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fertile ones I observe some that are filled with starchgrains. There 
also occur pollengrains with abnormal pollentubes. Not in all anthers 
I find germinated pollengrains. The sterility amounts to at least 50 °/,. 
Bloksberg, double-flowered blue. 
1. I examine the anthers out of a green bud. The pollen is not 
sticky and clearly shows Némsc’s phenomenon. Van Speijk, double- 
flowered blue, 21 chromosomes. 
1. The anthers of a green bud are examined. The preparations are 
entirely in accordance with the drawings Nemec has made of the 
abnormal pollen-tubes with many nuclei, of the large globe-shaped 
pollengrains full of starch and of the sterile pollengrains. 
2. The petaloid anthers contain little pollen. but this normal; 25°/, 
is sterile. 
To this I join a table, which renders, in a surveyable form, the 
content af the descriptions. Under the figures 1° — 10° the result of 
the numeration is indicated for every variety, in accordance with what 
stood behind the same figure in the descriptions. These figures indicate 
the percentages of sterility; by the letter 2 Nemxc’s phenomenon is 
indicated. The capital letter in parenthesis shows the origin of the 
raceme from which the pollen was taken. 
Further I put the number of chromosomen occuring in the somatic 
cells, behind the varieties of which I know this number. 
The principal conclusions down from the preceding examinations, 
with a view to the purpose of this publication, are the following: 
1°. The pollengrains in normally formed anthers, as well as those 
in petaloid anthers, may germinate with abnormal pollentubes with 
several nuclei. So Némsc’s opinion that this phenomenon should only 
occur in double flowers, is inaccurate. 
2°. The phenomenon has nothing to do either with the quaestion 
of the hyacinth-varieties being heteroploid or not. It may be observed 
in diploids as well as in heteroploids. 
3. From the fact that in one and the same raceme or in different 
racemes of the same variety we now find quite normal pollengrains, 
now pollen showing Nemec’s phenomenon, we may infer that the 
abnormally germinated pollengrains with several nuclei are caused 
by eaternal and not by internal influences. 
After a more superficial examination one would possibly be inclined 
to ascribe this kind of deviations simply to wnder- or overfeeding, 
causes that are also so often named to explain the abnormal increase 
of the number of chromosomes. NEmrc thought that as the cause of 
the existence of the abnormal pollentubes with several nuclei was 
to be considered the overfeeding of the petaloid anthers. The finding 
