8 THE OPHIOGLOSSALES 



and apparently the prothallium of O. pendulum is strictly saprophytic throughout 

 its existence. 



The extremely favorable conditions for plant growth at Buitenzorg made this 

 an unusually promising place for studying germination, and very soon after my 

 arrival there a quantity of plants of Ophioglossum moluccanum, or what was sup- 

 posed to be this species, was secured, and the spores were sown. Subsequent study 

 showed that at least three species grew together at Buitenzorg, so that it is not at 

 all certain that all of the germinating spores and the prothallia which were col- 

 lected later really belonged to O. moluccanum. 



Since in all previous experiments with the Ophioglossaceae germination had 

 been very slow, it was with much surprise that the first lot of spores that were sown, 

 when examined a week later, were found to be germinating very freely and had 

 evidently been growing for some days. New sowings were made, and in some cases 

 the first germination stages were evident within three days from the time the spores 

 were sown. Inasmuch as the spores contain no chlorophyll, this rapid germina- 

 tion is really remarkable. In the most favorable instances the greater part of the 

 spores germinated and many thousand germinating spores were studied. 



The first sowings were made upon earth taken from where the plants were 

 growing; the earth was placed in small glass dishes and flooded with water; the 

 spores were then scattered over the surface of the water, some sinking, but the 

 greater 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 under natural 

 conditions germination occurs where the spores fall in slight depressions which are 

 filled with water for a time after heavy rains. The prothallia of Helmtnthostachys, 

 to judge from the locality where they were found in the Barrawa Forest, occurred 

 only where the forest was subject to inundation, and It may be that immersion in 

 water is necessary for the germination of Ophioglossum moluccanum, or at any rate 

 facilitates germination. The older prothallia of this species which were found in 

 Buitenzorg were growing in low ground between the projecting roots of trees, where 

 water might very well stand for some days in wet weather. 



The first sign of germination consists in the enlargement of the spore contents, 

 which soon burst the rigid outer membrane along the three lines upon its ventral 

 face, and through the cleft thus formed the spore contents, surrounded by the col- 

 orless inner membrane ("endospore" or "intine") protrude as a blunt papilla 

 (plate I, fig. 2). The first division wall is transverse and is soon followed by a 

 second wall in the upper cell (i. e., the one turned away from the opening). The 

 second wall is at right angles to the first, and the young prothallium now consists of 

 three cells, the basal one, which is partly exposed through the cleft at the upper side 

 of the spore, and the two upper cells, which have more dense contents than the 

 basal one. The basal cell in position corresponds to the first rhizoid in the germi- 

 nating spore of the typical ferns, but it was never found to become extended into a 

 true rhizoid, and no rhizoids were seen in any of the very young prothallia. 



While Ophioglossum moluccanum and O. pendulum agree very closely in the 

 early stages of germination, in the latter species no trace of chlorophyll can be 

 detected at any time, but in 0. moluccanum it is not uncommon to find from one to 

 three chloroplasts present. These chloroplasts are very pale in color, but it is 

 certain that a small amount of chlorophyll is present in some cases. 



While most of the young prothallia of Ophioglossum moluccanum do not advance 

 beyond a three-celled stage, a few were found in which there were four cells, but all 



