Ghosts in the Forest (and Other Parasitic Plants)

People think that it rains all the time in Seattle, but it's not true. Our summers can be hot and dry. So the tiny bit of rain earlier this week made many of us ecstatic - including, it seems, some of the plants, fungi and slime molds. We went for a hike on Tiger Mountain the other day, and in many places, the soil still seemed a little moist, and mushrooms had popped up here and there - far more than I expected to see in early August. 

Amanita mushroom

We also saw a beautiful pink pearl necklace of wolf's milk slime mold.

Wolf's milk slime mold

The coolest thing we saw by far, though were not mushrooms but the ghosts of the forest - ghost pipe or ghost plant (Monotropa uniflora). At first, we just found one lone flower.

Ghost pipe

Alert now, we kept looking and started seeing more and more clumps, which is how they usually grow.

Ghost pipe is a plant, but without a bit of green. It has lost the ability to manufacture chlorophyll and so can't photosynthesize. Instead, ghost pipes are beautiful but eerie-looking parasites. They use the fungal filaments in the soil (mycorrhizae, or the now famous wood wide web) to tap into other plants and steal nutrients from them - basically the plant equivalent of a vampire. Their nodding heads are still flowers, though; we even saw one being visited by a bumblebee. Other ghost pipes were starting to form fruits.

Ghost pipe fruit

Ghost pipes are not the only parasitic plants. Another cool example is the albino redwoods, which lack chlorophyll due to a genetic mutation. They parasitize nearby normal redwoods (sponging off of friends and family) to survive.

Some plants parasitize fungi directly, rather than using fungi to parasitize other plants. The fancy science term for this is mycoheterotrophy, which just means getting energy from fungi. The native orchid coralroot (Corallorhiza) is one such plant. We were too late for coralroot flowers on Tiger Mountain yesterday, but we did see their fruits (probably striped coralroot, based on their shape).

Coralroot fruits

Just for fun, here are a couple of other plants that parasitize fungi. We spotted these last year at Moran State Park on Orcas Island. 

Leafless wintergreen (Pyrola aphylla)

Pinesap (Hypopitys monotropa)

Any green you see in these photos are leaves of other nearby plants, not the pinesap or the wintergreen. Some wintergreens have green leaves (hence the name) but not this species. One of the fun and intriguing things about biology is that the rules for classifying life work - but only mostly! Plants are organisms that get their energy from the sun through photosynthesis - except when they don't! All these parasitic plants are presumed to have ancestors that were photosynthetic, so they still belong on the plant family tree. We just have to expand our concept of the plant family tree to include ghosts, parasites, and vampires!