Texas Gardening: Texas Native Plant Pictures (Fern, Moss, Lichen & Mushroom), 1 by htop

htop wrote:
Chinese Brake Fern, Ladder Brake Fern, Cemetery Fern (Pteris vittata), Pteridaceae Family, naturalized, perennial, can be invasive

A terrestial fern, Chinese Brake has escaped from cultivation. It grows on almost any calcareous substrate, such as old sidewalks, masonry, building crevices, in crevices in limestone rocks, gorges, moist rock walls, streamsides, seeps and nearly every habitat with exposed limestone, notably pinelands in sun or shade (prefers sun). I could not locate any information about its county or regional distribution in Texas. Pteris vittata varies in size, overall color, aspects of the leaf and density of scales on the rachis. Its rhizome is stout, short, creeping and densely covered with matted reddish-brown scales. It has erect or arching fronds. The medium to dull green fronds and pinnules (leaves) are long and tapered giving it an open appearance. The rachis is 4-angled and covered with filiform brownish scales. The fronds 2-8 dm long. The linear-lanceolate, alternate, sessile pinnae (leaflets) are progressively larger from the base of frond to tip and have serrulated margins. They are 6 to 9 mm wide. The terminal pinna is linear-elongate and 5-25 cm long or longer. The veins multi-branched and the sori (are clusters of sporangia) are marginal, linear and continuous.

The problem of arsenic, a heavy metal, in soil is becoming more and more widespread because it is a by-product of many industrial and mining activities and has been a common component of weed killers and pesticides. Extensive research has been conducted and is being done on ways of cleaning soil. Research has found that Pteris vittata has the ability to extract arsenic from soil and store it in its leaves. In fact, most of the references about this fern that I found on the internet refer to this ability. The fern will seek it out and suck up the arsenic even where the arsenic concentration in the soil is low. Once the concentration of the heavy metal in the leaves is high, they can be harvested periodically for disposal in a safe facility. In addition, the ferns can be grown directly the water, similar to the reed-bed systems, where they remove arsenic as well.

For more information, see its entry in the PlantFiles:
http://davesgarden.com/guides/pf/go/58951/

Chinese Brake, Ladder Brake Fern (Pteris vittata) pinnae progressively increase in size toward the tip of the frond ... Photo courtesy of Forest and Kim Starr.