CONTRIBUTIONS FROM THE DEPARTMENT OF ; 



BOTANY OF COLUMBIA UNIVERSITY.— No. ii^. \ 



Chromatin-reduction and Tetrad-formation 



in Pteridophytes. 



(Plates 295, 296.) 



BY GARY N. CALKINS 



[Reprinted from The Bulletin of the Torrey Botanical Club, Vol. 24, No. 3, March, 1897.] 



