8 MISSOURI BOTANICAL GARDEN BULLETIN 
Duggar, B. M., and Joanne L. Karrer. ‘‘The Sizes of the 
Infective Particles in the Mosaic Disease of Tobacco.”’ 
Burt, E. A. ‘‘The North American Species of Clavaria, 
with Illustrations of the Type Specimens.”’ 
Pfeiffer, Norma E. ‘‘Monograph of the Isoetaceae.’ 
Payson, E. B. ‘‘A Monographie Study of the Genus Thely- 
podium and Its Immediate Allies.’’ 
Pring, G. H. ‘‘A New Hybrid Nymphaea.”’ 
In addition to the preceding, those listed below, by mem- 
bers of the Garden staff, have appeared in gardencraft and 
other periodicals. Besides these, attention should be drawn 
to many shorter and popular articles in the BULLETIN, and 
more especially to the lists of native and exotic plants suit- 
able for the gardens of Missouri and adjoining states. 
Jensen, L. P. ‘‘A College Course for Nurserymen”’; ‘‘ Old- 
est Living Trees’’; and ‘‘Publications of Interest to Park 
Executives.’’ Parks and Recreation, 1922. 
Pring, G. H. ‘‘Factors to Be Considered in Breeding 
Water-Lilies.’’ Gardeners’ Chronicle of America, 1922. 
Pring, G. H. ‘‘The Orchid Exhibit at the Missouri 
Botanical Garden.’’ Gardeners’ Chronicle of America, 1922. 
Scientific and Popular Lectures—During the year a num- 
her of lectures have been delivered, or papers read, on scien- 
tifie and popular topics by members of the scientific and Gar- 
den staffs to special audiences as follows: 
L. P. Jensen, January 9, before the St. Louis Florists’ Club, 
‘‘Our Vanishing Wild Flowers.”’ 
G. H. Pring, January 13, before the St. Louis Florists’ 
Club, ‘‘A Trip Through the American and African Tropies.”’ 
G. H. Pring, January 31, before the Men’s Club of the 
Church of the Redeemer, ‘‘The Relation Between Insects and 
} lowers.’’ 
B. M. Duggar, February 3, before the biologists of Wash- 
ington University, ‘‘Filterable Diseases of Plants and Some 
Recent Studies on the Mosaic Disease of Tobacco.”’ 
George T. Moore, February 22, a discussion under the aus- 
pices of the St. Louis Natural History Museum Association, 
‘*Co-operation of Civie and Scientifie Institutions in Estab- 
lishing a Natural History Museum in St. Louis.”’ 
George T. Moore, March 1, before the Centenary Methodist 
Church, ‘‘What to See at the Missouri Botanical Garden.”’ 
B. M. Duggar, March 3, before the Webster Groves Nature 
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