a at a a a i ea 
VOLUME X\XIII NUMBER 3 
DOPANICAL. CAgET EE 
MARCH 1897 
CONTRIBUTION TO THE LIFE HISTORY OF SALIX? 
CHARLES J. CHAMBERLAIN. 
(WITH PLATES XII-XVIII) 
Many considerations combine to make the embryology of 
Salix an inviting subject. Taxonomists at present place it so 
near the most primitive dicotyls that it becomes interesting from 
a phylogenetic standpoint. Treub’s researches upon Casuarina 
(22) have yielded some remarkable results. He finds that it 
has a great number of macrospores, but no synergids and no 
antipodals; that there i is no primary endosperm nucleus formed 
_by the fusion of polar nuclei, but an endosperm formed before 
fertilization ; that cell walls are formed about the oosphere and 
its accompanying cells before fertilization; and finally that the 
_ pollen tube enters by way of the chalaza instead of the micro- 
_ Pyle. Treub considered these results so significant that he pro-_ 
, Posed: a primary division of angiosperms into chalazogams and 
‘ms, Casuarina its the sole ge of - —— 
