Botany Photo of the Day

Today's photographs are courtesy of David Smith of Delaware, who shared them via the UBC Botanical Garden Forums. It would have been more appropriate to show these a few weeks ago when David submitted them, but BPotD was running the abstract series at the time. Despite the seasonal relevance of this plant fading for another year, they're also interesting botanically, so here they are. Thanks, David!

Mistletoes, such as this oak mistletoe, are obligate hemiparasites – obligate, because they are obliged to do something, in this case meaning they are dependent on a host plant to complete their life cycle. If they could sometimes live and reproduce independently of a host plant, while at other times live the intriguing life of a parasite, they'd be described as facultative.

David's photographs show quite clearly why these are also termed hemiparasites. Strict parasitism, or holoparasitism, occurs when a parasite is entirely dependent on its host for all of its nutrients, minerals and water. Hemiparasites, on the other hand, do not entirely depend on the host. In this case, Phoradendron leucarpum is capable of its own photosynthesis (sugar production) through chlorophyllous leaves, while still parasitizing the host plant for minerals and water. Compare this strategy with Monotropa uniflora, if you're interested in an assignment.

Will Cook of Duke University shares a different interesting tidbit about Phoradendron leucarpum – a dispersal strategy that involves sticky pulp inside the fruit and birds.