— 60 - 



protonema was not as vigorous as in the control experiment. 

 Figure 58 shows where the original spore cell has started 

 to form a Lud by the insertion of an oblique crosswall; 

 further than this however no indication of bud formation was 

 noted. The cultures in the dark produced protonema of con- 

 siderable size and vigor, but the vigor of growth was mar- 

 ke dly below the same cultures in the light. The protonema 

 were perfectly free from Chlorophyll and the considerable size 

 attained shows that to a certain extent they are able to 

 adapt themselves to a saprophytic mode of nourishment. 



In the light the main protonema axes were directed 

 parallel to the incident lays of light and grew either in or 

 on the surface of the culture medium. The secondary branches 

 grew erect from the prostrate axes, and directed themselyes 

 towards the light at an angle of about 45°, thus exhibiting 

 a marked positive heliotropism. Sachs 1 has already referred 

 to the so-called dorsiventrality of Funaria protonema. In 

 the dark the main axes were without any definite direction, 

 while the secondary branches grew more or less vertical but 

 irregularly in all directions. Whether this vertical growth 

 of the secondary branches in the dark is due to negative 

 geotropism, I am not able as yet to State with certainty 

 Some cultures which were grown in the dark in an inverted 

 Position showed that the protonema branches grew downward 

 away from the culture medium. These experiments would 

 cend to show that the vertical growth was not due to geotropic 

 sensitiveness, but rather perhaps to negative hydrotropism as 

 in the case of fungi. More experiments in this line are however 

 necessary to make these conclusions certain. 



It was thought that by using a culture medium with 

 less peptone, that the protonema might be brought to a more 

 vigorous development. A second series of experiments was 

 curried out, in which the same culture medium as described 

 above was used, except that only traces of peptone were 

 added. Even in this medium the protonema did not grow 



Vorlesungen über Pflanzenphysiologie, p. 640. 1882. 



