PREFACE. 
The text which forms this volume consists of reprints of the several papers 
contributed by me to the ‘ Annals of Natural History,’ wherein they ap- 
peared at intervals extending over a period between September 1860 and 
May 1869 ; these are now here collected, revised, and accompanied by the 
plates intended to illustrate the subjects referred to. Among them will 
be found a monograph of the Calyceracea, with analyses of the peculiar 
structure of that family ; also observations on the carpical structure, orga- 
nization, and affinities of the Bignoniacecs and Crescentiacea, followed by 
descriptions of the genera Adenocalgmna and Tanaecium, and of some of 
then’ species. At the time these were made, I had carefully examined and 
defined the limits of most of the genera of that family, intending to continue 
their publication thus commenced ; but I suddenly desisted, out of respect 
to Dr. Seemann, who I learned was then engaged in a similar task. In 
1863, however, I furnished an outline of some of my proposed genera and 
species, in the ‘ Proceedings of the Royal Horticultural Society ’ for that 
year, on the occasion of determining the Bignoniaceous plants collected in 
Brazil by Mr. Weir for that Society. Finally I thought it woidd best serve' 
the interests of science to hand over all my notes, drawings, analyses, and 
specimens to M. Bureau, who has been for some time engaged in pre- 
paring an elaborate monograph of the BignoniacecB for the great work, 
the ‘ Flora Brasiliensis.’ In the meanwhile my memoir on Crescentia has 
appeared in the ‘ Linnean Transactions.’ 
As there was much uncertainty about the plants actually employed in 
