CONTENTS 



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Page 



1. Reports for the Year 1909: 



a. Report of the Officers of the Board 7 



6. Twenty-first Annual Report of the Director 11 



2. Scientific Papers: — 



a. The Algal flora of the Missouri Botanical Garden. — 



By Ada Hayden 25 



6. Periodicity in Spirogyra. — 



By C. H. Danforth 49 



c. The fungous root tubercles of Ceanothus americanus, Elaeag- 



nus argentea, and Myrica cerifera. — 



By E. G. Arzberger 60 



d. Development and nutrition of the embryo, seed and carpel 



in the date, Phoenix dactylifera L. — 



By Francis E. Lloyd 103 



e. Illustrated studies in the genus Opuntia-III. — 



By David Griffiths 165 



/. Abnormalities in Oenothera. — 



By R. R. Gates 175 



g. Botrytis as a Parasite upon Chrysanthemums and Poin- 

 settias. — 



By Pcrley Spaulding 185 



h. Fungi of Clay Mines. — 



By Perley Spaulding , 189 



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