It seems incredible to me, as a matter of probabilities, that 

 any plant can be scattered from Vermont and Connecticut to 

 Alabama, and be found only with the x other two species, and 

 so rarely, if it is not a hybrid between them. If it were more 

 abundant it would be easier to look upon it as a distinct species, 

 for similar plant-groups are familiar to every botanist. In 1897, 

 Professor Murrill wrote an account of his discovery of the fern 

 in Virginia. He concludes that it is "a distinct spleenwort." The 

 botanies all state that the veins are free in our species of 

 Asplenium, while the areoles are a prominent feature of the 

 venation of Camptosorus. Professor Murrill says "another in- 

 teresting link connecting it with the walking-leaf is the areolate 

 structure of its veins," although Eaton and others say the veins 

 are all free. Specimens from Virginia and Alabama, and my 

 own from Maryland, show occasional areoles exactly like those 

 of Camptosorus. But this evidence does not convince Professor 

 Murrill as it once did the writer. That particular argument has 

 recently lost much of its force by the recent discovery of numer- 

 ous areoles of exactly the same type in fronds of A. pinnatifidum 

 from Pennsylvania. Thirty-two areoles were counted in seven- 

 teen fronds of all sizes. Several fronds had four or five. 



About the same time that the article written by Professor 

 Murrill was published, Dr. Underwood gave an account of his 

 ■\isit to the Havana locality in the Botanical Gazette (xxn, p. 410, 

 1896). He found the plants in all stages from the youngest up 

 to mature plants, and he concluded that it is not a hybrid but a 

 well defined species, assuming that a hybrid is necessarily sterile. 

 If this assumption be true, further argument is useless, and we 

 can no longer look upon the plant as a hybrid, for it undoubtedly 

 reproduces itself from spores at Havana. It reems to me that this 

 argument is satisfactorily disposed of by Maxon. There is at 

 least one well authenticated instance of fertility in a fern hybrid, 

 namely, in the cross between Polystichum angulare and P. 

 aculeatum. Would it not be possible then for A. ebenoides to 

 be fertile even though other hybrids may have proved to be 

 sterile? A piece of affirmative evidence is of more weight than 

 much negative evidence. Of course the most conclusive evidence 

 would be the actual production of a hybrid. 



One of the peculiarities of hybrids is a decided tendency 

 towards variation of form. This trait is quite marked in 



