Just recently, I uploaded to
http://salinevalley.topcities.com/pa...otsection.html an
image of a natural cross-section of a petrified palm root from the
late Miocene Dove Spring Formation (roughly 10 million years old),
California, a silicified specimen that reveals excellent preservation
of the epidermis, cortex and vascular cylinder (stele). For
perspective, the actual size of the specimen in the image is 5mm in
diameter. It's a species of palm, called scientifically, Palmoxylodon
mohavensis--named by Irma E. Webber in 1933; Webber compared the
fossil roots with those produced by the living Washingtonia and made
the following observation: "Since the Pliocene palm root differs
somewhat from that of Washingtonia, and since it was associated with
palm stems that differ markedly from those of Washingtonia, it is
referred to Palmoxylodon mohavensis, the species of palm represented
by wood in the deposits."

Not every piece of petrified palm root from the Dove Spring Formation
fossil locality revealed exquisite internal structure (the process of
silicification in many instances obliterated the finer details), but
occasionally one came across a natural cross-section that appeared
almost lifelike in its well-preserved fossil state. What's also
interesting is that Webber, in her scientific report regarding the
Dove Spring petrified palm locality, mentioned that fossil fungal
fruiting bodies had also been preserved in a number of petrified palm
roots.

(By the way, if you have trouble getting into the page, please try
again later. Sometimes I exceed my daily allotted bandwidth and my
server simply shuts me down for a short spell.)

Paleobotanical Field Trip To The Sailor Flat Hydraulic Gold Mine,
California
http://esmeralda.topcities.com/sf/sailorflat.html