PREFACE. 



This paper is the second number of the series, by Henry Pittier, 

 entitled New and Noteworthy Plants from Colombia and Central 

 America, the first having been published in Volume 12 of the Con- 

 tributions from the United States National Herbarium, pages 171 to 

 181. It consists chiefly of descriptions of new and little known 

 species of Asclepiadaceae and Cucurbitaceae, keys to the species of 

 several genera, and the characterization of two new genera, Frantzia 

 and Polakowskia, from Costa Rica. 



Frederick V. Coville, 

 Curator of the United States National Herbarium. 



