TABLE OF CONTENTS 
Experimental investigations on the* = mses 
skya (with nineteen figures) - James R. Weir 
Chemical changes accompanying abscission in Coleus 
Blumei. cc from the Hull Botanical 
Laboratory 240 - - - - -Homer C. Sampson 
ae of the Taxineae (with plates I, IT) Mary C. Bliss — 
Significance of resinous tracheids (with five — Samuel J. Record 
Determination of wilting. Contributions from t 
Hull Botanical Laboratory 241 (with five fag Arthur L. Bakke 
Notes on American willows. I. The species related 
to Salix arctica Pall. - - - - Camillo Schneider 
Fecundation and formation of the primary endospe 
nucleus in certain Liliaceae (with plates III-V) Mildred N. othnagel 
Factors determining character and distribution of 
food reserve in woody plants (with two figures)Edmund W. Sinnott 
Suspensor and early embryo of Pinus. Contributions 
from the Hull Botanical ssecenpsaee See 242 fri 
plates VI-X and three figures) - John T. Buchholz 
Notes on North American trees. II. Carya - - C. S. Sargent 
Fertilization in Lilium. Contributions from the 
Hull Botanical ny 243 es a 
MI-XTM) = -  - - Wanda Weniger 
Abnormal —— in preenre ve three ; 
fi 
gures J. G. Brown 
A contribution to the life iy of I sesaibens Sultani : 
(with plates XIV, XV) - - - - - - Alice M. Ottley 
Notes on American willows. II. The species related 
to Salix glauca L.- - - = - = = = Camillo Schneider 
The sporangia of Thismia americana (with plate XVI) Norma E. Pfeiffer 
Root variations induced by carbon dioxide 0s addi- 
_ tions to soil (with nine figures) -  H.A. Noyes, J. F. 
Trost, and L. Yoder 
