tele) BOTANICAL GAZETTE 
prevent pollination. This last precaution was taken because the 
large amount of fruit produced in previous seasons on pistillate 
plants remote from staminate plants made the occurrence of par- 
thenogenesis seem possible. The twigs bearing the catkins polli- 
nated were carefully labeled, both as to the location in which they 
grew and the time of pollination. Again frequent collections (two 
every day) were made for about five days after pollination. 
The first catkin collected had sections cut off each side to allow 
the more easy penetration of the killing fluid, and were then killed 
in toto. Owing to the difficulty in orienting the material, and to 
the fact that the hairs on the bracts made the cutting of smooth 
sections practically impossible, in all the later material the pistils 
and the stamens were picked out of the catkins before killing. 
The young ovaries were killed in Flemming’s weaker solution, 
while some of the later stages in the development of the ovule and 
of the seed were killed in 1 per cent chromo-acetic acid. The 
material was imbedded in paraffin and sections cut from 2-10 # 
in thickness. The stains used were the combination of safranin 
and gentian violet, with the addition of gold orange in some cases. 
The solution of gold orange in clove oil to be used after clearing in 
clove oil was found to be more satisfactory than the alcoholic 
solution. 
Historical 
The work done on Leitneria previous to 1894 was largely taxo- 
nomic, and has been cited by TRELEASE (1) in a paper of that 
year describing the plants of Lettneria found growing in the low- 
lands of southeastern Missouri. He considered the habit and 
distribution of the plant and its various taxonomic features, and 
besides this the structure of the wood, calling attention to its 
extremely low specific gravity, and concluding with a discussion 
of the position Leitneria had held in various schemes of classifi- 
cation. The portion of the paper with which we are most con- 
cerned has to do with the catkins. Of these it is said: 
On mature plants the upper axillary buds are generally flower buds, and 
develop in the autumn into oblong, erect, subsessile, hairy catkins, about half 
an inch long, surrounded at base by bud scales, which pass into the very acute 
scales of the inflorescence. The trees are dioecious. . ... The flowers expand 
