103 



" Our last field work was done on the .Vaccas Keys, Crawl 

 Keys, and Grassy Key. We secured a good collection of the 

 plants inhabiting these islands, including some additions to our 

 flora, and a view of the remarkably dense growth of the palm, 

 Ihrinax floridana, which is well worth a trip there to see." 

 " Notes on North American Pondweeds ", by Mr. Norman Taylor. 



" A short historical review of previous treatments of the genus 

 Potamogeton shows that Morong (1893) credited 37 species to 

 North America, while Pflanzenreich (1907) lists 42 species and 

 scores of varieties. The forthcoming part of the North Ameri- 

 can Flora will contain descriptions of only 36 species. A 

 decidedly conservative tendency in the conception of specific 

 limitations accounts for the difference in the number of species, 

 and this is based on a more or less fixed adherence to the prin- 

 ciple that in Potamogeton fruit characters are the only ones of any 

 real stability. 



" The usual characters that have been used by monographers 

 and their relative value for taxonomic purposes, was discussed. 

 As an example of the variability of the group, a series of speci- 

 mens showing every gradation between the lanceolate leaves of 

 P. Richardsonii and the orbicular ones of P. biipleiiroides was 

 shown, and the contention was advanced that in all probability the 

 three species P. Richardsonii, P. perfoliati/s, and P. bupleuroides 

 were in reality one aggregate species with trifling differences." 



Discussion followed by Dr. Barnhart, Dr. Rydberg, and the 

 speaker. 



The meeting adjou ed at 4:30 p. m. 



Percy Wilson, 



Secr'etary 

 REVIEWS 



Ward's Trees* 



The little book, which follows the three volumes on Buds and 

 Twigs, Leaves, and Inflorescences and Flowers, is of course de- 

 signed primarily for use in England ; yet, it will prove helpful in 



* Ward, H. Marshall. Trees : A Handbook of Forest Botany for the Woodlands 

 and the Laboratory. Vol. IV. Fruits. Pp. 154. /. 147. 1908. Cambridge, 

 University Press (Putnam's, New York). 



