Pollination of the eastern dwarf mistletoe

Abstract

Flowering and pollination of Arceuthobiumpusillum Peck growing on Piceamariana (Mill.) B.S.P. were studied in 1978–1980 in Carlton County, MN. Staminate flowers opened in April and abscission was complete by mid-June. The average number of pistillate flowers per aerial shoot ranged from 4.8 to 5.1. From the flowering period to seed dispersal (September of the same year), 36–59% of pistillate aerial shoots were lost. Based on March flower counts, 0.3–2.4 fruits matured per aerial shoot, i.e., 5–35% of pistillate flowers developed into mature fruits. Although insect exclusion studies demonstrated that wind pollination did occur, few grains ofArceuthobium pollen were collected with vaseline slides or a Rotorod sampler. Fifty-nine species of insects trapped on sticky-board traps carried pollen of Arceuthobium. Entomophily is considered the most important pollination mechanism for this dwarf mistletoe.