Many websites including a few associated with universities and the U.S. government indicate Philodendron cordatum is a synonym for Philodendron scandens subsp. oxycardium.  Scientifically that is inaccurate since neither the published scientific description of either of these plants nor any recognized scientific data base indicates these species are one and the same.   In science a synonym is a species which has been previously published and described to science but was again published using another name.  This "myth" appears to have been advanced in horticultural circles in the past and has persisted as "fact" with plant collectors as well as some authoritative sources.  "Philodendron cordatum Hort." is nothing more than a common name with no scientific significance.

Philodendron scandens (scan-DENS) was published in 1853 and Philodendron oxycardium (oxy-CAR-deum) was published in 1857.  Both are common house plants and each has was sunk into synonymy in 1856 under Philodendron hederaceum (hay-day-RA-see-oom).  Philodendron hederaceum was described and published much earlier in 1829.

The specimen of Philodendron cordatum growing at the Marie Selby Botanical Gardens in Sarasota, FL shown at the top right of this page was grown from seed collected from a private nursery in Brazil during the early 1970's.  The specimen was originally tagged "P. Angra dos Reis" due to the location where it is commonly seen in nature and was set out at the garden in 1978 where it has survived an extreme low temperature of 4.44 C (24 F) in 1983.  The leaf blades of that specimen measure 38 to 61 cm (15 to 24 inches) in length.   Phil Nelson's photo was provided by Harry Luther of the Marie Selby Garden.

The leaves of Philodendron cordatum are a medium green and become deciduous.   A deciduous plant is one that often looses its leaf blades during periods of dryness.  The blades of P. cordatum are glossy on the blade's top known as the adaxial surface as well as subcoriaceous to moderately coriaceous in thickness.  Coriaceous indicates the blades are leathery to the touch while subcoriaceous indicates they are just less than leathery.  The lower or abaxial leaf surface is matte.  The leaf blades may be moderately bi-colorous or two colored.  The blades cordate as well as ovate (slightly oval) to broadly ovate at the apex.  The base of the blade is cordate with an acute lower tip.  The term acute indicates pointed while cordate indicates heart shaped.  The leaf blades may grow as large as 40 to 65 cm (15.75 to 25.5 inches).

Aroids and other plant species have veins sometimes known as nerves on each leaf blade. The venation is distinct in some species but far less so obvious in others.  Each vein type has a specific name for purposes of being specifically described in to science since specific characterizes are important to the determination of any species..  The most prominent veins on Philodendron cordatum are the midrib, basal ribs, and primary lateral leaf veins. The interprimary or secondary veins are less obvious as are the tertiary or minor veins.  There should be 5 to 7 primary lateral veins on each side of the midrib at the center of each leaf. 

The midrib as well as basal ribs of Philodendron cordatum possess nectaries that appear as purple/reddish splotches having the color of reddish wine.  In botany this coloration is known as vinaceous (as in the color of purple grapes) and these nectaries sometimes exude a sweet sugary extra-floral liquid.   Although the purple splotches can be observed on other parts of the plant the color alone does not always indicate a nectary is involved.

Nectar is often produced as a part of pollination but plant structures that produce nectar for reasons other than attracting a pollinating insect are known "extra-floral".  These extra-floral nectaries have been observed in at least 2000 species in as many as 64 plant families and are not uncommon in Araceae.  The nectaries can be found on portions of the plant that are not associated with flowers or reproduction. 

Flowers commonly produce nectar as a reproductive attractant to cause a pollinator to visit.  The accepted theory for non-reproductive nectaries includes assisting the plant to maintain a balance between the water and sugars inside the xylem and possibly as a defensive mechanism.  The xylem is a tissue inside the stem and petiole that conducts water along with sugars and mineral salts from the roots to all parts of the plant.

Extra-floral nectaries often attract ants and the ants in turn appear to protect vulnerable leaves as well as tempting plant parts from animals that graze.   Many plants including Philodendron species are known as myrmecophytes or "ant plants".  A myrmecophyte (myr-MECO-fit) is a plant that lives in association with a colony of ants and possesses specialized organs to entice the ants to build a colony around their stems (base of the plant).  The plant specimen then obtains nutrients from the nest as well as aeration of the soil which allows the roots to grow more freely.  

The aggressive nature of the ants towards any intruder appears to protect the plant from other animals or insects who would eat its parts.   The subject of non-reproductive sugars used as an insect attractant is complex and the relationships between individual plant species and a variety of insects is not well understood.

The posterior or forelobes contain three to six basal ribs per side.  The major veins are flat to only slightly raised and are paler in color on the upper surface.  The same veins are convex (raised) on the lower or abaxial surface.  The minor veins also visible. 

Although commonly called a "stem" the stalks that support the leaves are known as petioles.  The petiole connects the lamina of the leaf blade to the stem at the petiole's base.  Petioles grow from a bud on the stem and transfer water along with nutrients to the leaves via a unique form of hydraulic pressure.  Rather than being pushed upwards the water is drawn to the blade by evaporation into the atmosphere though the upper blade surface.  The leaf blades absorb carbon dioxide in the air and convert it into oxygen for all living organisms to breathe. 

The petioles are marked with purple blotches as is the midrib and other portions of any mature specimen.  The petioles of Philodendron cordatum are weakly flattened as well as slightly spongy to the touch and typically measure between 55 to 61 cm (21.5  to 24 inches) on an adult specimen.  If examined closely a slight striation can be observed (photo, right, below).  Striation is simply lines running along the axis of the petiole.   

The cataphylls of Philodendron cordatum are double keeled (two ribbed) as well as a medium green in color.  A cataphyll protects the newly emerging leaves as they form and are a bract-like modified leaves that surround any new blade as it first emerges from the bud.   A double ribbed cataphyll is known as a prophyll and is a specially modified cataphyll with two ribs or "keels" running along the posterior surface.   The cataphylls of P. cordatum are deciduous and fall from the plant once the blade develops.   The cataphyll/prophyll of a mature specimen measures approximately 29 to 40 cm (11.4 to 15.75) and is narrowly triangular in shape.  As the cataphyll matures it changes from green to yellowish-green before finally turning rusty red.  The cataphyll is also covered with vinaceous extra-floral nectaries. 

The stem of any Philodendron is the base or central axis of the plant and is the plant's main support.  Petioles, buds, cataphylls, roots and the peduncles which support the inflorescences of the specimen grow from the stem.  The stem collects and stores water collected by the roots which grow from the nodes at regular intervals along the stem's length.  The stem segments which separate the nodes are known as the internodes.    Depending on the age of the specimen the internodes are typically 6 to 8 cm (2.3 to 3 inches) long but may be shorter in young plants.  The internodes and are light brown in color. The stem of P. cordatum is green becoming grayish as the plant matures. 

Philodendron species are members of the larger plant family Araceae (uh-RAY-see ee) commonly known as aroids.  An aroid is a plant that reproduces via the production of an inflorescence known as a spathe and spadix. Although many growers believe the spathe is a "flower" the spathe is simply a specially modified leaf whose purpose is to protect the spadix at its center. 

The spathe does not qualify as a flower since it possesses no sexual parts.  All flowers have pistils, stigmas ,ovaries, ovules, stamens and anthers.  Without those sexual parts a flower has no way to be fertilized or reproduce.  A spathe possesses none of these parts but all can be observed on the spadix at its center.  The spadix appears as a spike on a thickened fleshy axis which does in fact produce tiny flowers. 

When ready to reproduce the spadix of a Philodendron produces male, female and sterile flowers which are cleverly divided by Mother nature into separated zones in order to prevent self pollination.  The female flowers are hidden inside a region at the bottom of the spathe known as the "floral chamber" with the sterile male flowers secreted just above.  The fertile male flowers which produce pollen are in another region which is exposed on the visible portion of the spadix well above the floral chamber.  The purpose of the sterile flowers is to produce a perfume-like substance known as a pheromone which attracts the appropriate pollinating insects but it also serves as a source of protein for the visiting insect pollinators by producing lipids.

The sterile male flowers begin to entice pollinators which are normally small beetles from the genus Cyclocephala by sending out their pheromones on the breeze which floats through the forest.  Those beetles gather pollen from another member of the same Philodendron genus and bring it to the female flowers while being enticed to fly to the source of warmth and food in the coolness of the rain forest evening.  The beetles can "see" the inflorescence since it produces both a scent and a "glow" in the form of infrared heat which is suspected to be visible to a special receptor on the end of their antennae. 

Philodendron species produce their female flowers on the first evening of anthesis and they are no longer receptive by the time the male flowers begin to produce pollen on the second (possibly the third) evening.  This is another of nature's ingenious ways to keep her species pure.  If the female flowers are pollinated with pollen of another plant of the same species which is already at male anthesis and are carried by an appropriate beetle from the second specimen they may in time produce berries containing seeds.   No photo of the inflorescence or a scientific record of the color of the berries produced by Philodendron cordatum can be located.

If you are interested in a more detailed account of how aroids reproduce please visit this link:  Natural and artificial pollination in aroids.

Philodendron cordatum produces one to three inflorescences per floral sympodium (axil).  The inflorescences are supported by a stalk known as a peduncle which can measure 3 to 9 cm (1.2 to 3.55 inches) in length.  The spathes typically measure 17 to 21 cm (6.7 to 8.25 inches) long and are slightly constricted at the center.  The outer portion of the spathe blade is green to a greenish cream color and also exhibits vinaceous grooves once immature.  The spathe becomes cream colored on both the inner and outer surfaces once the inflorescence approaches anthesis finally turning pinkish red to red on the outer surface once anthesis is complete.   The spadices typically measure 15 to18 cm in length. 

Philodendron species are known to be highly variable and not every leaf of every specimen will always appear the same.  As can be seen in the photos on this page, Philodendron species go through morphogenesis (ontogeny) as they mature.  This link explains in non-technical language natural variation and morphogenesis within aroid and other species.   Click here.

My thanks to Leland Miyano for his expert input as well as John Criswick and Phil Nelson for the use of their photos.  Phil Nelson is associated with the Marie Selby Botanical Gardens in Sarasota, FL.
 

The scientific data for this article was extracted from the published field notes of Dr. Thomas B. Croat Ph.D., P.A. Schulze Curator of Botany at the Missouri Botanical Garden in St. Louis, MO.  as well as from the Royal Botanic Kew's CATE Araceae.  You can view the scientific information for Philodendron cordatum Kunth on TROPICOS (a service of the Missouri Botanical Garden) including enlargeable photos here:  http://www.tropicos.org/Name/2103189

Cate Araceae can be found here:
 http://www.cate-araceae.org/index.do;jsessionid=96982249A0181F1EB1E74E6CEB9841D4

Philodendron cordatum does not match the scientific description of either Philodendron scandens, Philodendron oxycardium nor the accepted species name Philodendron hederaceum.  You can read our synopsis for Philodendron hederaceum (Philodendron scandens, Philodendron oxycardium) here.

Looking for a specimen? Contact

http:///



http://www.briansbotanicals.net/index2.html

or