RATTLESNAKE FERN AND ADDER'S-TONGUE. 47 



* 



primitive way of bearing spores than is found in 

 most ferns and is considered an indication that the 

 Ophioglossums are very ancient forms. 



The rootstock is short and produces many short fleshy 

 roots. Here and there adventitious buds may be formed 

 upon them and new plants result. In some species in 

 this genus, this is said to be the chief method of propa- 

 gation. The prothallia are apparently seldom developed, 

 perhaps because this way of getting new plants is so 

 much surer. The curious manner in which the adder's- 

 tongue appears and disappears in the same spot in differ- 

 ent years has given ground for the belief that the plants 

 occasionally rest for a season. It is also conjectured that 

 the prothallia may form resting bodies as the prothallia 

 of certain other species of ferns are known to do. 



In 1897 a party of botanists found a colony of small 

 Ophioglossums in southern New Jersey, specimens of 

 which were subsequently described as O. arenarium. 

 This is apparently only a depauperate form of the com- 

 mon species due to the sterile soil in which it grows. It is 

 described as about half the size of vulgatum with a rather 

 lanceolate sterile portion in which there are from five to 

 seven basal veins. The describer writes of it " It seems 

 a little difHcult to tell some of the young fronds of 

 O. vulgatum from the mature ones of O. arenarium, and 

 yet the extremes are so different and the habit and 

 habitat so distinct that I have concluded to retain them 

 as separate species. That O. arenarium has originated 

 from O. vulgatum and that intermediate forms may be 

 found in young or poorly developed specimens, does not 

 alter the view from the modern standpoint of evolution." 

 It is probable that the majority of botanists would con- 

 sider this more properly placed as O. vulgatum arenarium 

 and not as a separate species. 



