What phytoliths can tell us
about early gardens
In 2012, when researchers from Washington State University
analyzed phytoliths found in a cooking pot from the ancient
Indus Valley village of Farmana, they discovered the remains of ginger
and turmeric that dated
2500 and 2200 BCE. More surprising, analysis from three
other Indus Valley sites found phytoliths from bananas, which
until then were believed to have been unknown in this part of
the world until the late Middle Ages
(Science, 7-20-12, p.288).
Clearly, phytolith studies such as these are transforming our understanding of the past.
What are phytoliths?
phytolith comes from the Greek words for plant (phyto)
and stone (lithos). Phytoliths are tiny silicate bodies
that survive the decay of softer plant tissues.
dioxide, is a
compound that dissolves in
ground water. Some plants take up silica, along with water,
through their roots. The silica is deposited in plant cells, and
takes the shape of the cell or of the spaces between the cells.
Since silica is remarkably durable, it may survive after the
soft tissues of the plant have decayed.
When the plant is
eaten, or burned, or dies and decays, the phytoliths survive,
and are found in many places -- in the soil,
in dung heaps and trash piles, inside cooking pots, and even on teeth.
In some plant remains, phytoliths
preserve shapes that are so specific they can be used to
identify the plants from which they come. Environmental
archeologists and archeobotanists can use phytoliths to identify,
with varying degrees of precision, the plants
that grew at a site,
were eaten by a person or animal, or were cooked in a pot.
important because, until the 20th
century, humans used plants to create most of their
“material culture” -- buildings. furniture, art, fuel, clothing,
medicine, food. Unfortunately, the portions of plants and their products
that we would have liked to study were usually too
fragile to survive the elements. As a result, our knowledge of
cultures had, of necessity, centered on more permanent
artifacts made of bone, stone, ceramics, and metals. Careful
analysis of phytoliths, in combination with other research,
is allowing us to broaden this focus.
Do all plants produce phytoliths?
No, not all plants produce these
silicon markers. Plants that DO produce phytoliths include: