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Philodendron Selloum

Phillodendron selloum (common name: lacy tree philodendron) is within the Family Araceae. This plant is native to Southern America, namely to Brazil, Bolivia, Argentina, and Paraguay. There are nine other philodendron species which include P. consanguineum, P. cordatum, P. fragrantissimum, P. giganteum, P. hederaceum, P. imbe, P. lingulatum, P. marginatum, and P. speciosum.

Taxonomy
Kingdom	Plantae – Plants
Subkingdom	Tracheobionta – Vascular plants
Superdivision	Spermatophyta – Seed plants
Division	Magnoliophyta – Flowering plants
Class	Liliopsida – Monocotyledons
Subclass	Arecidae
Order	Arales
Family	Araceae – Arum family
Genus	Philodendron Schott – philodendron
Species	Philodendron selloum – philodendron

History

Heinrich Wilhelm Schott (1794-1865) was one of the earliest botanists who studied the Araceae family, but he also did extensive studies of Philodendrons. The names Philodendron bipinnatifidum and Philodendron selloum were accepted as two separate species in the past. However, recent studies focused on the sexual characteristics suggest that they are multiform of the same species. Botanist Simon Mayo documented that these were names of the same plant species that exhibited slight anatomical differences. Since the name Philodendron bipinnatifidum was the first of the two to be published in the literatures, it was accepted as the scientific name. However, many botanists have not forgone the use of P.selloum.

• 
  Philodendron selloum taken at BU greenhouse

Distribution

Although native to Brazil, Philodendron selloum is grown as a landscape plant throughout the tropical areas of the U.S –more specifically, the East coast and Southern Florida.

Description

Growth Habitat:

Philodendron selloum is a tropical plant that is usually grown in full sun, but can tolerate and adapt to deep shades. It grows best in rich, moisture-retentive soil that can be slightly alkaline. However, it cannot tolerate high salt concentration in soil.

It is capable of supporting itself at massive heights by producing tree-like bases. However, it will exhibit epiphytic characteristics if given the opportunity to attach itself to a nearby supporting tree and climb upon it. The trunk of this plant can send down many strong aerial roots that not only give support to the overall plant mass, but also serve to absorb water and nutrients from the soil. This plant is greatly known for its ease in covering a land mass, and typically spread out its tree-like trunk from anywhere between eight to ten feet. Leaves can grow up to 4-5 m tall and wide. This plant also contains a spadix and spathe that are usually white or inflorescent.

Distinguishing features:

The leaves are simple, large, deeply lobed, and are usually drooping. These can grow up to 4-5 m wide, and are attached to long, smooth petioles. They are a deep green color, and since these plants are grown in the tropics, there is no apparent color change that correlates with the fall season. The trunk of P.selloum is relatively thick and woody with characteristic “eye-drop” leaf scars. Approximately 15-20 years is required for P.selloum to grow to an appropriate size and produce flowers in an indoor environment where space is limited. The small, petalless flowers are on a spadix that is enclosed within a spathe.

• 
  leaf of philodendron selloum, BU greenhouse
• 
  eye-drop leaf scars, BU greenhouse

Reproduction

The reproductive organ consists of a spadix grown at the center of a reproductive layer called the spathe. The spathe is sometimes mistaken to be a flower, but it is really a modified leaf that serves to protect the spadix. The spadix is divided into three sections: fertile male flowers at the tip, sterile male flowers at the center, and fertile female flowers toward the end of the flower chamber. The sterile male flowers in the mid-section serve to prevent self-fertilization and to produce heat. Pollination is done by a Cyclocephala beetle species. The sterile male flowers produce and maintain a constant temperature that is 30°C above that of the environment during the two days the entire flower structure is open. Interestingly, P.selloum metabolizes fat, instead of carbohydrate, to fuel this process. This feature indicates a possible evolutionary convergence where this plant species and animal species derived similar mechanisms to utilize fat reserves for energy consumption. The main reason for raising and maintaining the flower’s temperature is for volatilizing and dispersing insect attracting odors. The constant high heat production increases the distance that the scent can be picked up by the beetle, and increases the probability of pollination. Additionally, the heat creates a hospital climate that helps to activate the beetle once it is inside the flower. This will also increase the probability of pollination.

• Inflorescence, copyright Jim Edwards
  Inflorescence, copyright Jim Edwards

Uses

P.selloum is a popular ornamental plant for the indoors and outdoors. It is purposely grown as a landscaping plant in much of Southern Florida.

Toxicology

Species within the genus Philodendron are poisonous to vertebrates, but vary in their toxicity levels. They contain calcium oxalate crystals in raphid bundles, which are poisonous and irritating. P.selloum sap may cause skin irritation. Chewing and/or ingesting parts of the plant may result in severe swelling and compromised respiratory functions.

References

Brown, D. (1988). Aroids: Plants of the Arum Family. Portland, OR: Timber Press, 1988

Boyle, Jennifer; Holstege, Christopher (2008). “Toxicity Plants- Caladium, Dieffenbachia, and Philodendron”. eMedicine WebMD http://emedicine.medscape.com/article/1009003-overview

Gilman, Edward F (1999). “Philodendron selloum”. University of Florida; The Institute of Food and Agricultural Sciences.

Mayo, S. J. (1990).History and Infrageneric Nomenclature of Philodendron (Araceae). Kew Bulletin. Vol. 45, No. 1, pp. 37-71

USDA Natural Resource Conservation Service. “Plants Profile: Philodendron Schott” Accessed 3 May 2009 http://plants.usda.gov/java/profile?symbol=PHILO

Barabé D, Lacroix C, Jeune B (2002). Study of homeosis in the flower of Philodendron (araceae): a qualitative and quantitative approach. PubMed 90(5):579-92

Moodie. G. E. E. (1976). “Heat Production and Pollination in Araceae”. Canadian Journal of Botany. 54: 545-546

Ombrello, T. “A Hot Philodendron.” UCC Biology Department http://faculty.ucc.edu/biology-ombrello/POW/Philodendron.htm

Otterspoor, Sean (1997). “Thermogenicity in the Ariods; Inflorescences hot under the collar” Accessed 3 May 2009 http://www.beardedman.net/science/aroids/