TABLE OF CONTENTS 



tAGE 



Hybndization and germ cells in Oenothera mutants. 

 Contributions from the Hull Botanical Labora- 

 tory. XCIII - - - - - - Reginald Ruggles Gates i 



Morphological and anatomical studies of the vegeta- 

 tive organs of Rhexia (with plates I and II) - Theo. Holm 22 



The sporangium of the Ophioglossales. Contribu- 

 tions from the Hull Botanical Laboratory. XCIV 

 (with plates III and IV) - - - - - L. L. Burlingame 34 



The roots of Lycopoditim pithyoides. Contributions 

 from the Hull Botanical Laborator)\ XCV (with 

 plates V and VI and one figure) - - - Alma G, Slokey 57 



rphology 



spore forms in rusts 



H. Christman 81 



Development of the walls in the proembryo of Pinus 

 Laricio. Contributions from the Hull Botanical 

 Laboratory. XCVI (with plates VIII and IX) - N. Johanna Kildahl 102 



Undescribed plants from Guatemala and other Cen- 

 tral American republics. XIX - - - - John Donnell Smith 108 



Microcycas calocoma. Contributions from the Hull 



Botanical Laboratory. XCVII (with plates X- 



XIII and fourteen figures) - - . - Otis W . Caldwell 118 



Apogamy in Nephrodium. Contributions from the 



Hull Botanical Laboratory. XCVIII - - Shigio Yamanouchi 142 . 



The structure and relationship of the Potamogeton- 



aceae and allied families (with plates XIV-XVIII 



and three figures) Mintin Asbury Chrysler 161 



The male gametophyte of Dacrydium. Contributions 



from the Hull Botanical Laboratory. XCIX 



(with plate XIX) 



Mary 5. Young 189 



Biyological papers. I. The origin of air chambers. 

 Contributions from the Hull Botanical Labora- 

 toiy. C (with twenty-two figures) 



Charles R, Barnes and W, /, G. Land 197 



The development of the sporangium of Lygodium, 

 Contributions from the Hull Botanical Labora- 



figures 



Bin ford 214 



figures) F. L, Stevens 241 



importance 



tions for plants. IL Fresh-water and terrestrial 



plants (with seven figures) - - - - W. J. V, Osterhout 259 



t 



