15 
CONFERENCE NOTES FOR DECEMBER 
A conference of the Scientific Staff and Registered Students 
of the Garden was held on the afternoon of December 4. 
Mr. Edgar Nelson spoke briefly of his scientific work since he 
was a student at the Garden in 1913-14, reporting especially on 
inspection and control of the citrus canker in Florida and on 
measures employed in Texas for the eradication of the Argentine 
ant which has recently been introduced. 
Dr. H. A. Gleason, associate professor of botany at the Uni- 
versity of Michigan and a former student of the Garden, was 
present and reported on his studies of the genus Vernonia. The 
following i is an abstract of his discussion. 
“Among the sixty or more species of Vernonia in the West 
Indies, there are two introduced species, each representing a dis- 
tinct section of the genus and two species without any close re- 
lationships. There are two or three groups of species without 
relatives in the West Indies. One group of four Cuban species 
finds its nearest relatives in Mexico and Central America. 
Among the other West Indian species which are of South Ametri- 
can derivation, the simplest type of inflorescence, a bracted 
scorpioid spike, occurs in several species distributed as far west 
as Jamaica. From this simple type, other types of inflorescence 
have been developed, characterized by shorter and more leafy 
spikes and by differences in the position of the next vegetative 
branches. Each stage in the development of the inflorescence 
ix associated with a more w esterly distribution, culminating in 
the species of the Bahamas and Cuba. 
“Forms of Vernonia which are apparently hybrids occur 
commonly in the United States. They are found only in the 
overlapping ranges of each of the supposed parents, whose 
morphological characters they combine. In many specimens, 
the achenes are shriveled below and plump only near the apex, 
indicating their probable sterility.” 
A. B. Strout, 
Secretary of the Conference. 
