Holloway. — Studies in the New Zealand Species of Lycopodium. 87 



By dissecting under the microscope portions of old roots which showed 

 green patches in the cortical tissues I was able to obtain a good series of 

 developing plantlets. Certain individual cells of the cortex, which are 

 similar in appearance to the other cortical cells except that they contain 

 abundant protoplasm and chloroplasts, divide transversely (figs. 6 and 7). 

 In some cases transverse division is continued so that the original cell becomes 

 a filament several cells in length (fig. 6). In most cases, however, longi- 

 tudinal walls appear early in the cells of the filament, so that it begins at 

 its growing end to take on the form of a cell-mass (figs. 6-10). The growing 

 end soon becomes globular in shape and bends away more or less at right 

 angles from the original direction of the initial and other cortical cells, 

 evidently turning towards the upper surface of the root (figs. 7 and 10). 

 The globular growing end of the young plant becomes the basal tuberous 

 region of the plantlet of a later stage of development. In some cases it 

 grows very regularly to form an egg-shaped cell-mass, the summit of which 

 is continued as the first protophyll (fig. 13). Again, in other cases the tuber 

 grows very irregularly before the first protophyll appears (figs. 11 and 12). 



Figs. 11, 12. — Lycopodium ramulosum. Gemmae developed from cortical cells of old 



isolated rootlets. X 45. 

 Fig. 13. — Lycopodium ramulosum. Group of adventitious plantlets in different stages 



of development attached to old rootlets. X 12. 



About the stage of development attained by the plantlet shown in fig. 11 

 rhizoids first make their appearance on the tuber. From the first initiation 

 of the young plant the adjacent cells of the root give rise to a group of 

 rhizoids, showing that the developing plant is in its first stages nourished 

 from the cells of the parent root. As the plantlet increases in size it bursts 

 the outer tissue of the root, and the first protophyll is then quickly developed 

 (Plate VIII, fig. 1). The first-formed tapering portion may clearly be seen 

 on the developing plantlets (figs. 11 and 12), and may sometimes still be dis- 

 tinguished at the base of plants which show as many as three or four full- 

 sized protophylls. As the plant grows, the tuberous basal portion becomes 

 elongated in most cases by the swelling of the lower extremity of the proto- 

 phyll till it assumes a sausage-like shape, but the original end of the tuber 

 retains its first-formed somewhat irregular form. As has been noted above, 

 I have observed one or two plants in which the young developing tuber 

 had grown very irregularly so as to form one or more, distinct haustoria- 

 Like protuberances. There can be no doubt that these penetrated the 

 cortical tissues of the parent root and functioned as absorbing surfaces. 



