dividing apical cells, preserved as for 

 Fig. III. 



As drawn, they represent in order four successive phases in the developmental history 

 of the growing apex. 



The sub-apical (segmental) cell is, in Fig. VI., and its products are in Fig. VII., shaded 

 darkly. D. 3. 



FIG. VIII. A fertile leaf of Nitella, bearing both male and female organs. 

 Seen from the side. A. 3. 



FIG. IX. A similar leaf, bearing female organs alone. Seen from above. A. 3. 



* A synopsis of British Characeoi will be found in Groves (184). 



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