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Anthurium regale Linden
 Growth of an inflorescence   
Please note:  This page contains numerous photographic images. 
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                       Photos 2006/2007 Steve Lucas

Anthurium regale Linden
Growth of an inflorescence

To read our observations regarding this species click on this link:
Anthurium regale.
This is Page 2:  Day 1 through Day 16 of the growth of the spathe and spadix
To advance to Day 17 to 31 Click Here
Definitions of botanical terms you will encounter:
Anther - (AN-ther)
The part of the stamen where the pollen is produced and contained
Anthesis - (an-THE-sis) 
The period during which a flower is fully open and functional.  The time of pollination or bloom.
Inflorescence - (in-flor-ES-ence)
A group or cluster of flowers on a branch of a plant, in botany used to describe the structure of a spathe and spadix

Infructescence - (in-fruc-TES-sence)
The fruiting stage of an inflorescence

Nectar - (NEC-tar)
The exudate produced by the spadix in to attract pollinators

Perigone - (PERU-gown)
Collective term for the outer parts of a flower (parts of the spadix in this case) enclosing the stamens and pistils

Pheromones (fer-UH-mones)
A scent produced by the spadix during anthesis to attract insect pollinators and distribute pollen.

Pistil - (PIS-til)

The female, ovule-bearing organ of a flower, including the stigma, style, and ovary
Pollen - (POL-in)
sometimes incorrectly called flower sperm, is a fine to coarse powder consisting of pollen grains which produce the male
gametes (sperm cells) of seed plants
Stamen - (STA-men)
 Male reproductive parts of a flower

Stigma - (STIG-ma)
The pollen receptive surface, usually sticky, where the pollen enters the pistil. Usually the stigma will bear a sweet
solution which can attract insects to the sticky surface of the stigma where pollen is received and on which pollen

Stigmatic Hairs (stig-MAT-ic)
Hairs at the end of the stigmas designed to entrap the pollen grains.  These trichomes may also induce germination of the pollen grains.

The photos on this page are the documentation of the development of our first inflorescence (spathe and spadix)
our specimen of Anthurium regale.  The specimen was acquired in September, 2005.  It had no leaves and was
small when it arrived.  Unlike descriptions I've sometimes read on the internet which claim A. regale is a slow
grower, during the first 14 months of growth the plant grew rapidly and produced 5 leaves, one of which was
accidentally destroyed.  In mid December 2006 I began to notice what I thought was the development of a 6th new
leaf.  Since the production of a spathe is apparently not common for this species in cultivation I was not expecting an
inflorescence.  However, I did note the new growth was not forming as previous leaves had formed.  Instead it
formed directly alongside the last large petiole which had grown just 6 weeks before.  That last leaf measures
73cm (29 inches) and the petiole is 90cm (3 feet) long.  I was excited about the prospect of the next leaf since
each leaf has been larger than the last.   I was even more excited to see the new "leaf" was not a leaf, but instead
a spathe and spadix. 
The entire spathe and peduncle measured 38cm (15 inches) from the base to the top of the
This is simply a personal observation, but it is my believe the plant grew quickly and has produced this
inflorescence within the first 14 months of growth due to the conditions in our atrium.  We maintain filtered light
with a humidity level of 85% + at all times.  The temperatures are moderate most of the year.   As a result, our
conditions closely match the natural growing conditions the plant experiences in Peru.

The spathe was first discovered on December 19, 2006.  The Day 1 photograph depicts the spathe as it was first
seen on that day.  Although difficult to see in the first photograph the spadix is just beginning to be seen near the  
top of the spathe.  The spathe measures 20cm (8 inches).  In the second photo you can just begin to see the spadix
at the top 5cm (2 inches) of the inflorescence on day 2.  The spathe has begun to open
slightly more.
I'm told by two experienced growers the female stamens are now beginning to approach their anthesis and will soon
be receptive.  However, since I do not have a source of pollen, there is no way to pollinate the spadix, thus producing seeds.  I'm frantically doing research.  One knowledgeable grower has suggested it may be possible to remove the
entire spadix to refrigerate it for pollination of the next inflorescence.   Julius Boos has recommended letting it play out
and attempting to collect pollen with a camel hair brush.   At this point, I've elected to simply track the growth, attempt to collect pollen, and record it photographically.   I've located another semi-large plant and will be adding it to the collection very soon in to increase the odds of having pollen the next time this occurs.
This information came from Dr. Tom Croat of the Missouri Botanical Garden on December 20, 2006:
"It will be difficult to get pollination from one spadix because typically the plants are very protogynous and pistillate flowers
are no longer functional when the pollen is fresh."
 "Protogynous" indicates the plant functions first as a female producing receptive flowers, then as a male producing pollen. 
In an effort to learn more about this process I ran across an article by Neil Carrol.  Neil states, "Anthuriums have perfect flowers, bearing both male and female working parts. The difficulty is this; the stigma (female) is ready for pollination before the  pistals (male) presents its pollen. In nature this helps to insure cross-pollination and discourages self-pollination."  He
"Telling when a particular Anthurium inflorescence is ready for pollination is a very easy matter.  The stigma will exude a drop of fluid which will sit at the apex of each individual flower on the spadix. Some species present this droplet on all flowers at the
same time and others may present theirs in succession. This usually takes place in the early morning hours.  At any rate when
these droplets are present, the flower is 'ready' to be pollinated. 
Dr. Croat later offered this advice on the afternoon of December  20, "If your spathe is completely unfurled  and the spadix exposed it could reach female anthesis soon.  It could be days or weeks though depending on the species.  Essentially you need pollen as soon as you have glistening stigmas or droplets forming on the pistils."
Obviously the spathe is not completely unfurled at this point (day 2, second photo).  I am watching the spadix as
closely as my glaucoma ridden eyes will allow for any sign of female anthesis.
Day 3: only a slightly noticeable difference can be observed.  More of the spadix is beginning to become exposed
near the top.  Approximately 4cm (1 5/8th inches) is now exposed.

On day 3, approximately 4 cm of Anthurium regale's spadix is now exposed.Since I've done all I can to duplicate the plant's natural conditions (read the main article) my goal is to be able to eventually pollinate Anthurium regale and produce seeds.  At this point I have elected to simply observe and
photograph this event.  I have located another plant which will be in the atrium in about 10 days (early January  2007).  That could easily take one year to produce a 2nd spathe.  If there are growers out there who have an
Anthurium regale
about to bloom or if you have pollen stored for this species I'd love to hear from you.

Day 4: approximately 6cm (2 3/8ths inches) of spadix is exposed.  No evidence of anthesis can yet be seen.

Anthurium regale spathe Day 5Anthurium regale spadix day 5 closeup
Day 5:  9cm (3.5 inches) of the spadix is exposed.
Anthurium regale spathe day 6
Anthurium regale spadix Day 6
Day 6:  Approximately 8.5cm (3 3/8th inch) of the spadix is exposed.
Anthurium regale spathe Day 7Anthurium regale spadix Day 7
Day 7:  11cm (4 3/8th inch) of the spadix is now exposed.  The spadix in the first photo is near life size.
Anthurium regale spathe day 8
Day 8:  Approximately 12cm (4 3/4 inch) of the spadix is exposed. 
The spadix has not yet reached female anthesis.  But for those of you observing this event and learning about it
along with me this narration was provided by Julius Boos.  Julius is not a botanist, but he should have been!
Julius wrote: "Your bloom still looks to me to be very immature, lots of development still to go!"  He then continues
to explain what we are all seeing happen, "imagine a hen's egg with a small 'nipple' at the top.   (Look at the
close-up of Day 7, you can see the "nipple") "These structures are the female parts, and are respectively the egg-shaped gynoceum (which contains the ovules) and with the stigma at the very top center, which will be larger and more
visible/protruding, and with a tiny drop of liquid at its tip when at the peak of female anthesis.  The pollen adheres to the
liquid on the stigma, and grows down a path to fertilize the ovules.   This anthesis seemingly has not occurred as yet in
your plant, as your stigmas at this stage and in your photos are visible only as a tiny raised point/dot at the very center
of each segment." 
"Now imagine 4 specially flattened, long, narrow, blade-like structures attached at their very bottom to the 'base' of the
'egg', they extend up and around/along its sides, sort of embracing the 'egg', curving over and partially covering the top
of the egg, but leaving its center and stigma exposed.  These structures are collectively known as the perigone.  
They show on your photo as the little 'squares' or 'scollops' around each individual 'egg' and stigma, but because your
flowers are still developing, you are having difficulty seeing where the edges of the perigone segments end and at their
edges overlap on top of the 'egg'."
Part of my goal in photographing this process on a daily basis is to learn what is actually happening as an aroid is
attempting to reproduce itself.  Hopefully, all of us can learn something from the exercise.
Day 9:  Approximately 13cm (5 1/8 inch) of the spadix is exposed.   Still no visible evidence of female anthesis.
The spadix in the first photo is near life size.
Anthurium regale spathe and spadix Day 10
Day 10:  Approximately 13.5cm (5 1/4 inch) of spadix is exposed.   The first photo is near life size.
On Day 11 the spathe appears to be fully open and all 20cm (8 inches) of the spadix is exposed.   Julius Boos sent
an email this morning with more insight.  Julius said, "the spathe will probably reflex (turn away from pointing forward
and face backward on itself) when the spadix goes into anthesis, or immediately before, leaving the spadix standing
completely exposed.
Anthurium regale spathe and spadix Day 12
Day 12:  Exactly as predicted, the spathe has reflexed away from the spadix leaving it fully exposed.   Anthesis should
be imminent.  The spathe itself measures 20cm (8 inches).
Anthurium regale spathe and spadix day 13

Day 13:  Both day 12 and day 13 the weather has been extremely overcast making quality photography difficult. 
Anthurium regale spathe and spadix Day 14
Day 14:  January 1, 2007.
Anthurium regale Day 15 spathe and spadix
Day 15: 
 I will begin to focus the camera on the lower portion of the spadix beginning on Day 16.

Day 16:  Although the "nipples" of the florets appear somewhat enlarged no evidence can be seen of an exudate. 
However, there are more experienced eyes in the world of botany!  Today Dr. Croat wrote:
"I can clearly see the pistils exposed on the lowermost flowers so it is possibly capable of being pollinated but usually there is a more evident sign that it is receptive. Frequently the stigmas form a clear droplet of a sugary solution.  These may swell until the drip off the spadix if no pollinator is removing the solution.  For some species no accumulation is ever evident and itstead the stigmas become glistening, which also signifies receptivity.  This condition is harder to detect but if you are watching this daily you should have no problem recognizing receptivity.  Another sure sign of receptivity is scent so smell the spadix each day.  Many Anthurium have very distinct scents, attracting specific pollinators and the scents are wildly variable, ranging from perfume-like to yeast-like or scents of spoiling fruits. I once had a student studying the quality of the nectar and this is also variable in terms of quantity of nectar produced and the content of the nectar, percentage of sucrose, dextrose, fructose, glucose, etc. Despite having 1000 to 1500 species we know next to nothing about the pollination systems of Anthurium.
It would be a great area of study for a very patient observer."
Photos are continued on the following page.
There are now so many photographs we are forced to divide this discussion into a total of three pages
in to tell the story while allowing those with a dial-up connection to the photographs. 
You are currently on Page 2
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