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Aroids and other genera in the Collection      Take the Tour Now?     Orchids

The Exotic Rainforest
Plants in the Exotic Rainforest Collection
The images on this website are copyright protected. Please contact us before any reuse.
In depth information on how to grow Philodendron species, Click this Link

Within our collection we have many species of Philodendron.  If you are seeking other photos, click this link:

      Philodendron sagittifolium Liebm.               
Philodendron tanyphyllum, Philodendron sanguineum,  
lancigerum, Philodendron tuxtlanum,
Philodendron daemonum, Philodendron ghiesbrechtii

This page is the photographic documentation of the development of a spathe and spadix of Philodendron sagittifolium during anthesis (reproduction). 
All photographs were taken in June, 2008.


It is important you read the link just below before reading the information on this page.  If you do not have a basic understanding of the pollination of aroid species you will not be able to adequately comprehend all of the information in this article.  If you have already read this link, please continue.

The leaves of Philodendron sagittifolium can grow quite large and the inflorescences stand erect.  The plant is capable of producing one or more inflorescences per axil.   I have previously described the "axil" as a plant structure but the correct explanation of the term "axil" comes from Dr. Tom Croat,  "The “axil” is not really a plant structure but quite simply the axis of the stem and petiole.  Inflorescences emerge from a bud in the axis of the petiole."

 We have physically observed up to 5 inflorescences at the same time on our specimen.  However, the color and shape of the spathe may be variable and may not match the photos on this page exactly.   A spathe is not a flower, but instead is simply a modified leaf used for reproduction.  The flowers, both male and female, develop on the spadix at the center of the inflorescence.    Reproduction is explained by Julius Boos in the above link.

The peduncle, which is the plant structure that supports the spathe, normally measures 4 to 5cm long (1.5 to 2 inches).  The spathe is somewhat flattened and green, but is often tinged with red on the inside.  The spathe usually measures 8 to 22cm (3.4 to 8.6 inches) in length.  The spathe below is on the larger end of that scale.  But since the spathe can be somewhat variable the interior is sometimes not the color shown.  We have observed the spathe to be narrow at the center but that does not always occur as can be seen in the photo on the main page of this website for this species.  We have observed small spathes that are almost totally tubular.

Cyclocephala beetles feeding on Philodendron pollen, Photo Copyright 2008, Marc Gibernau, FrancePhilodendron sagittifolium can produce an inflorescence almost any time of the year, but normally after the beginning of the dry season and continuing throughout most of the rainy season.  We typically see the spathe and spadix in our artificial rain forest in May and June of each year.  In nature, there is a slight shift based on geography when the  "flowering" begins about one month earlier in Mexico and Guatemala (late winter) but less frequently in September and October.  Inflorescence production continues longer in Panama and is seen in February through September and has rarely been observed in December. Once pollinated, the fruits take approximately two months to mature.  However, in our atrium, we do not have any natural pollinators (beetles) present to service this species so we have never observed the development of fruit. 

Pollination in nature is done by a species of Scarab beetle.  The beetles remain inside the spathe only long enough to pollinate the female flowers, eat some of the pollen, find shelter from the cool rain forest night, and breed.  French researcher Dr. Marc Gibernau from the University Paul Sabatier in Toulouse, France has studied aroid pollination since 1998.  Marc added this explanation, "one reason for the beetles to leave the inflorescence which is a great place to stay is that the spathes close and force the beetles up along the spadix.  Once above the male zone they will eat some of the pollen.  If they don't go up they can finish by crashing the spathe against the spadix,  I observed it once in French Guiana.  So the plants "decide" when the pollinators arrive and depart."  The Cyclocephala beetles in Marc's photo can be seen near the bottom of a Philodendron spadix as they eat the pollen.

Unfurled inflorescence of Philodendron sagittifolium Liebm., Photo Copyright 2008, Steve Lucas,                In both early May and in early June of 2008 we had groups of spathes develop on each of two axils.  The photos here of a single specimen developed on our Philodendron sagittifolium in June and then entered anthesis.  This time I was determined to track that inflorescence photographically and as a result stayed up almost continually for some 36 hours plus.  This is the photographic record of the opening and closing of that spathe over a 2 day period.  Some of the information is simply my personal observations but other material (which is credited )was provided by aroid botanist Dr. Tom Croat of Missouri Botanical Garden who is America's top aroid botanist.   Additional  material was taken from his published journals.  A great deal of the information and explanation was provided by aroid expert Julius Boos with input by Marc Gibernau and Leland Miyano.

A note of explanation:
This event happened largely at night as is common in nature.   Almost all the photos were taken in total darkness without the aid of a tripod with the camera and a telephoto lens held in my hands due to the lack of space to set up a tripod.  The inflorescence was over 2 meters  (7 feet) or more away from the only spot a photo was possible due to our pond being between the camera and the subject.  With only a flashlight to find a focus some of the photos are not tack sharp so please accept my apologies.


Inflorescence of Philodendron sagittifolium newly opened, Photo Copyright 2008 Steve Lucas,                Day one

The spathe of Philodendron sagittifolium was first noticed in the early morning hours and was not fully open.  The event began well before we made the first observation.  There is a second spathe directly behind this one, another to the left, and two above.  All will eventually opened in progression and all are on the same axil a total of 5.  The spathe measures 21cm (8.25 inches).  This photo were taken in the late afternoon on day one of the event. 







Approximately 9:00PM

Philodendron sagittifolium inflorescence, Photo Copyright 2008, Steve Lucas,               There is a slight smell of mint to the pheromone produced by the spadix.  The pheromone is a fragrance used by insect pollinators as a "guide" to find the spathe in the darkness of the rain forest.  If you are unfamiliar with the pollination in aroids READ THIS LINK before continuing.  Otherwise, you will not understand the progress of these photographs.  The red dots were not there this afternoon, but are clearly visible now.  Dr. Croat explains below.

French aroid pollination researcher Marc Gibernau provided these additional comments:  "I found it surprising the resin is produced a few hours after the spathe
opening (you wrote 9 PM) it is supposed to be about 24 hours later. As you
can't have miss the opening of the spathe on the night before, I suspect
that the cycle is a bit accelerated in this species or under cultivation
conditions.  So apparently no pollen is shed by your Philodendron.








Philodendron sagittifoliuminflorescence, Photo Copyright 2008, Steve Lucas,          Aroid botanist Dr. Tom Croat explains the red dots which is a naturally produced resin:  "The resin gets on the beetles and makes them sticky so that when they leave they can carry away the pollen which otherwise won’t stick to their bodies."

Aroid expert Julius Boos added these notes:  "Once more I tout Deni Bown`s fantastic book which we all should own and read!---Aroids, Plants of the Arum Family.  She fully explains the purpose of this resin which is produced on the spadix, and seems unique to the genus Philodendron.  She report on this resin on pg. 215, and goes on lower down on the page to discuss the nectaries which occur on many aroids on the surface of the spathe, or on the peduncles, bases of some species leaves, etc. and, as Dr. Croat explained, act as ant attractants when they produce a sweet liquid.   I have observed this on Urospatha, as in Florida we have a very small red ant which is slow and almost invisible, but which stings like hell, and can really spoil your day.   They used to love this nectar produced by these very special glands on my Urospathas, and I have been stung by them many times when I did not take note of their presence on a bloom!

Thanks for your indulgence.


 Day two


Philodendron sagittifolium spathe and spadix at anthesis, Photo Copyright 2008, Steve Lucas, www.ExoticRainforest.comNo significant change but an added note on pollen production which I had been asked to attempt to observe and photograph.  Normally during the evening the plant in a wild setting would produce copious amounts of pollen which would "string" downward.  The exact timing of that pollen production depends of several factors.  Each evening I did my best to check the photographs for any sign of pollen but never was able to observe any.  Julius Boos provides a possible reason, "Let`s keep in mind that some Philodendrons will not or do not produce pollen in cultivation  The famous Philodendron spiritus sancti being one of those species.   My opinion on a ''why'' is that conditions in the green house are just not right.  At least not to the plants that need to enable it to produce the usually very obvious and copious amounts of pollen seen in other Philodendron which seem to ''like'' their growing conditions.  Recently I saw many Philodendron xanadu blooming in beds at a large commercial property, blooms were at many stages, some fully open (the tops of the spathes, that is).  Others produced pollen like crazy, and still some were closed with only the tip of the spadix visible and the spathe closed tightly around it.   Ron Weeks reported that his plants (possibly in a greenhouse)  bloomed, but never opened ''correctly'' or produced any pollen."

Although we do everything possible in the Exotic Rainforest atrium to provide "rain forest" conditions including high humidity, multiple overhead watering twice daily, and as perfect slightly filtered light as is possible, it appears the plant still knows it is not in its natural conditions.



Philodendron sagittifolium spathe and spadix at anthesis, Photo Copyright 2008, Steve Lucas, www.ExoticRainforest.comThe pheromone is not apparent early in the morning and no heat from thermogenesis can be detected.  For an explanation of thermogenesis and the heat it produces, read the link provided above.














Philodendron sagittifolium spathe and spadix at anthesis, Photo Copyright 2008, Steve Lucas, www.ExoticRainforest.comThe spathe has rotated close to 20 degrees to the left.  Although no female flowers have ever been present in any photograph, they are there!  The explanation as to why we cannot see them is found later on this page.  It is not strongly evident but the pheromone has begun to return as has the heat of thermogenesis   The scent has changed somewhat and the mint smell is no longer apparent.  All that is now noticed is a musky smell.  Both my wife and oldest daughter could easily detect both the heat and the pheromone.  To detect the heat all that was necessary was to hold a flattened palm in front of the spathe without touching any part of the inflorescence.

French aroid pollination researcher and expert Marc Gibernau has stated the spathe and spadix lie at an angle of approximately 45 degrees to the vertical for a purpose.  The angle is more effective for the heat of thermogenesis to be dissipated along with the spadices' pheromones into the air of the rain forest night.   Notice what occurs in the next photograph.






Philodendron sagittifolium spathe and spadix at anthesis, Photo Copyright 2008, Steve Lucas, www.ExoticRainforest.comThe spathe has now rotated to a 45 degree angle on the axil in to increase the effects of thermogenesis.  It also appears to be slightly closing.  I have read in some material the spathe actually closes around the beetles and they do the work of pollination inside the closed tube.  However, Julius offers a better explanation below.  The pheromone is now only slight and no heat from thermogenesis can be felt on the hand.  The scent is of a slight musk combined with a small amount of mint.  Again, no female flowers can be observed but the explanation follows.

From Dr. Tom Croat, "the receptivity of the female flowers is short once the spathe is open.  They are protogynous, of course, like most Araceae but also promptly timed to be receptive only at anthesis on the first night of flowering.  This prevents self pollination."

In botany protogynous relates to a flower in which the stigma is receptive prior to the pollen being shed from the anthers of the same flower.

And from Julius Boos:  The blooming/anthesis cycle of this species lasts 2 days.  The lower portion (the tube) of the spathe never opens in this species, probably in the entire genus.  I do not believe that this spathe could trap the Scarab beetle pollinators even if it wanted to as they are strong animals.   I once collected about a dozen of them from a bloom in the jungle of E. Ecuador, and was unable to ''hold on'' to them for long as they would burrow (painfully, I may add!) between my fingers and out of my tightly closed fist.

You could take notes and observe if the constriction around the spadix opens, then closes and then opens again when the next bloom goes through its cycle, measurements taken at the ''waist'' and visual observations would tell you if this is happening.  Read pg. 59 of Deni`s book.  Her details esplain a lot about this event there.  I do not believe the beetles need to be 'trapped' by this closing, they could and would escape at any time if they wanted to, but why would they??   Warmth, food (they will eat the sterile flowers as a snack) and lots of partners and sex in a secure ''room'' are being provided, so why would they even Philodendron sagittifolium spathe and spadix at anthesis, Photo Copyright 2008, Steve Lucas, www.ExoticRainforest.comwant to leave? Perhaps the closing of the spathe at the constriction may retain the heat in the lower portion of the spathe tube for the beetles.  When the warmth stops at the end of the cycle, and the food is used up, they just crawl out  picking up pollen on their now resin-covered legs and bodies and fly off to the next available ''ready'' bloom.

By the way, I believe that some sting less bees collect this resin and use it in the construction of their combs/cells and in waterproofing of their nests. 
Native Indians in South America collect it from their nests and use it to make their blow guns both air and watertight."




possibly  Philodendron pollen, Philodendron sagittifolium, Photo Copyright Steve Lucas 2008,

This is a totally different spadix photographed more than one week later.  "Pollen" appears to be seen beginning to develop near the apex (top).  Please read our note below regarding the consistency of this "pollen". 

The spathe has been sliced away in the photo (right) to allow exposure of the interior.  As you are Typical Philodendron pollen, Photo Copyright 2008, Leland Miyanoabout to see and read the spathe will soon close around the spadix blocking all view of  the interior.  The photo to the right was taken at approximately 6:30PM on the second day of the event.  Dr. Croat commented, "When the pollen emerges usually there is no doubt.  It comes out like toothpaste from a tube that has been stepped on but in slender threads."  It appears the spathe is just beginning to develop "pollen" but we were never certain it was pollen we were seeing.   The "pollen" appears to be dampened.  In a personal meeting in his office in late June Dr. Croat indicated the "pollen" in my photographs appeared to be old but the photos were taken just after the spathe opened and as the pollen at least "appeared" to be produced.  I have no explanation other than humidity and moisture for the effect seen in the photograph but am not totally convinced I was ever photographing pollen.

If this is "pollen", the consistency on the spadix at right may have been altered as a result of the perpetual high humidity and twice daily overhead misting in our atrium.  Our atrium is often watered twice each day to simulate a natural rain forest.  Normal Philodendron pollen (photo left) is much "fluffier" and not as compacted as is seen in this and other photographs below.  We are attempting to verify if the pollen for this species should normally be this compressed and "thick".  Julius comments, "I don`t see the typical pollen 'threads' which are rope like on other Philodendron sps.  Aside from the watering, which may have washed the pollen threads away or at least diluted or thinned them, I do see what looks like a paste-like substance where pollen should be seen."

Philodendron sagittifolium spathe and spadix at anthesis, Photo Copyright 2008, Steve Lucas,
2:00AM following morning, all within a 48 hour period

By 2:00AM the following morning the event is almost complete. The spathe is again almost closed hiding all the activity going on inside the now almost sealed spathe and spadix.




The photograph of the "pollel" is of a second spadix with the spathe cut away, not the one in  the original photographs seen on this page.  The spathe lamina began to wrap so tightly around the spadix the outer layers had to be cut away to reveal the interior.  The event could not have been observed or photographed without the removal of the shielding spathe lamina which was blocking the event inside the spathe from view. 

So now we know "where" the male flowers were all along, but where were the female flowers?



So where are the female flowers?

This is Julius Boos' excellent explanation of what I could not originally see.   Read this carefully. It explains a great deal of what I was missing! I've added the photo of the spathe cut away so you can examine it as you read.  This second photo has been purposely left enlarged.  The first shows the zone of female flowers which is hidden beneath a portion of the lower spathe.

"Steve`s excellent photo is of a typical bisexual aroid spadix, in this case the species is Philodendron sagittifolium.

Philodendron female flower zone, Photo Copyright 2008, Steve Lucas, www.ExoticRainforest.comThe lower yellowish section is the zone of female flowers, they were hidden within the globular lower portion or chamber tube of the spathe, and would have been seen to be wet and ''sticky'' earlier on when female anthesis was in progress. They will dry and turn brown shortly. It is not really visible, but just above this female zone is a shorter zone of sterile male flowers, they are thought to be the source of the scent production. This shorter zone is the point at which the spathe is constricted and so closely ''embraces'' the spadix. 

Above this is the resin covered and stained male section of flowers extending upwards to the tip of the spadix. In this case the spadix is said to be fertile to the tip, but in some Philodendrons and in some other bisexual aroids there is a sterile area of male flowers near the tip (or apex) also thought to be involved in scent production.  At male anthesis the fertile portion would be seen to be covered in pollen extruded by the male flowers, this pollen under natural conditions in the jungle would adhere to the emerging beetles glued to their shiny surfaces by the resin seen as a reddish stain on this portion of the spadix.

I hope that this is of help in understanding the pollination mechanism of some aroids.
Thanks for sharing with all of us, Steve. Good Growing,"

 Philodendron sagittifolium with spathe cut away, Photo Copyright 2008, Steve Lucas,

Marc Gibernau added, "The sterile zone just above the female zone is constituted of sterile flowers rich in lipids which are normally eaten by the beetles. I don't think that they produce any scent (but I'm not 100% sure).  I would more suspect the male flowers produced the odor.  If you have more inflos coming up you can verify this point by wrapping plastic bags around the 2 zones and smell them after a while, but don't wait too long because during the heating period they will fill with water because of the exaggerated evaporation."




My sincere thanks to Dr. Croat, Julius Boos, Marc Gibernau, and Leland Miyano.  This message came from Dr. Croat after briefly reviewing this page:  "I read your piece on the flowering behavior of Philodendron sagittifolium and can find no fault with it."











If you failed to read the link below much of the information found on this page will be of little value! 
Pollination of aroids as it occurs in nature.

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