By Sara Wright
Just the other day at Bucks Ledge Community Forest, I came upon large clumps of fading beech drops, less than a week after seeing others in bloom in another forest fragment. It is easy to miss these autumn blooming plants. The tiny rose-purple and white striped flowers are quite striking at close range, but they appear on the tops of small clumps just a few inches tall. Once the flowers fade, they look like a bunch of upright sticks and are easy to miss.
The key is to search for clumps in beech forests, the only place they grow. What’s very interesting to me is that, although I find clusters of these plants under beech trees, I don’t find them everywhere, and usually there are other trees mixed in even in beech forests. Last week I spent a long time searching for others besides the first clusters I found without success even though I was looking for them under what I perceived were the same general tree species, light conditions, etc.
Beech drops (Epifagus virginiana) bloom around here in September and October. The plants range from eastern Canada and Maine west to Ontario and Missouri and south as far as the Gulf of Mexico. Beech drops are annuals. The upper flowers are less than an inch long and are sometimes sterile. If they are not sterile, they are pollinated by bumblebees and ants. Bizarrely, some of these flowers may even develop underground. Those would have to be pollinated by ants. These upper flowers produce a bright yellow nectary (a nectar-secreting organ) to attract pollinators. On the stems the lower flowers do not open, but they are self-fertile. Interestingly, it’s the self-pollinating flowers that produce most of the seeds. The purple-tinged, yellow-brown ‘sticks’ also have scale-like ‘leaves’ and are somewhat furry around the base if uncovered. The fruits that form are capsules containing many small seeds.
These little wildflowers depend completely upon the beech tree for survival; they even need beech trees to germinate. The roots of beech trees release chemicals that trigger the germination of beech drop seeds. Once they have germinated, the developing beech drop attaches itself to a nearby beech root with a structure called a haustorium. The haustorium is a part of the plant’s root that penetrates the tissue of the tree to provide nutrients (sugars, water, etc.) because beech drops do not contain chlorophyll and cannot photosynthesize. The young seedlings begin to grow into the tissue of the beech tree roots to obtain energy and nutrients directly using the beech tree roots as their host. Most sources tell us beech drops are parasitic, but, because they are annuals, they do not harm the beech trees.
I am suspicious of the word ‘parasitic’ because the more we learn the more interrelated all plants seem to be. Most research indicates that between 80 and 90 percent of all vascular plants form a relationship with at least one species of fungi. Some species, called obligatory mycorrhizal species, require a fungus to live. Pinesap, another plant that also lacks chlorophyll, has a mycorrhizal relationship with white pines through which nutrients are exchanged (see Small Things September, Edition 22). Some species of plants do apparently manage to live without the help of mycorrhizae, but this is relatively rare. Could there be some mycorrhizal relationship also at work between beech drops and beech trees?
The word mycorrhizal requires further explanation. “Mycorrhiza” means fungal root. To be more specific, mycorrhizae are fungi that have a symbiotic relationship with the roots of one or many plants. There is always some kind of exchange. What interests me is whether beech drops may have this very specific mycorrhizal relationship, but it just hasn’t been discovered. With this question in mind, I did some extra research on the supposed parasitic nature of beech drops and found a couple of new academic studies that suggest that this plant might be mycorrhizal and not parasitic. This topic is just now being investigated.
According to a couple of sources, these plants are sensitive enough to local conditions and disturbances that their presence is used as an indicator of a healthy ecosystem. I know from my own experience that I am finding these clusters more frequently than I have before although I am still not seeing them stretch over an entire area of predominantly beech forests. Perhaps, I haven’t been in enough different forests to know. However, I am still wondering if the increase in rain and/or the increase in beech diseases or something else might be responsible for more plants and what this might mean for these fractured biomes overall.
A final caution: since beech drops will only grow at the base of beech trees and do not tolerate being separated from their host, don’t even think about transplanting one!
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