The sticky seed of juniper dwarf mistletoe (Arceuthobium oxycedri) from the Crimea

Description:

The sticky seed of juniper dwarf mistletoe (Arceuthobium oxycedri (DC.) M. Bieb) from the Crimean Peninsula ̶ a semi-parasitic species of Holarctic Cupressaceae hosts parasitizing Eastern prickly juniper, Juniperus deltoides R.P. Adams, Greek juniper, J. excelsa M. Bieb. and Oriental thuja, Platycladus orientalis (L.) Franco. Among the unique features of Arceuthobium spp. are ballistic seed dispersal primarily achieved through a hydrostatically controlled explosive discharge mechanism and thermogenesis. Seeds of A. oxycedri are ~0.9−1 mm long and ~0.4−0.5 mm wide, with an elongated pedicel on the proximal (acuminate) apex. A. oxycedri seeds are covered by a sticky viscin (“birds glue”) forming a snow-white cap on the distal (roundish) apex and thin layer on the surface of the seed. After the hydration viscin forms sticky stands required for parasite attachment to the host branch and/or sporadic ornithochory. The picture was taken using stereomicroscope Axio Zoom.V16 (Carl Zeiss, Germany). Seeds are from Mt. Malyi Sokol, Sudak territory Autonomous Republic of Crimea, Ukraine.