142 



part floating on the surface. In later experiments cavities were 

 hollowed out in the earth and these were filled with water, 

 while the rest of the earth was left wet, but not flooded. It 

 was found that the spores germinated more promptly in the 

 water than on the wet earth, and this suggested that probably 

 in nature germination occurs where spores fall in slight depres- 

 sions which could be filled with water for a time after heavy 

 rains. The prothallia of Helminthostachys, — to judge from* 

 the locality where they were found in the Barawa Forest, — 

 occurred only where the forest was subject to inundation, and 

 it may be that free water is necessary for the germination of 

 0. moluccanum, or at any rate facilitates germination. However, 

 spores of Helminthostachys which were sown both on water 

 and on earth could not be made to germinate. Spores of 

 0. moluccanum sown later in a flower pot which was kept 

 standing in water, but which was not flooded, did not germi- 

 nate at all, or only showed very few germinating spores. The 

 free prothallia found in Buitenzorg occurred in low ground 

 between the projecting roots of trees where water might very 

 well settle for some days in wet weather. 



The spores of all the forms examined are of the tetrahedral 

 type characteristic of other species of Ophioglossum, and the 

 outer spore membranes are quite colorless, so that the spores 

 appear either white or of a pale yellow tint There was a 

 marked difference in the size of the spores, and there was a 

 difference in the surface sculp turings and the contents. An 

 examination of the plants showed that at least two marked 

 forms — probably distinct species — were present. One, pro- 

 bably the true 0. moluccanum (Fig. 153), is somewhat smaller, 

 with a pointed lanceolate sterile segment and medium-sized 

 coarsely reticulate spores. The spores have dense granular 

 contents with a considerable amount of starch as well as oil 

 and albuminous granules. The other most striking form was 

 usually somewhat larger, with cordate or nearly cordate sterile 

 segment of the leaf, and decidedly larger, flnely reticulate 

 spores, more transparent and having little or no starch. Both 



