Fern Friday: Resurrection & PDT

Resurrection fern (Pleopeltis michauxiana) is a desiccation tolerant plant. During dry times, each resurrection fern frond “curls up” on itself exposing the underside of the frond which is covered with roundish (peltate) scales. These scales help to slow dehydration and aid in water absorption once moister times return.

Resurrection fern has another special adaptation to drought: It can turn off photosynthesis. This ability is called poikilchlorophyll desiccation tolerance (PDT). It is regarded as an anatomically complex strategy and is thought to be the “newest” strategy of desiccation tolerance. Interesting “newness” for a fern, the plants that reigned during the time of dinosaurs.

All ferns reproduce “primatively” via spores. The raised round structures are sporangia (spore cases). Only fertile (reproductive) fronds will be festooned with sporangia. The shape and arrangement of the sporangia often are used for fern identification.

Tiny spores, borne by the wind, are released by from the sporangia, and, if conditions are conducive, a new plant is born as seen below on the rock at he entrance to the Oslo Riverfront Conservation Area that. is beneath the Herb Kahle Nature Trail plaque (the corner of which is at the top of the photo) …

Once upon a time, the botanical name for this plant was Polypodium polypoidiodes. That was changed to Pleopeltis polypoidiodes. That name is now reserved for a small population of resurrection fern that grows only in the Florida Keys and has peltate scales on the top of the fronds, as well as on the bottom.

“Our” resurrection is now known as Pleopeltis michauxiana. The genus name, Pleopeltis, is derived from the Greek word pleos (many) and pelte (shield) referring the scales. The species name, michauxiana, honors 18th century French botanist Andre Michaux.

Whatever you call it, resurrection fern is miraculously adapted to dry conditions.

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