64 



opposed conditions as an adaptation to the changes obtaining in 

 the swamp habitat. In the early spring and summer moist, con- 

 ditions prevail. In the late summer and fall, the swamps pre- 

 sent conditions conducive to transpiration and thus the xero- 

 phytic features of the plant come into play. 



Plants from Georgia in the herbarium of the New York Bo- 

 tanical Garden were found to possess in all cases minute depres- 

 sions or pits along the phyllode. Beneath the floor of the pit is 

 a smaller-celled compact secretory tissue containing resin and 

 serving as a resin gland. 



By submerging some plants and growing others in a saturated 

 atmosphere, a marked change in the phyllodes produced after 

 the change in the conditions was inaugurated became evident. 

 The phyllodes were hollow, absolutely terete, and exhibited 

 no trace of resin glands. Microscopic examination revealed an 

 entire absence of cuticle, hypoderm, secretory tissue and central 

 stellate tissue, a reduction of the number of stomata, of the 

 xylem in the bundles, of the chlorenchyma, and of the endoderm. 

 These changes are such as tend toward a suppression of xero- 

 phytic features or serve as means of adaptation to moist conditions 

 and therefore hydrophytic in their nature. The xerophytic 

 nature of the normal form is so plainly indicated by the thick 

 cuticle, the hypoderm and the possession of resin glands, that it 

 seems reasonable to supersede Briquet's explanation of the struc- 

 ture of the plant by one less cumbersome. This is, that in the 

 modified plant we see the hydrophytic form but that normally 

 Oxy polls filiformls is never a hydrophyte but rather a swamp 

 xerophyte. 



The paper was discussed by Dr. MacDougal, Dr. Barnhart 

 and Professor Lloyd, Dr. MacDougal remarking upon Oxypolls 

 filiformls as a fine example of plasticity in plants. 



The second paper was by Mr. Edward W. Berry and was en- 

 titled, " Notes on the Matawan Formation and its Flora." 



The Matawan formation was briefly characterized and its areal 

 and vertical range discussed. It consists of clays and sands 

 closely related to those of the Raritan formation, and extends 

 from Raritan Bay in Monmouth County, New Jersey, southwest- 



