14 



THE OPHIOGLOSSALES 



These break off at the least touch, and no doubt serve to propagate the gainetophyte, 

 which is apparently capable of unlimited growth in this way. It is often impossible 

 to say whether the smaller gametophytes that are found loose in the humus are 

 anything more than branches which have become spontaneously separated from 

 the larger prothallia. 



The older parts of the gametophyte are dark brown in color, but the tips of the 

 branches are white, as, in the other species. The branching, as we have seen, may 

 be very irregular, and old fragments kept moist often send out great numbers of 

 adventitious buds (plate i, fig. ii) which apparently in time develop into normal 

 prothallia. A number of the ^commoner forms are shown in the figures. Plate i, 

 fig. 14, represents the largest one met with. This is by no means complete, as a 



Fig. 4. 



A. Longitudinal section of apex of gametophyte of Ophioglossum moluccanum. © antheridia; ? archegonia; 



«m, two-celled embryo. 



B. Apex more highly magnified, showing apical cell, x. 



C. Transverse section of a branch of the gametophyte of Ophioglossum pendulum. 



D. Apical cell of same. 



E. F. Short hairs from gametophyte of 0. pendulum; in E may be seen the endophytic fungus filaments. 



number of branches were unavoidably broken off in removing it from among the 

 tangle of roots in which it was embedded. This specimen measured about 15 

 millimeters in diameter — more than twice the size of the largest specimen secured by 

 Lang. The surface of the older parts of the prothallium shows a slightly roughened 

 appearance due to the numerous very short papillate hairs which occur upon 

 it. These are never of the slender form found in 0. moluccanum and perhaps 

 are not properly to be considered as rhizoids. Dotted over the surface are pale 

 brown spots, easily seen with the naked eye, and these on examination are found to 

 be the large, empty antheridia. The branching is sometimes dichotomous, but 

 lateral branches may arise at almost any point, and old fragments of the prothallia, 

 as already indicated, often develop many adventitious buds, a condition of things 

 which apparently obtains also in the long-lived prothallia of 0. vulgaUim. The 

 rate of growth of prothallia kept by the writer for more than a year, as well as their 



