Arceuthobium pusillum
Eastern dwarf mistletoe
Life History
Now we will follow the life history of the eastern dwarf mistletoe from being a fruit on the female plant, to being shot off like a rocket, establishing itself on a host and then reproducing to do it all over again.
The Journey of a Seed
When the fruits mature, usually around August or September, the seeds within them are rocketed out of the ripe fruit on thier new journey in life. On the seed itself surrounding it is a sticky substance called viscin. This allows the seed to stick to anything that it hits, be it another tree, a branch from the same tree, or an innocent animal passing by. For the case of simplicity we will assume that the seed came to rest on another tree branch. Once the seed is on the branch when it is moistened by rain the viscin becomes lubricant like allowing the seed to lodge itself at the base of needles on the branch. After the viscin dries it becomes a protective coating for the seed as it lays dormant throughout the winter season. Assuming the seed is not destroyed by insects or fungi it will germinate the following spring. This is the time when the little parasite develops its endophytic system within the bark and wood of the host tree allowing nutrients and water to freely flow to the plant. This all happens with no signs of infection nor aerial shoots of the parasitizing plant developing.
The Proliferation of a Parasite
Two years go by while the eastern dwarf mistletoe develops its internal root system anchoring itself to its host and drawing nutrients from it. At this time the host organism losses apical dominance around the infection site resulting in "witch's broom". It takes an additional two years before the first aerial shoots appearing giving rise to the flowers and fruit of the parasite.
Pollination of a Parasite
The Arceuthobium pusillum is diecous, meaning the male and female flowers are produced on separate plants. What is unusual about the eastern dwarf mistletoe pollination event is that the male pollinating structure grows first before the female. In many other plants the female flower matures first and readies itself for pollination before the appearance of the male structure. Though there is now specific organism that assists in the pollination process wind and a wide variety of insects help in this process of fertilization. This results in the female plant developing a seed-bearing fruit. And from there the cycle is complete and starts again when that plant explosively ejects that new seed.
Arceuthobium pusillum take about 5 years from first establishing itself on a host and disseminating its first seed crop.