PREFACE, 
In the present paper, the fifth of the series, Mr. Henry Pittier, of 
the Bureau of Plant Industry, United States Department of Agri- 
culture, discusses and describes trees and shrubs of Central America 
and the northern part of South America, hitherto imperfectly or 
not at all known. Most of them are components of the wonder- 
fully rich native Isthmian silva and several are of importance as 
timber trees. A large part of the paper is devoted to a revision of 
the genera Brownea and Browneopsis founded on the extensive ma- 
terial collected by the author in Darien and Venezuela. Mr. Pit- 
tier’s recent observations and collections in Panama permit a better 
understanding of the genera Bombax and Pachira, which has led 
him to segregate two species from Pachira to form the new genus 
Bombacopsis. 
FREDERICK V. COVILLE, 
Curator of the United States National Herbarium. 
Tit 
