THE GAMETOPHYTE 11 



myself, and also like the locality where most of my specimens of 0. moluccanum 

 were found in Java. This, in connection with my experiments in germinating the 

 spores of O. moluccanum, makes it not unlikely that actual submersion is a necessary 

 condition for the germination in the terrestrial species of Ophioglossum. 



In April 1906, about fifty prothallia of 0. moluccanum were collected by me 

 at Buitenzorg, where, as we have seen, this species is extremely abundant. Only a 

 small number of these were young enough to show the young reproductive organs, 

 and most of them had already developed the young sporophyte. The greater part 

 of these prothallia were found growing together in a slight depression between the 

 projecting roots of a tree. 



These prothallia were slender bodies, from 5 to 10 millimeters in length, and none 

 of them branched. They showed a more or less conspicuous basal tuber, like that 

 described by Mettenius for 0. pedunculosum, and indeed they very closely resembled 

 his figures of the simpler forms of that species, but are very much smaller. The 

 youngest specimen found (plate i, fig. 10) consisted of a small, irregular tuberous 

 body of a brownish color, from which grew a short appendage or branch, the tip of 

 which was white. The older ones also showed this basal tuber, but the cylindrical 

 branch was much longer. Owing to their slender form, the prothallia are not always 

 easily distinguishable from roots, and in some cases a microscopic examination is 

 necessary before one can be sure of their real nature. Growing from the surface are 

 scattered short brown hairs like those described by Mettenius for O. pedunculosum. 

 Archegonia and antheridia are formed at an early period, and can be traced to the 

 base of the fertile branch, or in some cases may be found even upon the tuber. In 

 these specimens the reproductive organs seemed to be formed in rather smaller 

 numbers than is the case either in O. pedunculosum or O. vulgatum. Among the 

 prothallia was one very much larger than the others which had very large numbers 

 of old archegonia. It is highly probable that this represents a second species, but 

 unfortunately there was no means of determining to which of the two or three 

 forms associated under the name O. moluccanum it belonged. 



The cells of the tuber and the lower part of the branch contain the character- 

 istic endophytic fungus, but the greater part of the fertile branch is quite free from 

 this, and the cells appear almost transparent, but they contain numerous small starch 

 granules. The endophyte is much more abundant in the cells of the tuber. The 

 hyphae, which stain readily with gentian violet, are irregular in outline and branch 

 freely. Very often branches can be seen piercing the walls of adjacent cells. 



In the living condition the pointed apex of the prothallium is pure white, and 

 even with a hand lens the projection of the antheridia is clearly evident. Mettenius 

 noticed this "varicose"' appearance of the smaller prothallia in 0. pedunculosum. 

 A median section of the branch shows that the end is decidedly pointed and has a 

 clearly defined apical cell. Owing to the very small amount of material available, 

 no satisfactory transverse section of the apex could be made, and it can not be told 

 whether the apical cell in transverse section is three-sided, as described by Bruch- 

 mann for O. vulgatum, or is four-sided, as it is in 0. pendulum. In the smaller speci- 

 mens antheridia were more numerous than archegonia, although several of the latter 

 were present. The antheridia arise, in general, in acropetal succession, but it is 

 not unlikely that secondary ones may be formed also. The archegonia are scattered 

 among the antheridia apparently without any definite order. In some specimens, 

 especially in the larger ones, the old archegonia were found in great numbers, many 

 more than the antheridia. In other specimens a considerable part of the prothallium 

 was quite destitute of either archegonia or antheridia, and in this respect the pro- 

 thallium of 0. moluccanum differs from that of 0. pedunculosum or 0. vulgatum. 



