PLANT OF THE WEEK

Dr. T. Ombrello - UCC Biology Department

RESURRECTION PLANT

Common names:  

Resurrection Plant, Rose of Jericho, Siempre Viva (meaning Everlasting)

Scientific name:        Selaginella lepidophylla

Explanation of scientific name:       

Selaginella      - from the Latin "selago" (A type of juniper we now call savin juniper. Selaginellas have juniper-like foliage.), and the Latin "ella" meaning small.

lepidophylla    - from the Latin meaning scaly-leaved.  

The Resurrection Plant is one of over 700 species in the Selaginella genus of plants. All of them are primitive plants, fitting somewhere between mosses and ferns in the hierarchy of plant evolution. They belong to a group of plants known as the lycopods, whose members go by the common names of ground pines and club mosses. All are relatively small (up to one foot tall) and are found around the world, usually in moist locations with mosses and ferns. They reproduce by single-celled spores, and lack flowers, fruits and seeds. Even their "leaves" are not really leaves, but instead leaf-like extensions of the stem. What lycopods consist of then are roots, stems with scales, and club-like strobili that produce spores.

What distinguishes the Resurrection Plant from most other lycopods is where it lives and how it copes with its environment. Found from Texas and Arizona south to El Salvador, the Resurrection plant is a desert inhabitant. Growing from rock outcroppings or in dry soil, its close neighbors would be mostly cacti and other arid-loving species. Under these conditions, most other lycopods would perish, but the Resurrection Plant thrives.

When the soil is moist after infrequent rains, a Resurrection Plant absorbs water and grows rapidly, producing a flat rosette of scaly stems up to one foot across. As the soil dries, it cannot store water like its succulent neighbors, so it folds up its stems into a tight ball as it desiccates and goes into a state of dormancy. The folded plant has a limited surface area, and what little internal moisture is present is conserved. All metabolic functions are reduced to a bare minimum and it appears to be dead. The plant can remain in this dormant condition for years. When the rains return, the plant's cells rehydrate. The stems unfold, metabolism increases, and growth resumes. Even dead Resurrection plants will unfold if given water, since rehydrated cells expand even if there is no living protoplasm in them.

The Resurrection Plant's ability to seemingly return from the dead certainly justifies its common name, and has led to its use as a novelty plant. Collected from the wild in the South West US and Mexico, it is sold to tourists and exported worldwide.

As a lycopod, the Resurrection Plant can trace its ancestors far back into history. They appeared at least 400 million years ago as small plants similar in appearance to those that are alive today. Their period of prominence however, came later. Between 345 and 280 million years ago they dominated the plant world as giant trees over 100 feet tall with trunks 6 feet in diameter at the base. These swamp inhabiting trees became important contributors to the coal deposits we exploit today. Cooler climates and other as yet unidentified factors caused these giant lycopods to become extinct. But their smaller relatives, like the Resurrection Plant, persisted in a changing world.