VI 



CONTENTS 



[volume lviii 



Field notes on the climbing bamboos of Porto Rico 



(with plate XXI) ------ Agnes Chase 



Delayed germination in seed of Alisma Plantago. 

 Contributions from the Hull Botanical Lab- 

 oratory 194 (with eight figures) 



William Crocker and Wiltner E. Davis 



Spore conditions in hybrids and the mutation 

 hypothesis of De Vries (with plates XXII- 



XXV) -- - - - - - - Edward C. Jeffrey 



Reproduction in plants. Contributions from the 



Hull Botanical Laboratory 195 - - - John M. Coulter 



New or peculiar Zygomycetes. 3 : Blakeslea, Dis- 

 sophora, and Haplosporangium, Nova Genera 

 (with plates XXVI-XXIX) - Roland Thaxter 



The forms of antagonism curves as affected by 



concentration (with three figures) - - - ty r . J. V. Osterhout 



Prairie vegetation of a mountain-front area in 



Colorado (with nine figures) - Arthur G. Vestal 



A study of Symphyogyna aspera. Contributions 

 from the Hull Botanical Laboratory 196 (with 

 plates XXX-XXXII) - Florence A. McC or mick 



Spermatogenesis in Marsilia. Contributions from 

 the Hull Botanical Laboratory 197 (with 

 plates XXXIII and XXXIV) - - - Lester W. Sharp 



The plant successions of the Holyoke Range. 

 Contributions from the Hull Botanical Lab- 

 oratory 198 (with map) ----- Edith A. Roberts 



Histology of flax fruit (with four figures) - - Kate B. Winton 



The transpiration of emersed water plants: its 

 measurement and its relationships (with three 

 figures and fourteen charts) - - - - Charles H. Otis 



Contributions to the knowledge of the diaphragms 

 of water plants. I. Scirpits valid us (with 

 sixteen figures) ------ Laetitia M. Snow 



Fasciation (with seven figures) - - - - M . A. Brannon 



Briefer Articles — 



Philippe Edouard Leon van Tieghem (with por- 

 trait) -------- J } m M. Coulter 



Retention of chlorophyll through the paraffin 



process - - - E.G. Anderson 



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