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not triangular. Some fertile pollengrains of a normal size contain 
starchgrains. I find some large globe-shaped pollengrains, full of 
starchgrains; 29°/, are sterile. | perform many more enumerations 
in pollen of flowers from other racemes, out of this same lot. I 
always find the same phenomenon and a sterility, from 29 to 30°/,. 
Fics. im, 6: 
8. The pollen is not sticky. The nuclei are clearly visible. The 
sterile pollengrains are all ellipsoidical. In the preparations float 
some starchgrains, 66°/, are sterile. 
City of Haarlem, single-flowered yellow, 23 chromosomes. 
1. The pollen is not sticky. The anthers are large and normally 
developed, but they contain hardly any pollengrains. The few there 
are, nearly all have abnormal pollen-tubes with several nuclei or 
they are large, globe-shaped and filled with starchgrains. | examine 
several racemes. Always the phenomenon is the same. 
King of the Yellows, single-flowered yellow. 
1. I examine the pollen in the anthers of green buds. Every- 
where the pollen shows NEMmuc's phenomenon. 
2. All pollengrains are normally formed. Only 2 °/, are sterile. 
Yellow Hammer, single-flowered yellow, 16 chromosomes. 
1. The pollengrains are all normal; 17'/,°/, are sterile. 
2. Id. 14°/, are sterile. 
3. The pollen is sticky; some pollengrains have a wide, abnormal 
pollen-tube; 87 °/, are sterile. 
4. The pollen is not sticky. The various preparations never show 
a normal fertile pollengrain. The pollen shows perfectly Nemsc’s 
phenomenon. 
5. I examine the pollen in all flowers of one raceme. 
Undermost flower: the anthers contain only few pollengrains, 
which are all sterile. 
Next flower: there are sterile pollengrains, others with abnormal 
pollen tubes and others again that are large and globe-shaped, full 
of starchgrains. 
Next flower: pollen as in the preceding flower; besides there are 
triangular, sterile pollengrains, while the 2 former flowers had only 
ellipsoidical sterile ones. 
Next flower: pollen as in the former, but besides some fertile 
pollengrains present. 
Next flower: as in the former, but more fertile pollengrains pre- 
senteren 273/,°/,- 
Next flower: as in the former, but the fertility is 35'/, °/,. 
So if we compare the pollen of the various flowers, going from 
