We Walk Invisible

by Katherine King, Intern

Katie was recently chosen from eight finalists as our 2010 intern, sponsored by the Rotary Club of Shades Valley. From Bristol, Tennessee, Katie is a recent graduate of Samford University with a B.S. in biology--she has even studied botany in Belize (are you as jealous as we are?)! The internship gives a rising senior or recent college graduate hands-on experience with greenhouse production, planting, grounds maintenance, arboriculture, pest management, curatorial aspects of plant collections and garden display/design.

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As a youngster growing up in Tennessee, some of my fondest summer childhood memories involve running barefoot throughout my neighborhood with my siblings and other neighborhood children, and the repetitive calls of my mother to return home as the streetlights came on.  If we were lucky, we were allowed time to play “ain’t no bears out tonight” (a game similar to hide-and-seek).

Recently, I learned some intriguing folklore regarding bracken, a fern that is said to cover more of the earth’s surface than any other plant! Had I been aware of some of this plant’s reputed properties as a child, I most certainly would have tried to incorporate its fabled properties during play.  While researching this plant, I found bracken to be fascinating, and I hope you will too.

Bracken (also called bracken fern), Pteridium aquilinum, is a member of the Dennstaedtiaceae – the bracken family.  Its botanical name comes from the Greek, pteris meaning “fern” and the Latin, aquilinum meaning “eagle-like,” as the plant resembles an eagle’s wing.  Bracken’s hardy and robust characteristics allow it to grow almost anywhere; in fact it resides on every continent except Antarctica and in every biome except hot and cold deserts.  It has been found growing in soil pH from 2.8 to 8.6.  (2.8 is more acidic than grapefruit juice!)  Beginning with a single rhizome, the fern spreads vigorously, aided by its allelopathic properties.  These properties involve a plant’s ability to release chemicals into the surrounding soil, which inhibit or destroy encroaching plants. Bracken releases ecdysones, thiaminase, hydrogen cyanide, and tannins into the soil - thus stifling any plant competition.

Bracken is one of the most ancient ferns, with fossil records dating back to over 55 million years ago! Of interest is the major evolutionary change that took place with the advent of the ferns: the development of a vascular system. Before this, non-vascular land plants (specifically the mosses) were forced to remain small enough that they could stay in contact with the surface on which they grew. This enabled them to absorb water and nutrients across their cell walls. Ferns, because of their vascular “plumbing” were at a significant advantage because they were able to grow very large. Bracken is able to grow up to eight feet tall, though their usual height is two-to-six feet tall.

Bracken crosiers, left (image courtesy Better Photo, http://www.betterphoto.com) – a fern fronds’ coiled growth pattern as they emerge from the ground – frequently referred to as fiddleheads, were collected for food. Their edible uses included being ground into a type of flour or the roots being roasted to eat; in Asian grocery stores, the fiddleheads were sold as a delicacy.

Other ancient uses included bracken for constructing mildew-free thatched roofs in England, and as a bedding material for humans and livestock. Because the bracken fiddleheads resemble coiled worms, it was, in early times, believed that they could be ingested as a vermifuge…a remedy for intestinal worms.

Some of bracken’s folklore is timely, with the first day of summer (St. John’s day) fast approaching.  The possession of its miniscule spores were believed to render a person invisible. Thus by spreading the spores over one’s body, specifically on the eve of St. John’s Day, the person would become invisible. This belief was alluded to in William Shakespeare’s  Henry IV.

"We have the receipt of fern seed; we walk invisible."

If you have the occasion to become unseen, collect some spores and give them a try -  you never know when your next game of hide-and-seek will be… and bracken may just assure your success.

Bracken may be observed in The Gardens’ Fern Glade.