Badania nad pyłkiem potomstwa brzozy ojcowskiej Betula oycoviensis [Investigations on the pollen of the progeny of Betula oycoviensis Basser]

Several crossings have been executed, of which it results that the progeny of Betula oycomensis pollinated by Betula oycoviensis segregates into three groups: the type oycoviensis, type verrucosa and type „nova". The two formes occur as trees, the last mentioned is a small shrub. It has been established that the arithmetic means of the pollen diameter of the three types of birches hardly differed among themselves. As regards the degree of development, there were only very slight differences between the particular types within one generation and between generations. On the other hand, there were fairly great individual differences among the particular specimens as regards the size and degree of development of the pollen grains. These values underwent changes from year to year