An unusual ferns in any collection, there is little detailed
information to be
found in English in any text regarding Microsorum thailandicum (tie-LAND-ee-cum).
Since the botanists who described the fern are Thai the majority of scientific information available is written in
that language. The genus name is confusing since on scientific
sites you can find both the genus "Microsorum" and "Microsorium"
containing ferns. The International Plant Names Index (IPNI),
ePIC (Royal Botanic Gardens, Kew, London) and The University of
Connecticut have this plant listed as Microsorum thailandicum.
The spelling "Microsorium thailandicum"
cannot be verified as a published scientific name through TROPICOS
(a service of the Missouri
Botanical Garden), IPNI, or ePIC.
Dr. Thaweesakdi Boonkerd and
Dutch botanist Hans Peter Nooteboom (Noot.) described the
species to science in 2001. Dr. Boonkerd is associated
with the Plants of Thailand Research Unit and holds a Ph.D. from the
University of Durham in the United Kingdom. The incorrect spelling (Microsorium
been used repeatedly by numerous websites and sellers on a
variety of websites.
Microsorum thailandicum is one of a
variety of blue strap ferns
known to science. There are
which also demonstrate this same coloration. Although
information easily found indicates the color is unique among
ferns, commerial grower Jay Vannini indicates,
plant´s color is not unique...several other Neotropical ferns
growing fern, it is relatively common in southeast Asia but is sometimes considered rare by
The tips of the fronds may be pointed but are often forked.
Even though the true genus is often confused by plant collectors, strap ferns are always included in the genus Microsorum, not
Microsorium by botanists.
Until recently, specimens were often difficult to locate and carried a high
price when available. Due to the
popularity of the unusual species it is now often sold by
terrarium and vivarium supply stores and the price is
reasonable. Normally, you will receive small immature
specimens but if you are willing to wait the several years for
the fern to mature the price is more than fair. However, you can still locate sellers on the
internet asking up to $100 for plants of more mature size. M. thailandicum
once commonly brought a
very high price, especially on sites such as eBay. One
moderate size eBay specimen attached to a piece of wood brought over
$100.00 in the summer of 2006. Growers in Asia now
export the fern in
large quantity causing the price to drop.
Not difficult to
grow, Microsorum thailandicum is claimed to be somewhat demanding if
you wish to maintain the cobalt blue coloration. Recent
information indicates this is not necessarily true.
According to growers in Thailand, this species,
with its 26 to 45cm (10 to 18 inch) fronds, exists in nature in the understory (the zone between the canopy
and ground cover plant forms) and appears to prefer both low light and high humidity.
But this fern has sometimes appeared to show even a "sub-understory" light
preference. Recently some growers have had excellent success
maintaining the color in very bright light. Although it will grow in
a variety of light conditions,
some growers feel if you grow the fern in dim light its
which can be forked (see inset left) can turn iridescent cobalt blue with a
metallic glow. Still others experience this blue coloration
in very bright light. This peculiar effect is found a
number of fern species in the world
and is especially noticed in the case of Microsorum
thailandicum when the plant is misted.
If not grown under good conditions when the fronds dry (in some
cases) they turn to a
less than iridescent green. If
grown well the fern will maintain the metallic blue
coloration at all times but is even more beautiful when moist.
There is however a difference
of professional opinion on how much, or how little, light these
ferns require to remain blue. Grower Jay Vaninni offered this explanation,
"I have dozens of sporing founders in a warm greenhouse that it
lit enough to grow, color and flower thousands of hybrid
Neoregelia bromeliads and the ferns look just fine. By the
same token, older plants in my personal collection at the house
grown in deep shade also look superb. They do appear to look
considerably better when watered with reverse osmosis or
rainwater and fertilized with very dilute fish emulsion and/or
kelp extract. There are many genera and species of metallic
strap-leaf ferns. México, Central and South America are replete
with montane Elaphoglossums like this."
fern species is both epiphytic (a plant that grows on another plant) and lithophitic.
In nature it may grow attached to
the sides of trees or fallen tree trunks or on limestone.
Knowledgeable collectors know Microsorum thailandicum as a
lithophyte (lith-a-FIT), in Greek meaning
"lover of stone". We now have a group of specimens attached
a log reproducing nicely (main photo) and a another group growing lithophytically
on limestone (see inset photo right above). A lithophyte
is a plant including some orchids that can grow with its roots
attached to stone and
derive nourishment primarily from the atmosphere. Microsorum thailandicum can be
induced to grow on limestone if you are willing to
spend the time to coax the fern's roots to attach. If you wish to try
this experiment for yourself read our explanation in the last paragraph of this
M. thailandicum grows
in the limestone hills of the
peninsula as well as Cambodia, Taiwan, southern China and
Vietnam. Our original fern was a gift from plant collector Windy
Aubrey in Hawaii.
Windy is considred an expert in the species by many collectors and recommends in to achieve the best color collectors grow the fern in
as low light as possible. Too much light (she insists) and the fronds will stay
green even though they will retain some of their
iridescence. Windy grows the fern in dark shade at all
times. Her recommendation is to keep the fern out of direct light as well as in a moist
climate due to its need for high humidity. Jay Vannini has
indicated in numerous email he has had just the opposite
experience with the blue coloration obvious evenin a greenhouse
with very bright light. Windy also states
emphatically this tropical needs a warm climate or a greenhouse since
the plant will not tolerate cool temperatures.
(spore cases) are
produced on the undersides of the fronds. Once released,
the spores can produce new ferns provided they attach to a viable
source. A photograph of
the sori can be located on the Plants of Thailand Research Unit
In addition to
reproduction via spores, Microsorum thailandicum
reproduces by putting out leading rhizomes once the fern is well
established. The majority of collectors utilize the later
method for species reproduction claiming growth from spores is difficult
to achieve. Once a new plant is set off by the parent it
can simply be removed by division.
The people of Thailand have a
common name for the cobalt blue fern, "waew peek maeng thub".
Translated from Thai that says "shiny as the wings of a scarab
beetle". That observation is apparently how the fern received one of its common names,
the Scarab Fern.
Numerous growers and sellers recommend the fern for humid terrariums. If you
elect to grow one in a terrarium or vivarium be sure and protect
it from strong overhead light in to enjoy the iridescence. We keep our dozen specimens near our pond's waterfall
where they receive dim light and a regular amount of spray.
However, we bring them indoors for much of the winter (misted
daily) because the temp in
the atrium can drop to 55 degrees F which is lower than this species
will tolerate and still flourish.
Since summer, 2006 we
have several of the blue ferns growing on limestone
and they are now attached. The
trick to making them attach to limestone is very high humidity and
frequent misting. If you wish to try this yourself you
may want to place your plants in a moderately lit vivarium or large decorative apothecary jar with
several inches of gravel in the bottom. Keep the the
bottom of the jar filled with water so the gravel is always wet.
This will insure high humidity inside the container. Place your limestone on top of the gravel
with your ferns attached to the stone. A single drop of
Super Glue will insure they not fall out of place.
Suitable pieces of limestone can often be found at
pet stores for use in aquariums. Remove the lid daily and
mist the ferns to replenish the air and moisture. Keep a lid on
the vivarium or jar to hold in the humidity and store the jar
in a dimly lit area of your home. Within a few months you
should see the roots of Microsorum thailandicum begin to attach. To insure good
growth be sure and mist the ferns daily as well as keep the root system packed with
damp orchid moss until you are certain the roots are firmly attached.
We often feed the fern with a very dilute orchid fertilizer.
If you are seeking information on other
rare species, click on "Aroids and other genera in the Collection" at the top
and look for the