▁of ▁related ▁hy br ids . ▁The ▁ster ile ▁off spring ▁of ▁the ▁walking ▁f ern ▁( A .   rh iz oph yll um ) ▁and ▁the ▁eb ony ▁s ple en wort ▁( A .   pl aty neur on ), ▁A .   ×   eben o ides ▁is ▁intermediate ▁in ▁morph ology ▁between ▁its ▁two ▁parents , ▁combining ▁the ▁long , ▁narrow ▁bla de ▁of ▁A .   rh iz oph yll um ▁with ▁a ▁dark ▁stem ▁and ▁lo bes ▁or ▁pin na e ▁similar ▁to ▁those ▁of ▁A .   pl aty neur on . ▁While ▁A .   ×   eben o ides ▁is ▁generally ▁ster ile , ▁fert ile ▁spec im ens ▁with ▁double ▁the ▁number ▁of ▁chrom os om es ▁are ▁known ▁from ▁Hav ana ▁Glen , ▁Alabama . ▁These ▁fert ile ▁all ot et rap lo ids ▁were ▁rec lass ified ▁as ▁a ▁separate ▁species ▁named ▁A .   t ut w il era e ▁in ▁ 2 0 0 7 , ▁retain ing ▁the ▁name ▁A .   ×   eben o ides ▁for ▁the ▁ster ile ▁dip lo ids ▁only . ▁ ▁The ▁hy brid ▁nature ▁of ▁A .   ×   eben o ides ▁was ▁sus pected ▁at ▁the ▁time ▁of ▁its ▁discovery ▁in ▁ 1 8 6 2 , ▁but ▁the ▁existence ▁of ▁f ern ▁hy br ids ▁was ▁scientific ally ▁controvers ial ▁at ▁the ▁time . ▁( The ▁existence ▁of ▁the ▁fert ile ▁individuals ▁in ▁Hav ana ▁Glen ,