THE FERN BULLETIN 



35 



would seem to place it in a habitat similar to that pre- 

 ferred by Asplenium pinnatifidum Mett. or Asplenium 

 Bradlcyi Eaton which, while not averse to some 

 moisture and shade, can get along somewhat exposed. 

 From the original description of A. Ferrissi I would 

 consider that it grew under similar conditions in about 

 31° 35 J North latitude at an elevation of 7,000 feet, 

 though surrounded by a country more arid than the 

 Himalayan region. It will be noted that it occurs sev- 

 eral degrees farther south in Arizona than in India. 



It is difficult to theorize on such an anomalous dis- 

 tribution. The occurrence of A. alternans in Abys- 

 sinia might be considered as evidence of a once more 

 general distribution ; in Arizona it may seem to be 

 evidence that under similar conditions similar species 

 may in the course of time be evolved in widely separ- 

 ated localities. Or, we may consider other agents of 

 plant distribution. Since the appearance of plant life 

 upon the earth, the meteorological factors, wind, 

 moisture, 'heat and light have been at work. At var- 

 ious times and in many parts of the earth their work 

 has been assisted, interrupted or rendered nugatory 

 by geological agents. Seismic upheavals have im- 

 posed tall mountain ranges; sinkings have caused 

 deep wide oceans beyond which species could not mi- 

 grate and which to some degree isolated species, some- 

 times genera, families or even tribes. A gigantic up- 

 heaval may account for the presence of a number of 

 common American ferns in Japan such as Adiatum 

 pedatum, Onoclea sensibitis, Botrychium ternatum 

 and others. May not the Japanese Camptosorus 

 Sibericus and our Camptosorus rhisophyllus have had 

 a common ancestor? Vicarious endemism? The 

 evident affiliation of North America and Asia is fur- 

 ther upheld by the remarkable pairing of western 



