The Virtual Petrified Wood Museum.  Dedicated to the Exhibition and Educational Study of Permineralized Plant Material
Home Button
Science Button
Students Button
Fossils Button
Time Button
Tectonics Button
Taxonomy Button
Anatomy Button
Links Button
Contact Button
Bibliography Button
Paleozoic Drop Down Menu
Mesozoic Drop Down Menu
Cenozoic Drop Down Menu
Tree Fern Aerial Root

A cross-section of an aerial root found in the mantle of a tree fern reveals the central, star-shaped xylem. As the aerial root developed, primary xylem grew from five to nine different points. Metaxylem was then produced towards the center forming a star shape. Phloem tissue developed between the arms of the star. Cortical tissue and air spaces surround the xylem and phloem tissues. A sheath made of sclerenchyma cells enclosed the cortex. The root epidermis and cortical cells outside the rootlet proliferated to produce a dense mass of parenchyma tissue that held the root zone together.

The aerial rootlet pictured above comes from a permian-aged Brazilian tree fern (Titea singularis). The picture was taken at 30x. Below one can see the specimen from which the micrograph was taken. To view a series of images that zoom in on the individual rootlet visit the Brazil Gallery (slide 1) in the Permian section of our website.

Tree Fern
Titea singularis
Bieland, Maranhao Province, Brazil
Pedra de Fogo Formation
Permian

23 cm diameter
Close-up photographs of Titea singularis reveal plant tissues preserved in silica exhibiting beautiful pastel colors. The star-shaped xylem of the individual rootlets may conjure up images of snowflakes.
In the image above one can see adventitious roots from the inner part of the mantle. Proliferating epidermis and cortical tissues appear to "flow" around the individual roots which they interconnect.
The images below zoom in on vascular tissue found in the central vascular cylinder of the specimen above. Phloem can be found on either side of the xylem tissue.
 

©Copyright 2008 by Mike Viney| Website Use |