VOLUME XXXIV 



NUMBER 5 



Botanical Gazette 



NOVEMBER, 1902 



ON THE DEVELOPMENT OF CERTAIN PIPERACEAE. 



Duncan S. Johnson. 



(with plates IX- 



In an 



(J 



F 



p. 9) that Piper and Heckeria have ''essentially typical Angio- 

 sperm embryo-sacs." This statement was based on observations 

 covering the critical stages in the development of this structure. 

 Since then I have studied the embryo-sac in these genera in 

 detail, for the purpose of discovering any possible clue to the 

 derivation of the peculiar type of embryo-sac found in the 

 related genus Peperomia. The more important results of a study 

 of these forms are given here, together with an account of the 

 fate during germination of the various structures found in the 

 fruit of Peperomia. 



I. THE OVULE, SEED, AND FRUIT OF PIPER. 



The two species of Piper studied were Piper adwica L. and a 

 species determined as PipermediMm ]2lC(\, The development of 

 the former, as far as followed, agreed closely with that of Piper 

 medium; it will therefore suffice to describe and figure the latter 

 in detail. 



The flowers of Pipermediiim occur rather loosely scattered on 

 a spike 4 to 8"=^ in length. In the development of the flower 

 the three outer stamens appear first, then the three inner ones. 

 Each stamen has four pollen-sacs {Jig. i,ps), and the whole 

 development of the stamens shows no noteworthy peculiarities. 

 Soon after the stamens are formed the wall of the ovary appears 



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