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below to the top, we observe a gradual transition from pollen which 
is sterile or which shows Némsgc’s phenomenon, to pollen which 
consists of normally formed sterile and fertile pollengrains. 
6. The examination again refers to all flowers of one raceme. 
Undermost tlower: very few normal, fertile pollengrains. For the 
rest: Nemsc’s phenomenon. The anthers are shrivelled and contain 
only little pollen. 
Next flower: like the preceding one; in the abnormal pollen-tubes 
more than 3 nuclei are clearly visible. 
Next 12 flowers: the number of normal fertile pollengrains pre- 
ponderate. 
7. The pollen is not sticky, but it gives a normal impression ; 
36 °/, are sterile. 
8. Besides normally formed fertile and sterile pollengrains there 
occur large, globe-shaped ones and others, of normal size, full of 
starchgrains; 15 °/, are sterile. 
Marchioness of Lorne, single-flowered orange, 16 chromosomes. 
1. In the great number of preparations only sterile pollengrains 
occur and others that have developed abnormal pollen-tubes. 
2. More than 90 °/, of the pollengrains are sterile. 
a: Ad. 
B. Double-flowered varieties. 
La Virginité, double flowered white. 
1. In a drop of water the pollengrains burst very soon. The 
grey colour they show in their protoplasm, has then disappeared 
and the empty, bright yellow coloured exines, on which the wartlike 
protuberances are clearly visible, are left. | make some preparations 
and leave the pollengrains in water for half a minute. If I look at 
them then, it appears that some grains have germinated with an 
abnormal, wide pollen-tube. The protoplasm is now entirely in-the 
pollen-tube and encloses several nuclei. 
Noble par Merite, double-flowered red. 
1. The. flowers are doubled to such an extent that I find only 
few pollengrains. 18 °/, of these are sterile. 
2. The sterility is difficult to make out, because most of the 
pollengrains are in a transition-stage from fertile to sterile. 
3. Most of the pollengrains are sterile. In the fertile ones 2 
nuclei are clearly visible. I observe almost exclusively pollengrains 
that stick together in groups of four. These tetrads consist generally 
of 1 fertile and 3 sterile pollengrains or of 4 sterils ones. The 
sterile ones are fullgrown. Among the sterile as well as among the 
