Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 90. (Budapest 1998)

Medzihradszky, Zs. ; Bajzáth, J.: The occurrence of arctic-alpine Betula species in the Hungarian Pleistocene

the lowest latitude (in bogs of the alpine-subalpine zone) Betula nana is an acidofrequens ecotype of the species. Betula humilis SCHRANK, 1789 (Figs 5-7) Description, Fruit scales (Fig. 7). The fruit scales are deeply lobed, small, but a little larger than those of Betula nana. They are 2.7-2.75 mm 1.6-1.8 mm in size. The angles between the three lobes are V-shaped. The middle narrow lobe is almost twice as long as the two others. The fruit scale resemble of birdfoot. The width of the lobes is nearly the same. Figs 1-9. Remains of Betula species: 1 = leaf of Betula nana, 2 - pollen grain of Betula nana. 3 = fruit scale of Betula nana, 4 = seed of Betula nana, 5-6 = seeds of Betula humilis. 7 = fruit scale of Betula humilis, 8-9 = seeds of Betula pubescens ssp. tortuosa