1918] BUCHHOLZ—PINUS 199 
in fig. 46 or soon after, and the cells of the older portion of the 
secondary suspensor also collapse in turn, so that in an older embryo, 
like that of fig. 51, the upper part of the suspensor cannot be 
studied. 
In order to determine the amount of variation in the early 
suspensor divisions, several hundred preparations of P. Banksiana 
were examined and the types of suspensor development noted. 
af 
5 
AY 
-—_- 
34 112 9 300 
016 
047 953: 
Fic. 2.—Graphic statistical summary of variations in early suspensor divisions of 
Pinus Biakilona: the figures indicate the number of examples of the various types 
of suspensors observed, and their distribution in percentage. 
The results are summarized in the diagrams of text fig. 2. It was 
common in more than four-fifths of the cases examined to find the 
single primary suspensor followed by a r1-celled embryonal tube 
(e:), this followed by 2 or more cells in the next suspensor division, 
after which the tubes interlock and elongate irregularly, as in figs. 
47,49, and 51. Less than one-fifth of the cases were found with the 
Primary suspensor followed by 2 successive single-celled suspen- 
sor divisions and 2 or more tubes in the fourth suspensor division 
€;. Only about 1.6 per cent of the embryos were found to have 
the first embryonal tubes or second suspensor division of 2 cells. 
