THE ROCK SPLEENWORTS. 171 



species produces young fronds at the apex, but only rarely. 

 In plants that have this tendency to be vivaparous, a sud- 

 den check, as by cold, just as the fronds are fruiting, is 

 said to greatly increase it. In cultivation the produc- 

 tion of young plants in this way is much more common 

 than when they are growing wild. The sori are seldom 

 plentiful and are borne in a double row on each pinnule 

 and open toward the midvein. The spores are frequently, 

 perhaps always, abortive. 



This species has been reported from stations in Ver- 

 mont, Connecticut, New York, New Jersey, Pennsylvania, 

 Virginia, Illinois, Indiana, Kentucky, Missouri and Ala- 

 bama, but the records usually rest upon very few speci- 

 mens, often only one. So far as known, there is only one 

 locality where it is plentiful a deep ravine near Havana, 

 Alabama. 



Prof. Underwood who collected it in this spot writes as 

 follows concerning it. " Its nearest congener is As- 

 plenium pinnatifidum but the frond is much thinner than 

 in that species. In habitat, however, it is very close to 

 that species, growing under overhanging rocks ; in this 

 respect it is .totally unlike both A.ebeneum and Camp- 

 tosorus, its supposed parents. It appears to be multiply- 

 ing, as many young plants were seen in the rock crevices. 

 This myth of hybridity may be put aside, for Asplenium 

 ebenoides is as clearly defined a species as we possess in 

 the genus Asplenium and has no near relatives outside 

 its own genus." The plant figured was collected by 

 Prof. Underwood at the Alabama station. 



There are two other spleenworts for which a place is 

 sometimes claimed among American ferns, though the 

 proof of their occurrence in this country rests upon 



