Philodendron

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Philodendron
Philodendron giganteum, one of the largest Philodendron species
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Alismatales
Family: Araceae
Subfamily: Aroideae
Tribe: Philodendreae
Genus: Philodendron
Schott[1]
Synonyms[1]
  • Arosma Raf.
  • Baursea (Rchb.) Hoffmanns. ex Kuntze
  • Calostigma Schott 1832, not validly published
  • Elopium Schott
  • Meconostigma Schott
  • Sphincterostigma Schott
  • Telipodus Raf.

Philodendron is a large

Greek
words philo- 'love, affection' and dendron 'tree'. The generic name, Philodendron, is often used as the English name.

Description

Growth habit

Compared to other genera of the family

extrafloral nectaries, glands that secrete nectar to attract the ants. The philodendron, in turn, obtains nutrients from the surrounding ant nest, and the aggressive nature of the ants serves to protect the plant from other insects which would eat it.[7]

Secondary hemiepiphytes start life on the ground or on part of a tree trunk very close to the ground, where the seeds sprout. These philodendrons have their roots in the ground early in their lives. They then begin climbing up a tree and eventually may become completely epiphytic, doing away with their subterranean roots. Secondary hemiepiphytes do not always start their lives close to a tree. For these philodendrons, the plant will grow with long

internodes and naked internodes of uncommon length (up to a yard (meter) or more) followed by another clump and so on.[8] Philodendron linnae
is another such species.

A few species show three peaks in temperature during flowering, which stimulates beetles within the spathe and increasing the likelihood they will be sufficiently coated with pollen. A sticky resin is also produced in drops attached to the spadix which help to keep the pollen attached to the beetles.

infrared radiation
.

Leaves

A leaf of Philodendron maximum

The leaves are usually large and imposing, often lobed or deeply cut, and may be more or less

pinnate. They can also be oval (Philodendron 'White Princess'), spear-shaped, divided (Philodendron tripartitum) or in many other possible shape variations. The leaves are borne alternately on the stem. A quality of philodendrons is that they do not have a single type of leaf on the same plant. Instead, they have juvenile leaves and adult leaves, which can be drastically different from one another. The leaves of seedling philodendrons are usually heart-shaped early in the life of the plant. But after it has matured past the seedling stage, the leaves will acquire the typical juvenile leaf's shape and size. Later in the philodendron's life, it starts producing adult leaves, a process called metamorphosis.[11] Most philodendrons go through metamorphosis gradually; there is no immediately distinct difference between juvenile and adult leaves.[12]
Aside from being typically much bigger than the juvenile leaves, the shape of adult leaves can be significantly different. In fact, considerable taxonomic difficulty has occurred in the past due to these differences, causing juvenile and adult plants to mistakenly be classified as different species.

The trigger for the transformation to adult leaves can vary considerably. One possible trigger is the height of the plant. Secondary hemiepiphytes start off on the dark forest floor and climb their way up a tree, displaying their juvenile type leaves along the way. Once they reach a sufficient height, they begin developing adult type leaves. The smaller juvenile leaves are used for the darker forest floor where light is in scarce supply, but once they reach a sufficient height in the canopy the light is bright enough that the bigger adult leaves can serve a useful purpose. Another possible trigger occurs in primary hemiepiphytes. These philodendrons typically send their aerial roots downward. Once their roots have reached the ground below, the plant will begin taking up nutrients from the soil, of which it had been previously deprived.[13] As a result, the plant will quickly morph into its adult leaves and gain in size dramatically. Another quality of philodendrons leaves is they are often quite different in shape and size even between two plants of the same species. As a result of all these different possible leaf shapes, it is often difficult to differentiate natural variations from morphogenesis.

Cataphylls

Philodendrons also produce

internodes
of the plant. The cataphylls will remain attached, drying out and becoming nothing more than fibers attached at the nodes. In some philodendrons, the cataphylls build up over time and eventually form a wet mass at the nodes. This may keep emerging roots moist and provide some form of lubrication to new leaves.

Roots

Philodendrons have both

heliotropic behaviors. Characteristic of roots in philodendrons is the presence of a sclerotic hypodermis, which are cylindrical tubes inside the epidermis that can be one to five cells long.[15]
The cells that line the sclerotic hypodermis are elongated and tend to be hardened. Underneath the epidermis is a unique layer of cells in a pattern of long cells followed by short cells.

Extrafloral nectaries

Some philodendrons have extrafloral nectaries (nectar-producing glands found outside of the flowers). The nectar attracts ants, with which the plant enjoys a protective symbiotic relationship.

spathes. The nectaries produce a sweet, sticky substance the ants like to eat and which provides an incentive for them to build their nests amongst the roots of the given philodendron. In some cases, the amount of nectar
produced can be quite extensive, resulting in the surface becoming entirely covered with it.

Reproduction

Sexual

Inflorescence from Philodendron martianum

When philodendrons are ready to reproduce, they will produce an

inflorescences can be produced at a single time on short peduncles. The spathe tends to be waxy and is usually bicolored. In some philodendrons, the color of the base of the spathe contrasts in color with the upper part, and in others, the inner and outer surfaces of the spathe differ in coloration. The paler color tends to be either white or green, and the darker usually red or crimson. Pelargonidin is the predominant pigment causing the red coloration in the spathes. The upper portion of the spathe is called the limb or blade, while the lower portion is called the convolute tube or chamber due to its tubular structure at the base. The spadix is more often than not white and shorter than the spathe. On the spadix are found fertile female, fertile male, and sterile male flowers. The fertile male and female flowers are separated on the spadix by a sterile zone or staminodal region composed of sterile male flowers. This barrier of sterile male flowers ensures fertile male flowers do not fertilize the female flowers. The arrangement tends to be vertical, with fertile male flowers at the top of the spadix followed by sterile male flowers, and fertile female flowers very close to the bottom in the region known as the spathe tube or chamber.[18] In some philodendrons, an additional region of sterile male flowers is found at the very top of the spadix. The fertile female flowers are often not receptive to fertilization when the fertile males are producing pollen, which again prevents self-pollination
. The pollen itself is thread-like and appears to project out from the region where the fertile male flowers are located.

pheromones to attract the male beetles, usually at dusk. This process, female anthesis
, is followed by male anthesis, in which the pollen is produced. Female anthesis typically lasts up to two days and includes the gradual opening of the spathe to allow the beetles to enter. Some evidence suggests the timing of opening of the spathe is dependent on light levels, where cloudy, darker days result in the spathe opening up earlier than on clear days. During female anthesis, the spadix will project forward at roughly 45° relative to the spathe.

Once female anthesis is nearing its end and the female flowers have been pollinated, the spathe will be fully open and male anthesis begins. In the beginning of male anthesis, the fertile male flowers complete the process of producing the pollen and the female flowers become unreceptive to further pollination. Additionally, the spadix moves from its 45° position and presses up flush to the spathe. Towards the end of male anthesis, the spathe begins to close from the bottom, working its way up and forcing the beetles to move up and across the upper region of the spathe, where the fertile male flowers are located. In doing so, the philodendron controls when the beetles come and when they leave and forces them to rub against the top of the spadix where the pollen is located as they exit, thus ensuring they are well-coated with pollen. One would expect the beetles to stay indefinitely if they could due to the very favorable conditions the inflorescence provides. After male anthesis, the males will go off and find another philodendron undergoing female anthesis, so will pollinate the female flowers with the pollen it had collected from its previous night of mating.

Fruit

Botanically, the fruit produced is a

spathe
will enlarge to hold the maturing berries. Once the fruit are mature, the spathe will begin to open again, but this time it will break off at the base and fall to the forest floor. Additionally, the berries are edible, although they contain calcium oxalate crystals, and have a taste akin to bananas. Many botanical sources will indicate that the berries are poisonous, probably due to the oxalate crystals. Many tropical plants contain oxalates in varying amounts. Sometimes proper preparation can render these harmless, and in many cases eating minor amounts causes most people no distress or minor gastric irritation. However, care should be taken to verify the toxicity of any particular species before ingesting these berries, particularly regularly or in large amounts.

The color of the berries can vary depending on the species, but most produce a white berry with slight tones of green. Some produce orange berries and others yellow berries, though. Still others will produce berries that start off white, but then change to another color with time. Philodendrons that produce orange berries tend to be members of the section Calostigma. Contained within the berries are the seeds which are extremely small compared to other members of the family Araceae. The berries often give off odors to attract animals to eat and disperse them. For example,

monkeys.[21][22]
Insects also may be responsible for dispersing seeds, as beetles and wasps have been seen feeding on philodendron berries.

Eurytomid wasps also seek out philodendrons and are known to lay their eggs in the ovaries of many Philodendron species, resulting in galled inflorescences.[23]

Hybridization

Philodendrons exhibit extremely few physical reproductive barriers to prevent hybridization, but very few natural hybrids are found in nature. This may be because philodendrons have many geographic and time barriers to prevent any such cross pollination.[citation needed] For example, it is rare for more than one philodendron species to be flowering at the same time or to be pollinated by the same species of beetles. The beetles have also been observed to be selective to the height of the plant they pollinate, which would serve as an additional preventive measure to make hybrids less likely. Because of these outside barriers, philodendrons may not have had to evolve physical mechanisms to prevent cross-pollination.[citation needed] Hybrids in nature are only rarely reported. When found, these hybrids often can show remarkable genetic relationships. Crosses between two philodendrons in different sections can occur successfully.

Taxonomy

History

Philodendrons are known to have been collected from the wild as early as 1644 by

aroids were considered to belong to this same genus. The genus Philodendron had not yet been created. Throughout the late 17th, 18th century, and early 19th centuries, many plants were removed from the genus Arum and placed into newly created genera in an attempt to improve the classification. Heinrich Wilhelm Schott addressed the problem of providing improved taxonomy and created the genus Philodendron and described it in 1829.[25] The genus was first spelled as 'Philodendrum', but in 1832, Schott published a system for classifying plants in the family Araceae titled Meletemata Botanica in which he provided a method of classifying philodendrons based on flowering characteristics. In 1856, Schott published a revision of his previous work titled Synopsis aroidearum, and then published his final work Prodromus Systematis Aroidearum in 1860, in which he provided even more details about the classification of Philodendron and described 135 species.[26][27][28][29]

Modern classification

adventitious
roots

Philodendron are usually extremely distinctive and not usually confused with other genera, although a few exceptions in the genera Anthurium and Homalomena resemble Philodendron.[30]

The genus Philodendron has been subdivided into three subgenera: Meconostigma, Pteromischum, and Philodendron.[31] In 2018, it was proposed that Philodendron subg. Meconostigma be recognized as a separate genus, Thaumatophyllum.[32]

The genus Philodendron can also be subdivided into several sections and subsections. Section

Baursia, section Philopsammos, section Philodendron (subsections Achyropodium, Canniphyllium, Macrolonchium, Philodendron, Platypodium, Psoropodium and Solenosterigma), section Calostigma (subsections Bulaoana, Eucardium, Glossophyllum, Macrobelium and Oligocarpidium), section Tritomophyllum, section Schizophyllum, section Polytomium, section Macrogynium and section Camptogynium.[33]

Typically, the inflorescence is of great importance in determining the species of a given philodendron, since it tends to be less variable than the leaves. The genus Philodendron could be classified further by means of differentiating them based on the pattern of thermogenesis observed, although this is not currently used.[34]

Selected species

Main article: List of Philodendron species

Evolution

Philodendron diverged from Adelonema and diversified during the late Oligocene, c. 25 million years ago, in the New World.[35]

Distribution and habitat

Philodendron species can be found in many diverse habitats in the tropical

ecosystems in which they are found. They are found in great numbers in road clearings.[citation needed
]

Philodendrons can also be found in

indigenous and were introduced or accidentally escaped.[39]

Ecology

The leaves of philodendrons are also known to be eaten by

Venezuelan red howler monkeys, making up 3.1% of all the leaves they eat.[40]

The resins produced during the flowering of

Trigona bees in the construction of their nests.[41][42]

The spathe provides a safe breeding area for beetles. As such, male beetles are often followed there by female beetles. The philodendrons benefit from this

lipids
.

Typically, five to 12 beetles will be within the spathe throughout the night. Rarely, cases of 200 beetles at a time have been observed and almost always the beetles are of the same species.

thermogenesis.[45] By the time the spathe is open and the beetles have arrived, the spadix is usually quite hot; up to around 46 °C in some species, but usually around 35 °C. The thermogenesis coincides with the arrival of the beetles and appears to increase their presence. The maximum temperature reached by the spadix remains about 20 °C higher than the outside ambient temperature.[10] The time dependence of the temperature can vary from species to species. In some species, the temperature of the spadix will peak on the arrival of the beetles, then decrease, and finally increase reaching a maximum once again when the philodendron is ready for the beetles to leave. Other species, though, only show a maximum temperature on the arrival of the beetles, which remains roughly constant for about a day, and then steadily decreases.[46]

As the beetles home in on the inflorescence, they first move in a zig-zag pattern until they get reasonably close, when they switch to a straight-line path. The beetles may use scent to find the inflorescence when they are far away, but once within range, they find it by means of the infrared radiation, accounting for the two types of paths the beetles follow.

Cultivation

Growing

Philodendrons can be grown outdoors in mild climates in shady spots. They thrive in moist soils with high organic matter. In milder climates, they can be grown in pots of soil or in the case of Philodendron oxycardium in containers of water. Indoor plants thrive at temperatures between 15 and 18 °C and can survive at lower light levels than other house plants.[47] Although philodendrons can survive in dark places, they much prefer bright lights. Wiping the leaves off with water will remove any dust and insects. Plants in pots with good root systems will benefit from a weak fertilizer solution every other week.[48]

Propagation

New plants can be grown by taking stem cuttings with at least two joints. Cuttings then can be rooted in pots of sand and

peat moss
mixtures. These pots are placed in greenhouses with bottom heat of 21–24 °C. During the rooting, cuttings should be kept out of direct sunlight. Once rooted, the plants can be transplanted to larger pots or directly outside in milder climates. Stem cuttings, particularly from trailing varieties, can be rooted in water. In four to five weeks, the plant should develop roots and can be transferred to pots. Philodendrons can also propagate through air layering which is a more advanced method of propagation that involves creating a new plant on the stem of an existing plant.

Hybridizing philodendrons is quite easy if flowering plants are available, because they have very few barriers to prevent hybridization.[citation needed] However, some aspects of making crosses can make philodendron hybridization more difficult. Philodendrons often flower at different times and the time when the spathe opens up varies from plant to plant. The pollen and the inflorescence both have short lives, which means a large collection of philodendrons is necessary if crossbreeding is to be done successfully.[citation needed] The pollen life can be extended to a few weeks by storing it in film canisters in a refrigerator. Artificial pollination is usually achieved by first mixing the pollen with water. A window is then cut into the spathe and the water-pollen mixture is rubbed on the fertile female flowers. The entire spathe is then covered in a plastic bag so the water–pollen mixture does not dry out; the bag is removed a few days later. If the inflorescence has not been fertilized, it will fall off, usually within a few weeks.

Toxicity

Philodendrons can contain as much as 0.7% of

raphides. The risk of death, if even possible, is extremely low if ingested by an average adult, although its consumption is generally considered unhealthy. In general, the calcium oxalate crystals have a very mild effect on humans, and large quantities have to be consumed for symptoms to even appear. Possible symptoms include increased salivation, a sensation of burning of the mouth, swelling of the tongue, stomatitis, dysphagia, an inability to speak, and edema. Cases of mild dermatitis due to contact with the leaves have also been reported, with symptoms including vesiculation and erythema. The chemical derivatives of alkenyl resorcinol are believed to be responsible for the dermatitis in some people.[49] Contact with philodendron oils or fluids with the eyes have also been known to result in conjunctivitis. Fatal poisonings are extremely rare; one case of an infant eating small quantities of a philodendron resulting in hospitalization and death has been reported.[50] This one case study, however, was found to be inconsistent with the findings from a second study.[51]
In this study, 127 cases of children ingesting philodendrons were studied, and they found only one child showed symptoms; a 10-month-old had minor upper lip swelling when he chewed on a philodendron leaf. The study also found the symptoms could subside without treatment and that previously reported cases of severe complications were exaggerated.

In a 1961 study,

epidemiological studies (which did not necessarily invoke a purée-and-water feeding method) were suggested to be wrong based on the premise that many of the sick cats in those studies may have had pre-existing conditions and merely consumed philodendrons in an attempt to alleviate their illnesses.[53][further explanation needed
]

Some philodendrons are known to be toxic to

intraperitoneally using 3 g of plant extract
from either the leaves or stems. Six rats were injected with the leaf extract and five of them died. Eight rats were injected with the stem extract and two of them died.

Uses

Indigenous people from South America use the resin from bees' nests (made from the species) to make their blowguns air- and watertight.

Though they contain calcium oxalate crystals, the berries of some species are eaten by the locals. For example, the sweet white berries of Thaumatophyllum bipinnatifidum are known to be used. Additionally, the aerial roots are also used for rope in this particular species.

Also, in the making of a particular recipe for

Taiwanos, the leaves and stems of an unknown philodendron species are used. The leaves and stems are mixed with the bark of Vochysia ferruginea and with some parts of a species in the genus Strychnos
.

Yet another use of philodendrons is for catching

coumarins formed during the fermentation process.[55]

Some philodendrons are also used for ceremonial purposes.

spathe to stain their hands red, since many such tribes view the color red as a sign of power.[citation needed
]

Notes

  1. ^ a b "Philodendron Schott". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2023-07-18.
  2. ^ "Philodendron". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2024-06-06.
  3. ^ Mayo 1990, p. 37
  4. ^ Croat 1997, p. 312
  5. ^ Croat 1985, p. 252
  6. ^ Yu 1994, pp. 222–223
  7. ^ Gibernau et al. 2008, p. 689
  8. ISBN 978-1-60469-201-3
    .
  9. ^ Barabé, Gibernau & Forest 2002, p. 81
  10. ^ a b Nagy, Odell & Seymour 1972, p. 1195
  11. ^ Ray 1990, pp. 1599–1609
  12. ^ Bell & Bryan 2008, p. 26
  13. ^ Orihuela & Waechter 2010, pp. 119–122
  14. ^ Croat 1985, pp. 253–254
  15. ^ French 1987, pp. 891–903
  16. ^ Blüthgen et al. 2000, pp. 229–240
  17. ^ Chouteau, Barabé & Gibernau 2006, p. 818
  18. ^ Barabé, Gibernau & Forest 2002, p. 80
  19. ^ Gibernau et al. 1999, p. 1135
  20. ^ Gonçalves 1997, p. 500
  21. ^ Vieira & Izar 1999, pp. 75–82
  22. ^ Gorchov et al. 1995, p. 240
  23. ^ Gibernau et al. 2002, pp. 1017–1023
  24. ^ Mayo 1990, pp. 38–39
  25. ^ Sakuragui & Sakuragui 2001, p. 102
  26. ^ Mayo 1990, pp. 45–49
  27. ^ Schott 1832
  28. ^ Schott 1856
  29. ^ Schott 1860
  30. ^ Gauthier, Barabé & Bruneau 2008, pp. 13–27
  31. ^ Mayo 1990, pp. 37–71
  32. PMID 29750071
    .
  33. ^ Croat 1997, p. 311–704
  34. ^ Gibernau & Barabé 2000, p. 688
  35. PMID 29995336
    .
  36. ^ Gonçalves & Mayo 2000, p. 483
  37. ^ Croat & Yu 2006, p. 892
  38. ^ Croat, Mora & Kirkman 2007, p. 322
  39. ^ Foxcroft, Richardson & Wilson 2008, p. 44
  40. ^ Richard-Hansen, Bello & Vié 1998, p. 547
  41. ^ Mayo 1991, p. 624
  42. ^ Murphy & Breed 2008, p. 40
  43. ^ Gibernau et al. 1999, p. 1141
  44. ^ Gottsberger & Silberbauer-Gottsberger 1991, p. 26
  45. ^ Seymour & Gibernau 2008, pp. 1353–1354
  46. ^ Gibernau & Barabé 2000, pp. 685–689
  47. ^ Swithinbank 2005, p. 97
  48. ^ "Philodendron". The Terrarium. Retrieved 2023-09-19.
  49. ^ Frohne & Pfänder 2005, pp. 73–74
  50. ^ McIntire, Guest & Porterfield 1990
  51. ^ Mrvos, Dean & Krenzelok 1991, p. 490
  52. ^ Greer 1961
  53. ^ a b Sellers et al. 1978, pp. 92–96
  54. ^ Der Marderosian, Giller & Roia Jr. 1976, pp. 939–953
  55. ^ Plowman 1969, p. 110
  56. ^ Plowman 1969, p. 111

References

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