Species in the Collection
Rainforest Tour
Orchids
The
Exotic Rainforest
Images on this website are
Copyright protected. They are not in the public domain! Contact
us before attempting to reuse.
Within our collection we have many species of Anthurium. If you are seeking other photos, click this link:
Growing the Tropical Anthurium
Where
Anthurium live in nature,
Anthurium
care, how to cultivate, grow,
pot and water an
Anthurium including information
how
Anthurium
species grow and reproduce in the
rain forest.
Despite what some growers
claim
scientifically not one of the nearly 1000
species grows in water!
This
text was written and all photography (unless otherwise noted) was
created by Steve Lucas,
www.ExoticRainforest.com
Although
as non-technical as possible much
of the information on this page is based on the scientific journals
of my teacher and mentor aroid botanist Dr. Thomas B. Croat
Ph.D., P.A. Schulze Curator of Botany
of the Missouri
Botanical Garden in St. Louis, MO. Dr. Croat was honored in
the summer of 2008 for having collected over 100,000 specimens in
the wild. My thanks to aroid expert Julius Boos, aroid, palm
and cycad expert Leland Miyano and expert aroid grower Russ Hammer
for their input into this article. And my sincere thanks to
Dr. Croat for his continued guidance as well as almost
daily personal communication.
A serious effort has been made to keep this information non-technical but scientifically accurate.
There are published estimates
of the internet of approximately 800
botanically described species of Anthurium currently
known to science. In a private meeting with my friend
esteemed aroid botanist Dr. Thomas B. Croat on Friday June 20,
2008 at his offices at the Missouri Botanical Garden in St.
Louis, MO, Dr. Croat brought that estimate up to a more accurate
number. The current best estimate is closer to 1000
species as a result of many finds of new species in South
America, especially Ecuador. Dr. Croat's credits
are listed above and he is recognized as the world's leading
authority in the genus Anthurium. Of modern
experts, Dr. Croat has discovered, named and described more
species to science than any other botanical authority having
personally collected more than 100,000 plant specimens in the
wild.
Aroid botanists know there may be an equal number of
unidentified species still not located and described in the rain
forests of many South American countries, including Ecuador and
Colombia. The vast majority of the rarest and most
beautiful forms are located on the western slopes of the Andes
Mountains and within the rain forests of Ecuador. Those species are
also widely
variable and it is not uncommon for a single species to produce
more than one leaf form. You can find an explanation of "variability"
here:
Click this link.Despite an increasing number of articles on the internet which appear to claim up to fifty Anthurium species are found naturally in Southeast Asia, scientifically none are natural or endemic in that part of the world. One internet "encyclopedia" appears to be the source of this dubious information. Aroid expert Julius Boos explains, "Anthurium is a neotropical genus and does not occur naturally anywhere outside the neo-tropics!" The neo-tropics is defined as South and Central America. Any Anthurium species found in Asia, the South Pacific, or Indonesian rain forests would have to have been introduced by plant collectors. These
species are not found
naturally in these regions of the world. Julius'
information is verified in many of the published papers written
by Dr. Croat (CROWat).The genus Anthurium is now found in many South Pacific islands, but only as an introduced species. In Hawaii, many species can be found currently in cultivation since the genus is used to hybridize many hybrid variations which are commonly sold in garden centers However, all were introduced into Hawaii and none live their naturally. Anthurium species are members of a larger family group known as Araceae (aroids) and there are in fact members of the larger group known as Araceae found in SE Asia but these do not include Anthurium or Philodendron species. For further scientific reference, please read this work by Dr. Tom Croat: http://www.aroid.org/genera/anthurium/abstrap1.htm
these new species.
Some are so beautiful and odd, they defy belief. 
features are known as the geniculum and the collective
vein and can be seen on any Anthurium specimen. The
geniculum is located at the top of the petiole and allows the
leaf to rotate and orient in order to better collect sunlight.
The
collective vein is found very near edge of the leaf blade. 
As you will observe the petiole is what
most
people
would call a "stem", however the true stem is located at the
base of the plant and the petiole connects the leaf blade to the
stem. The stem at the plant's base collects and stores
water and nutrients absorbed by the roots. In many
Anthurium species those roots never touch the soil since
many species are suspended on the trunk or limb of a tree!
The petioles then transfer the water and nutrients from the stem
to the leaf blades. The blades then convert carbon dioxide
in the air into oxygen for other living organisms such as humans
to breathe. The geniculum looks and works something like
your knee or elbow. Just like your elbow allows you to
bend and rotate your arm, the geniculum allows the leaf of an
Anthurium to rotate itself up, down or from side to side in
order to better collect light. The geniculum may be
swollen and obvious in some species but barely noticeable except
to the touch in others. It is not uncommon for the
geniculum to have scars from age.
The
collective vein is found at the perimeter of the leaf blade and
the primary lateral leaf veins connect into the collective vein.
The collective vein completely encircles the leaf in some
species but in others begins approximately 1/3 down from the top
of the blade and emerges from one of the primary lateral leaf
veins and then runs to the bottom of the blade and up the
opposite side to reconnect with a primary lateral leaf vein on
the opposite side of the blade. These two features
combined are unique to Anthurium species although other
plants by have one or the other. Neither will ever be seen
in a Philodendron species and is often used as a
determining factor to decide if a plant is an Anthurium
species or a Philodendron specimen.
their DNA combined the newly produced
specimen is no longer either species! Instead, it is
simply a hybridized offspring. Still, growers often
attempt to sell these offspring as a
new "species" with some unique "made-up" name not recognized by
scientists or botany. Another popular Anthurium
which is often confused is Anthurium hookeri. For
years growers in Florida have assumed a commonly available
hybrid was truly the species! But in fact, the species
looks nothing like the hybrid and produces very unique leaf
blades along with white seed berries (not red). So unique,
botanists are now considering the possibility of giving that
species its very own section which will make it unique among the
birds nest forms.
Click here to read about Anthurium
hookeri. You
can find photographs and information on all the species in our
collection by clicking on this link:
Species in the ExoticRainforest
Collection. 
As
a result of the interest in Anthurium, questions via
internet search engines regarding Anthurium species are
frequently asked. One popular question often typed into
an internet search engine is asking in one form or another "How
do I grow Anthurium species?", "How do I pot an
Anthurium?", or they ask about the care and culture of some
Anthurium species. Two truly strange questions are
"Can I grow an Anthurium in water?" and "Name all
aquatic Anthurium species". According to Dr.
Croat, there is no such thing as an aquatic
Anthurium. 
Anthurium from another genus. A simple yet positive
way to tell them apart is to look for the small swelling,
or bump, on the petiole at the point where the blade attaches to
the petiole (stem). On any Anthurium
there will be a swollen area known as the geniculum. That
"bump" will not be present on a Philodendron
nor an
Alocasia. The geniculum is thicker than the petiole.
Aroid expert Julius Boos explains further regarding the purpose
of the geniculum,
"
the geniculum acts like a ''wrist'', and actually allows the
leaf blade to turn or rotate to align itself with the light
source and occurs only on some aroid genera including Anthurium
and Spathiphyllum but not on others."
inflorescence known to science as a spathe which is
in fact a modified
leaf.
The inflorescence,
which is sometimes shaped like cupped hands is made up of
several parts. Chiefly the portion that appears to be a
"flower" is the spathe and inside that is the spadix which
somewhat resembles an elongated pine cone. Many people
think the spathe is the "flower", but technically, the tiny
flowers are found on the spadix at the center of the
inflorescence. The male flowers produce pollen and the
female flowers can be pollinated with pollen brought from
another specimen by a beetle from the genus Cyclecophala. Once the flowers on the
spadix have been fertilized they will eventually produce berries
which can range in color. When in fruit the entire
structure is known to a scientist as an infructesence.
other group the male and
female flowers occur mixed closely together throughout the
entire length of the spadix."
The tiny
male flowers produce pollen and the
tiny female flowers are
designed to be
receptive to pollen. However, most are cleverly divided by
nature to keep the plant from being self-pollinated.
Once the female flowers have completed
anthesis the
male flowers begin to produce pollen. Most Anthurium
produce their pollen acroscopically which simply
means towards
the apex (top). But in a select number of species the
pollen is produced from the top of the spadix downward.
That event is rare and is known as basioscopic pollen production
as in those with thumb-shaped spadices.
Nature's preferred method is to have insects (almost always a
Cyclocephala beetle) pick up the pollen from one plant and
carry it to the female flowers of another plant in keep the
species strong. Still, in a few species self pollination
is possible. If you collect and process the seeds properly
you can easily grow new plants. There is an estimated 900
species in the genus
Cyclocephala and only approximately one half are
identified as species by science.
The
majority of aroids require a specific insect to do the work of
pollination. If that insect is not present, it is unlikely
the plant will be pollinated naturally. If pollinated by
that "assigned" insect, the spadix can produce fruit which can
vary in color from red to orange, purple, green, white, or shades of
these colors. Eventually the fruit ripens and contains
very small seeds. Those fruit are how the Anthurium
reproduces itself once a bird, rainforest animal, or bat eats the fruit or a seed falls to
the ground. The birds and animals spread the seeds thought
the jungle and place them on the branches of trees in their own
droppings. Anthurium
species can also reproduce from divisions, but it is not
possible to propagate them by planting leaves!
Simply trying to
pot a leaf won't grow anything! There are a very few
aroids including Zamioculcas zamiifolia which can reproduce by planting leaves, but Anthurium
species are not in that group.
If you are interested in how the beetles are attracted to the Anthurium please read the information from aroid pollination expert Marc Gibernau at the end of this article.
Should you plan to grow your
own Anthurium seeds do not pot them in soil!
Instead, gently squeeze the seeds out of the mesocarp pulp of
the berry into a jar with clear sterile water and shake the capped jar well to separate the pulp from
the seeds. In a couple of days the seeds will settle to the
bottom and the pulp will rise to the surface so it can be
removed. Remove the seeds and put them in a clean jar of
water and shake once more to remove any traces of the pulp which
can cause the seeds to produce a fungus. Prepare a shallow
plastic container (such as a restaurant salad container) by
cutting long strand sphagnum moss into very short fine pieces, mix in
approximately 1/4 aquarium charcoal and press this fine mix
into
the bottom of the container. Do not add any soil! Be sure and punch drain holes
in the container's bottom before filling and do not allow the
container to hold water!! The goal is to have a high
humidity environment in which the seeds can germinate. You need no more than 1/3 of the
container to be filled with the moss growing bed which will now be similar
to the floor of a rain forest. Spread your seeds (evenly
spaced) across
the surface and mist them lightly with either rain water or
bottled purified water. Do not attempt to cover or bury
the seeds! Put on the lid of the container
and you now have a miniature greenhouse. Store the seeds
in moderately filtered light in a warm room and in two days to
a week you will see germination. Mist only as needed. Continue to grow the
plants with the lid on and just mist them lightly
until they are well developed and then transplant them to fast
draining soil which contains peat moss, shredded sphagnum moss,
hard wood charcoal (such as aquarium charcoal) and high quality
potting soil in roughly an equal mixture. In a year or two you'll have
nice specimens to
display or give away.
Botanists
divide
Anthurium species into "sections". Those sections
are used to categorize the various leaf and plant structures into
specific groups. As an example, section Cardiolonchium
contains the species with leaf surfaces that are velutinous and
both feel and look like "velvet". This
group is particularly beautiful and contains many of the most
sought after species of Anthurium. Well known
members of the section include Anthurium regale, Anthurium
crystallinum, A. magnificum and A. warocqueanum.
Frequently collected species are sometimes known as "birds nest"
forms. That group is section Pachyneurium. The
largest specimen of this section in our collection is
Anthurium
schlechtendalii and is capable of producing leaves 6
feet long or longer (see photo, top of page). Other
interesting members of this section include
Anthurium
salviniae
and
Anthurium plowmanii.
But there are
numerous other sections of
Anthurium species.
ground. Even many of gigantic "birds nest" forms (see
photo left) grow on the limb of a tree not in the soil!
The ones that grow on trees are scientifically known as either
epiphytes or hemiepiphytes. An epiphyte is a plant that
simply grows upon another plant, normally a tree. The seed
berries, once eaten and digested by a bird, are then left on a
tree branch in the bird's droppings. Those seeds find just
enough nutrient substances in the droppings to germinate and
begin to grow on the limb of the tree. Some eventually
drop roots all the way to the soil and as a result,
once they
pick up extra water and nutrients, grow quite large.
Others begin life in the soil and then climb the tree.
Those are known as the hemiepiphytes. But keep in mind, an
Anthurium is not a parasite, it is an epiphyte. It
simply uses the host for support.If you plan on growing an Anthurium it is wise to first learn just how the species you possess grows in nature (assuming it is a species) and then try to duplicate that condition as best possible if you wish to experience the natural beauty and full growth potential of the specimen. One major problem with figuring out what species of Anthurium you are growing is caused by a phenomenon known to a botanist as "variability". Most people assume that just because many trees have the same type of leaves, that all species of Anthurium should also have identical leaves. In aroids, that is simply not the case. Think of it as human beings all having different "faces". There is only one species of humans, but numerous "faces". An Anthurium species can also have many "faces".
Not only do the leaves vary
from species to species, they can vary (morph) in the same plant
as the Anthurium ages. And in the same way all
human bodies don't look alike (tall, fat, short, skinny),
neither do all Anthurium, even from the same Anthurium
species! An Anthurium species is easily capable of
assuming many leaf shapes and sizes, and they
often
"morph" as they grow just as a child changes as it changes from
a child to an adult. They increase in size and
change shape from a juvenile stage leaf to that of an adult
stage leaf.. .To
a botanist, it is simply "variation". But as you can
easily see from the few photos on this page, an
Anthurium has no set shape! Some are oval, some are
spear shaped, some are shaped like a heart, some feel like
leather (known as coriaceous), and many have leaves that feel
like velvet. This concept is often difficult for plant
collectors to accept. Aroid botanists and those of us who
are serious collectors receive mail all the time insisting any
leaf with a different shape simply MUST be a different species.
That is simply not the case. Think of your father, your
grandfather, and your uncles. They are the same species
and from the same family, but they don't look exactly alike!
Any Anthurium
species is the same way.Many Anthurium plants commonly sold at nurseries are likely hybridized plants and not species. A hybrid Anthurium is one where each of the parents
was a different species. But in the
case of hybrids, each parent may have also been a hybrid itself.
Thus, you may have the genes of numerous plants involved in
creating that hybrid. You'll just have to believe what
some retailer/grower tells you, and that may often be wrong,
since scientifically correct information on hybrids is rarely
available. Hybrid Anthurium are created when the
pollen from one species is applied to the spadix of another
species at the time the plant is ready to reproduce. The
resulting seeds are neither species, but a hybrid form of the
two. Some hybridizers enjoy seeing just what they can
create and after a period of time you have no idea what the
parents actually may have been. As a result, there is no
way of knowing if the new hybrid prefers really wet conditions,
drier conditions, cooler condition, grows in the ground, or high
in the trees. Although hybrids can be beautiful, my
preference is to grow only species which can be traced back to
their natural habitat and thus better understood. But
there are also natural hybrids that occur in nature which can
add to the confusion. 
The
majority of Anthurium plants you are juvenile forms and
look nothing like the adult form of the species. Remember,
they "morph" as they grow! For many years botanists were
confused by the drastic differences in adult forms and juvenile
forms and often tried to give them each a different scientific
names. That is one reason some plants have numerous
scientific names which can be worked back using a source such as
TROPICOS (a service of the Missouri Botanical Garden) to a
single basionym (primary species name). You need to learn
all you can about your Anthurium species, and that is one
thing, with the help of Dr. Croat and numerous aroid experts, I
attempt to help you do on this website.If you live in a tropical or semi-tropical climate you can simply put your Anthurium in the ground. If it is an epiphyte it may try to climb a tree. If it is a terrestrial form, give it plenty of room. Many of the "birds nest" species love to spread and can eventually grow leaves 6 feet long or longer creating a very large specimen! But remember, those may also grow up on the limb of a tree in the rain forest! Otherwise, proper potting of your specimen is very important if you want it to both survive and grow to reach the full natural beauty.
I
can't remember how many people I've seen go into a garden store
and a buy very rich potting soil that stays soggy all the time and
then kill their Anthurium. They literally drown
it! For some reason people believe the rich soil makes an
Anthurium grow better! Typical off-the-shelf "potting
soils" just don't work for Anthurium species!
Remember, these species often grow in trees, not in wet soggy
soil. Their roots are designed to collect rain water
almost daily during the wet season and then suffer through the
dry season. But even in the dry season they can collect
enough water from the humidity around their exposed roots in to
survive. Again, you can make your plants grow much more
beautifully, and stay healthier, if you try to learn all that is
possible about their natural habitat.
If
you are growing a truly epiphytic species, you may not wish to
grow it in soil at all! Some sellers provide them attached
to volcanic rock. There are species known to be epipetric
which simply means they grow on stone. Anthurium bonplandii
shown near the top of this article is one of those species.
Volcanic rock can work, provided you keep t
hose rocks constantly
damp and filled with water. The plant will extract the
necessary water from the interior of the porous rock. That
does not mean to sit the plant in water! Just keep the
rocks wet. No Anthurium species is known to grow in
water despite what some websites and seller try to make you
believe. This technique can be difficult since most
growers rarely remember to wet those volcanic stones every
single day.
If you feel you must plant
the Anthurium in soil, especially if it is known to be a
terrestrial form or "bird's nest" species, rather than using a
rich, soggy soil and watering only once a week (or less), use a
soil that holds moisture well but
drains very quickly. That is what the plant actually needs
and prefers in most cases. In fact the
majority
of section Pachyneurium species require a period of dryness in
the forest in order to prosper! Be aware that far more bird's
nest forms which are all members of Anthurium section
Pachyneurium grow up in the trees rather than in soil! 
Although we mix our soil based on how the species grows in
nature, we primarily use 30% Miracle Grow Potting Mix combined
with 30% Peat Moss, 20% orchid potting media with hard wood,
charcoal and mineral containing gravel and 10% Perlite™, and the
balance cypress mulch along with finely cut spahgnum moss all
thoroughly mixed together. We also add extra hardwood
charcoal on the advice of the aroid keepers at the Missouri
Botanical Garden. We grow close to 50 different species in
this mixture and numerous specimens have reached, or are
beginning to reach, their adult or near adult size and have
produced inflorescences. The purpose of our mixture is to cause the water to flow through the soil quickly, yet stay damp, not soggy. Many growers call this type of mixture a "jungle mix" due to its similarity to the soil in a rain forest. The peat, orchid medium, charcoal, mulch, sphagnum and Perlite™ hold moisture and release it back to the roots as needed. And the extra charcoal purifies the soil and keeps the mixture very loose. The roots of the plant will also attach to the bark just as they do in nature on the side of a tree. Depending on the species, we sometimes also add small pieces of crushed volcanic rock frequently sold in orchid supply stores. We use volcanic media since the roots will often attach to the rock and extract stored water. Volcanic rock is known to absorb water and hold it for a moderately long period of time.
I've had several "nursery experts" write to tell me my soil
mixture won't work due to the orchid potting media and mulch.
They claim the bark and mulch will eventually rot and create air
pockets in the soil and then kill the plant. They need to
tell that to the experts at botanical gardens such as the
Missouri Botanical Garden in St. Louis which maintains one of
the world's largest collection of Anthurium since they
developed the mixture. Botanical gardens in Florida,
Europe and other parts of the United States us a similar mixture
for almost all aroids. We've been using it since 2003 and
our Anthurium
as well as Philodendron species just keep growing!
If the wood is decomposing, and it probably is, it appears to
simply become part of the soil the same way it does in any rain
forest. The principal reason this mixture works is the
soil stays aerated and loose. It holds enough water, but
will not stay soggy. That is precisely what most
Anthurium species need.The next important consideration in Anthurium care is light. In almost any rain forest, light is a very precious commodity! Plants fight for position and large ones often deprive small specimens of almost any light at all! That is the exact reason Anthurium, and other species, are climbing a tree. They are trying to reach the light! As they grow high
on the side of the tree
botanists see that almost all morph into what often appears to
be a totally different species! But in reality this new
morphed "form" is just the adult leaf shape of the juvenile
plant. Almost all Anthurium species prefer bright
indirect light. Some will live in deep shade, but many
will not flourish. As a result, don't try to grow them in
a darkened corner of your living room. Keep them near a
window with brighter, but diffused light. Some can be
trained to live in very bright light, but very few will survive
in direct sunlight. As a result, if you are growing your
Anthurium species outdoors, keep them close to a tree that
will allow for filtered sunlight.
There are species that prefer
a longer dry period including all the Birds Nest types and we attempt to segregate those during the
winter season. Section Pachyneurium species (Birds Nest
types) must have a dry period and often go for a month or more
with no water at all. These species actually must
have the dry period in order to remain vialbe. But remember
most Anthurium species grow in a
rain forest, not a living room! It often rains daily in
the "rain forest" for 9 months or more per year!
Most prefer to have their roots damp all
the time, just not in soggy soil. In your home, water
often enough to keep the soil damp, but not soggy. Make
sure the pot can easily drain. If you use a pot with
no drain holes in the bottom, then add a minimum of three inches
of gravel (non-limestone) beneath the soil mix so the water can
drain from the soil. We attempt to explain the
details on individual species on each of our web pages.
And this website has well over 300 pages of information!
Go
to this link for a list of 75% of our species.
More pages are being
added each week.What about fertilizer? In nature an Anthurium receives only natural forms! The epiphytic species can collect minerals in the rain which comes from the winds blowing across the Atlantic from Africa. They often bring dust from major dust storms in the African plains to the rain forests of tropical America. Once it settles in the rain the long dangling roots of the plants do gather a small amount of dissolved minerals and nutrients. But nothing like home growers are prone to offer! Even the species up in the canopy often collect falling debris in the form of dead leaves and convert that to a
natural form of fertilizer. Temperature? Virtually all Anthurium species are tropical. That means they just can't tolerate really cold
temperatures.
Some do live high in the Andes Mountains well above the cloud
line. As a result, these are "cool" loving species.
But not cold! The cloud forest species don't like heat and
won't do well in an outdoor setting where the temperature may
stay above 26.6C (80 degrees F) for long periods of time.
They can tolerate short spells of high temperatures, but some,
such as
Anthurium rugulosum, (photo left) may not survive.
Many growers of these cool loving species use a high humidity
"wet wall" combined with a small air conditioning system to keep
the ambient temperature low and the humidity high. Many of
these species will do well down to 4.45C (40 degrees
Fahrenheit), but not much cooler.
As a general rule, never
allow the temperature around most of your Anthurium
specimens to drop below 12.75C (55 degrees F). It is
best to keep them well below 32C (90 degrees F) which is not
particularly difficult if you grow them in some form of shade or
filtered light. Some species will tolerate short periods
of cold, such as Central Florida. But most won't survive
anywhere outdoors north of Zone 9. Zone 10 is best!
Many will simply die if exposed to a freeze. And since
most show much faster growth when the temperature is in the 21
to 29.5C (70 to 85 degree F) range you may find your specimen
will appreciate being allowed to live outdoors during the
spring and portions of the fall.Humidity is extremely important! Do everything you possibly can to keep the humidity high around your Anthurium. These species live in a jungle which can have a humidity level near 100%! If you live in a climate that has a low humidity, like southern California, then you'll need to provide a method of giving the aroid more humidity. In our rain forest the humidity is always high (85% or higher) due to the pond in the center of the room and frequent water! Some growers keep their Anthurium species near a swimming pool to allow for a constantly high humidity. Air circulation is equally important since the air is almost always moving in the rain forest. Avoid stagnant air since that may encourage insect predators.
f you can't give the species rain forest humidity conditions then there is a simple alternative. an attractive shallow dish that can sit beneath the plant's pot. Fill that pan with gravel, preferably one that does not have too much limestone. Fill the pan and gravel with water and then sit your plant and pot on top of this gravel bath in to create a micro-climate around the Anthurium. Promise, it works! Water will evaporate around the leaves all the time and fool the plant into believing it is living in a humid rain forest environment. And when you water, the excess will simply drain into the gravel pot.
Why do you want to avoid limestone gravel? If you use the soil mixture we suggest, you've just created a soil mixture with a pH below 7, likely around 6.5. The Anthurium will appreciate that pH level! If you add limestone to the mix, the pH can be raised to above 7 and the Anthurium is not as likely to appreciate that level with the exception of a few species which do live in higher soil pH areas of the tropics.
Growing
and the care of
Anthurium species is
not difficult. Only a few are hard to grow, and most will
grow fairly well under a wide variety of conditions.
Remember, they often begin on or near the rain forest floor in
relatively low light and spend years climbing up to the light
level they have been seeking. The keys are allowing the
epiphytic forms to climb, giving the spreading types room to
spread, fast draining soil that stays damp, dry for only short
periods, a stable
temperature, good air circulation, and good light that is
relatively bright. It's just that easy!
inflorescence, there are very tiny flowers and they are found on the spadix at the center of
the inflorescence. The inflorescence, which is sometimes
shaped like a tube, is made of several
parts. Chiefly the portion that appears to be the "flower" is
known as the spathe and inside that is the spadix which
somewhat resembles an elongated pine cone. When ready to reproduce, the spadix produces both male, female
and sterile male flowers which are used by natural polliantors as
food. In addition, these sterile flowers produce a scent which
attracts those insect pollinators. The tiny male flowers produce pollen and the
tiny female flowers are designed to be receptive to pollen.
Many, but not all, are cleverly divided by nature to keep the plant from
being self pollinated since the male flowers don't always produce
pollen at the same time the female flowers are receptive. Nature's preferred method is to have
insects pick up the pollen from one plant and carry it to another
plant to keep the species strong.
The majority of aroids require a specific insect to do the work of pollination. If that insect is not present, it is unlikely the plant will be pollinated naturally. In the case of Anthurium species that insect is almost always a small beetle within the genus Cyclocephala. If pollinated by the male insect and its mate the spadix can produce fruit as explained earlier. That fruit contains the seeds and is how the Anthurium reproduces itself once a bird, bat or animal eats the fruit or a seed falls to the ground. The animals disperse those seeds within the fruit in their own droppings.
Anthurium sp. are often visited by the male of the appropriate Cyclocephala beetle species and his mate. There is another genus of smaller beetles known as Neelia that visit Anthurium species but these beetles do not appear to feed
nor mate on the inflorescence. It
appears Cyclocephala beetles do almost all the work of
pollination.
Some of these beetles are not particularly species specific and
visit more than a single Anthurium species, however
it is surmised that since Cyclocephala beetles prefer to
fly at a specific height from the ground they avoid an plants
not normally found in their "altitude" range. the height of the plant may be a particular
attractant to individual beetles thus causing them not to cross
pollinate other Anthurium sp. than their specified
species.
The beetles are generally drawn to the Anthurium inflorescence in the late day or at dusk and are attracted by a combination of pheromones (scent) and a source of food and shelter which is composed at least in part of an oil produced on the staminate flowers containing lipids along the spadix.
can warm enough to be noticeable to the touch and for
the insects that may be tired from traveling long distances to
perform their required tasks this additional source of heat in
the rain forest creates a microclimate and may actually increase
their metabolism and encourage them to explore all portions of
the spathe and spadix. A microclimatic zone of warmth is now
being generated that offers both comfort and
protection along with food. 
The thermogenesis
(thermo genesis. "Heat Birth" or
heat production) caused by the salicylic acid
appears to be one of the stimulators to cause the beetles to be
active and as a result to both feed and copulate. It is known
the rate of thermogenesis (heat rise) is sometimes
dramatic. However, thermogenesis does not produce a consistent
temperature since the highest temperatures appear to last only
a few minutes. The presence of beetles appears to increase the temperature
produced by the event. The temperature increase appears to
increase the amount of pheromone (perfume) being exuded by
the tiny flowers, thus the strength of the pollinator
attractant. The first stage of
anthesis is when the female flowers are ready to be pollinated
and the production of the attractant pheromone along with
thermogenesis begins. Female anthesis in Anthurium
sp.
can last approximately 2 days.
A more recent train of thought includes the possibility of
infrared heat as an increaser to the production and distribution
of these pheromones. My friend aroid
pollination expert Dr. Marc Gibernau created and provided the
chart below. His chart shows just how "bright" the "glow"
of infrared heat is the the pollinating beetle as well as
indicating the increase in temperature of the spadix above the
ambient temperature of the rain forest. A discussion of
infrared heat and its relationship to aroid
pollination follows the chart. Please note the chart
explains the infrared heat rise in Philodendron species
but the basic principal is the same for Anthurium
species.
All living
beings produce infrared heat. It
is suspected by entomologists there are approximately 900
species of Cyclocephala beetles but only about one
half have been scientifically identified.
One of these beetle
species has evolved to be the specific or "assigned" pollinator of
any particular aroid thus helping to keep the species pure. Once the bodies of those "assigned"
pollinators come in contact with the aroid's spadix they collect and hold pollen grains from one
inflorescence which is shedding pollen during male anthesis
and transport it to another bloom which is at female anthesis.
Once transferred to the tiny female flowers which are sticky, the result is
pollination leading to the production of berries and seeds. The beetle
in Marc's photo right is Cyclocephala colasi shown eating pollen on a
Philodendron specimen.
French aroid pollination expert Dr. Marc Gibernau (GHEE-ber-no) of the University Paul Sabatier in Toulouse, France now suspects the beetles are also attracted to the spadix in the darkness of the forest due to the infrared heat produced during sexual anthesis. In both private and public discussions with Marc in Miami, FL in September, 2008 he explained in a presentation to the International Aroid Society as well as to several of those of us individually who are interested in aroid pollination there is a significant increase in temperature above the ambient temperature of the rain forest at night once the inflorescence reaches anthesis. The average Philodendron temperature increase is approximately 12 degrees Celsius (21,6 degrees Fahrenheit) above ambient but a few plant species can increase in temperature by as much as 20 degrees C (36 degrees F). The heat can be so intense it can be felt on the palm of an opened hand held in front of the spadix. On the chart above the spadix shown is Philodendron solimoesense. If you notice the temperature gradients you will see the spadix of Philodendron solimoesense increases in temperature 14 degrees C or close to 25.2 degrees F above the surrounding rain forest ambient temperature.
In photographic documentation seen on this chart and shot with an infrared camera the "glow" of a sexually mature Philodendron solimoesense spadix is "visible" and Marc theorizes the beetles can detect that infrared heat with a method somewhat similar to a pilot seeing the glow of a runway light during the night. Since the beetle uses the spathe and spadix as a source of food (pollen) and a place for warmth during its own sexual reproduction with a mate, the "glow" is an open invitation to fly to that source of food, shelter and warmth. At present, Marc and his associates are working to prove the beetle does not actually "see" the infrared heat but instead detects it with receptors on their antennae or bodies instead of seeing it with their eyes.
Marc forwarded these additional comments in a
personal email received on October 14, 2008:
"My picture (below) is an
inflorescence of Philodendron solimoesense. On day one the
female flowers are receptive and the next day the male flowers
produce pollen because the flower are
synchronized. On the first day the
inflorescence is at the female stage and all stigma are
receptive for fecundation/pollination by pollen grains. On the next
day (2nd day), the stigma are no longer receptive but the anthers
are fully ripe (mature) and shed the pollen. In a few species,
such as
in some Anthurium, these two sexual phases are overlapping and
self-pollination may occur. Hence, aroids need pollen vectors
(insects) for pollination between different inflorescences.
The Cyclocephala beetles carry
the pollen from a male-stage inflorescence to a female-stage inflorescence.
From the standpoint of a botanist the aroid reproductive structure would be the
same as to view
the inflorescence, which is composed of many flowers packed together,
to functionally
"behaves" like a flower."
As a result of the
Cyclocephala beetle bringing pollen from one Anthurium to another
Anthurium or Philodendron to
another Philodendron, the species is able to grow viable seeds.
I asked Marc how the beetles find the inflorescence in the dark of the forest and was told the two attractants (thermogenesis and infrared heat) appear to work together since the pheromone produced by inflorescence can travel on the wind for 200 meters or so the beetles apparently first detect the scent in the wind. Since the wind shifts through the forest they have to fly a zig zag pattern back and forth in to follow it to the source. Once they are close enough to "see" the "glow" of the infrared heat they are drawn to the source in the same way a pilot sees his destination runway and simply follows the "lights" home.
Although much has been covered in
this short article there is far more to learn! I strongly
recommend each of you consider joining the International Aroid
Society in order to learn even more. Through the IAS
discussion forum Aroid l you can ask questions to many of the world's
top Anthurium experts and be assured of a qualified answer.
You'll also receive an annual copy of the IAS journal Aroideana
which is highly respected in the scientific community as well as
four quarterly newsletters. Annual membership is only
$25.00 per year!
Steve Lucas
Curator, The Exotic Rainforest
Steve@ExoticRainforest.com
S
Click the links below for
information:
For even more
information, join the
International Aroid Society:
http://www.exoticrainforest.com/Join%20IAS.html
Want to know more about the pollination of aroids? Read Julius Boos' article here: http://www.exoticrainforest.com/Natural%20and%20artificial%20pollination%20in%20aroids.html
Incredible aroid botanical
photographs by botanist David Scherberich
http://www.aroidpictures.fr/pictures.html
Concerned about calcium oxalate crystals? Have you been convinced they
are a "deadly poison"?
Specimens may be available from
Brian's Botanicals
http://www.briansbotanicals.net/
Natural Selections Exotics www.NSExotics.com
More incredible aroid photographs by botanist David Scherberich
http://www.aroidpictures.fr/pictures.html
And for additional information from competent researchers and growers, join the International Aroid Society: http://www.exoticrainforest.com/Join%20IAS.html
You can click on any photo and be taken directly to the description of
that Anthurium including information on where it is found in nature.
Concerned about calcium oxalate crystals? Have you been convinced they are a "deadly poison"?
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