Sassafras

Cassytha filiformis

Leaves of Cinnamomum tamala - (malabathrum or tejpat)

Lindera triloba leaves

The Lauraceae are the laurel family, that includes the true laurel and its closest relatives. The family comprises over 3000 species of flowering plants in over 50 genera worldwide. They occur mainly in warm temperate and tropical regions, especially Southeast Asia and South America. Many are aromatic evergreen trees or shrubs, but some, such as Sassafras, are deciduous, or include both deciduous and evergreen trees and shrubs, especially in tropical and temparate climates. Cassytha is a genus unique to the Lauraceae family in that it is a genus of parasitic vines.

Overview[edit]

The family has a worldwide distribution in tropical and warm climates. The Lauraceae are important components of tropical forests ranging from low-lying to montane. In several forested regions, Lauraceae are among the top five families in terms of the number of species present.

The Lauraceae give their name to habitats known as laurel forests, which have many trees that superficially resemble the Lauraceae, though they may belong to other plant families such as Magnoliaceae or Myrtaceae. Laurel forests of various types occur on most continents and on many major islands.

Although the taxonomy of the Lauraceae is still not settled, conservative estimates suggest some 52 genera worldwide, including 3000 to 3500 species.^[2] Compared to other plant families, the taxonomy of Lauraceae still is poorly understood. This is partly due to its great diversity, the difficult of identifying the species, and partly because of inadequate investment in taxonomic work.^[2]

Recent monographs on small and medium-sized genera of Lauraceae (up to about 100 species) have revealed many new species.^[2] Similar increases in the numbers of species recognised in other larger genera are to be expected.^[2]

Description[edit]

Most of the Lauraceae are evergreen trees in habit. Exceptions include some two dozen species of Cassytha, all of which are obligately parasitic vines.

The fruits of Lauraceae are drupes, one-seeded fleshy fruit with a hard layer, the endocarp, surrounding the seed. However, the endocarp is very thin, so the fruit resemble a one-seeded berry.^[3] The fruit in some species (particularly in the genera Ocotea and Oreodaphne) are partly immersed or covered in a cup-shaped or deep thick cupule, which is formed from the tube of the calyx where the peduncle joins the fruit; this gives the fruit an appearance similar to an acorn. In some Lindera species, the fruit have a hypocarpium at the base of the fruit.

Distribution and uses[edit]

Because the family is so ancient and was so widely distributed on the Gondwana supercontinent, modern species commonly occur in relict populations isolated by geographical barriers, for instance on islands or tropical mountains. Relict forests retain endemic fauna and flora in communities of great value in inferring the palaeontological succession and climate change that followed the breakups of the supercontinents.

• Many Lauraceae contain high concentrations of essential oils, some of which are valued for spices and perfumes. Within the plants, most such substances are components of irritant or toxic sap or tissues that repel or poison many herbivorous or parasitic organisms.
• Some of the essential oils are valued as fragrances, such as in the traditional laurel wreath of classical antiquity, or in cabinet making, where the fragrant woods are prized for making insect-repellant furniture chests.
• Some are valued in cooking, for example, bay leaves are a popular ingredient in European, American, and Asian cuisines.
• Avocados are important oil-rich fruit that are cultivated in warm climates around the world.
• Many species are exploited for timber.
• Some species are valued as sources of medicinal material.

These genera include some of the best-known species of particular commercial value:

• Cinnamomum: cinnamon, cassia and camphor laurel
• Laurus: bay laurel
• Persea: avocado

Loss of habitat and overexploitation for such products has put many species in danger of extinction as a result of overcutting, extensive illegal logging, and habitat conversion.^[4][5][6][7]

Conversely, some species, though commercially valuable in some countries, are regarded as aggressive invaders in other regions. For example, Cinnamomum camphora, though a valued ornamental and medicinal plant, is so invasive as to have been declared a weed in subtropical forested areas of South Africa.^[8]

Ecology[edit]

Lindera melissifolia: This endangered species is native to the southeastern United States, and its demise is associated with habitat loss from extensive drainage of wetlands for agriculture and forestry.^[9]

Lauraceae flowers are protogynous, often with a complex flowering system to prevent inbreeding. The fruits are an important food source for birds, on which some Palaeognathae are highly dependent.^{[citation needed]} Other birds that rely heavily on the fruit for their diets include members of the families Cotingidae, Columbidae, Trogonidae, Turdidae, and Rhamphastidae, amongst others. Birds that are specialised frugivores tend to eat the whole fruit and regurgitate seeds intact, thereby releasing the seeds in favourable situations for germination (ornithochory). Some other birds that swallow the fruit pass the seed intact through their guts.

Seed dispersal of various species in the family is also carried out by monkeys, arboreal rodents, porcupines, opossums, and fishes.^{[citation needed]}Hydrochory occurs in Caryodaphnopsis.^{[10][dubious – discuss]}

The leaves of some species in the Lauraceae have domatia in the axils of their veins. The domatia are home to certain mites. Other lauraceous species, members of the genus Pleurothyrium in particular, have a symbiotic relationship with ants that protect and defend the tree. Some Ocotea species are also used as nesting sites by ants, which may live in leaf pockets or in hollowed-out stems.^[11]

Defense mechanisms that occur among members of the Lauraceae include irritant or toxic sap or tissues that repel or poison many herbivorous organisms.

Trees of the family predominate in the world's laurel forests^{[citation needed]} and cloud forests,^{[citation needed]} which occur in tropical to mild temperate regions of both northern and southern hemispheres. Other members of the family however, occur pantropically in general lowland and Afromontane forest, and in Africa for example there are species endemic to countries such as Cameroon, Sudan, Tanzania, Uganda and Congo. Several relict species in the Lauraceae occur in temperate areas of both hemispheres. Many botanical species in other families have similar foliage to the Lauraceae due to convergent evolution, and forests of such plants are called laurel forest. These plants are adapted to high rainfall and humidity, and have leaves with a generous layer of wax, making them glossy in appearance, and a narrow, pointed-oval shape with a 'drip tip', which permits the leaves to shed water despite the humidity, allowing transpiration to continue. Scientific names similar to Daphne (e.g., Daphnidium, Daphniphyllum)^[12] or "laurel" (e.g.,Laureliopsis, Skimmia laureola) indicate other plant families that resemble Lauraceae.

Some Lauraceae species have adapted to demanding conditions in semiarid climates, but they tend to depend on favorable edaphic conditions, for example, perennial aquifers, periodic groundwater flows, or periodically flooded forests in sand that contains hardly any nutrients. Various species have adapted to swampy conditions by growing pneumatophores, roots that grow upward, that project above the levels of periodic floods that drown competing plants which lack such adaptations.^{[citation needed]}

Paleobotanists have suggested the family originated some 174±32 million years ago (Mya), while others^[13] do not believe they are older than the mid-Cretaceous. Fossil flowers attributed to this family occur in Cenomanian clays (mid-Cretaceous, 90-98 Mya) of the Eastern United States (Mauldinia mirabilis). Fossils of Lauraceae are common in the Tertiary strata of Europe and North America, but they virtually disappeared from central Europe in the Late Miocene.^{[citation needed]} Because of their unusual fragility, the pollens of Lauraceae do not keep well and have been found only in relatively recent strata.

Deciduous Lauraceae lose all of their leaves for part of the year depending on variations in rainfall. The leaf loss coincides with the dry season in tropical, subtropical, and arid regions.

Classification[edit]

Twig of Ocotea obtusata with unripe fruit with an appearance similar to an acorn

Cassytha filiformis fruits

Classification within the Lauraceae is not fully resolved. Multiple classification schemes based on a variety of morphological and anatomical characteristics have been proposed, but none are fully accepted. According to Judd et al. (2007),^[14] the suprageneric classification proposed by van der Werff and Richter (1996)^[15] is currently the authority. However, due to an array of molecular and embryological evidence that disagrees with the groupings, it is not fully accepted by the scientific community. Their classification is based on inflorescence structure and wood and bark anatomy. It divides Lauraceae into two subfamilies, Cassythoideae and Lauroideae. The Cassythoideae comprise a single genus, Cassytha, and are defined by their herbaceous, parasitic habit. The Lauroideae are then divided into three tribes: Laureae, Perseeae, and Cryptocaryeae.

The subfamily Cassythoideae is not fully supported. Backing has come from matK sequences of chloroplast genes^[16] while a questionable placement of Cassytha has been concluded from analysis of intergenetic spacers of chloroplast and nuclear genomes.^[17] Embryological studies also appear contradictory. One study by Heo et al. (1998)^[18] supports the subfamily. It found that Cassytha develops an ab initio cellular-type endosperm and the rest of the family (with one exception) develops a nuclear-type endosperm. Kimoto et al. (2006)^[19] suggest Cassytha should be placed in the Cryptocaryeae tribe because it shares a glandular anther tapetum and an embryo sac protruding from the nucellus with other members of the Cryptocaryeae.

The Laureae and Perseeae tribes are not well supported by any molecular or embryological studies. Sequences of the matK chloroplast gene,^[16] as well as sequences of chloroplast and nuclear genomes,^[17] reveal close relationships between the two tribes. Embryological evidence does not support a clear division between the two tribes, either. Genera such as Caryodaphnopsis and Aspidostemon that share embryological characteristics with one tribe and wood and bark characteristics or inflorescence characteristics with another tribe blur the division of these groups.^[18] All available evidence, except for inflorescence morphology and wood and bark anatomy, fails to support separate Laureae and Perseeae tribes.

The Cryptocaryeae tribe is partially supported by molecular and embryological studies. Chloroplast and nuclear genomes support a tribal grouping that contains all the genera circumscribed by van der Weff and Richter (1996),^[15] as well as three additional genera.^[17] Partial support for the tribe is also attained from the matK sequences of chloroplast genes^[16] as well as embryology.^[20]

Challenges in Lauraceae classification

The knowledge of the species comprising the Lauraceae is incomplete. In 1991, about 25-30% of neotropical Lauraceae species had not been described.^[21] In 2001, embryological studies had only been completed on individuals from 26 genera yielding a 38.9% level of knowledge, in terms of embryology, for this family.^[20] Additionally, the huge amount of variation within the family poses a major challenge for developing a reliable classification.^[15][21]

Phytochemistry[edit]

The adaptation of Lauraceae to new environments has followed a long evolutionary journey which has led to many specializations, including defensive or deterrent systems against other organisms.

Phytochemicals in the Lauraceae are numerous and diverse. Benzylisoquinoline alkaloids include aporphines and oxoaporphines, as well as derivatives of morphinans. Essential oils include terpenoids, benzyl benzoates, allylphenols, and propenylphenols. Lignans and neolignans are present, along with S-methyl-5-O-flavonoids, proanthocyanidins, cinnamoylamides, phenylpyrroles, styryl pyrones, polyketides (acetogenins), furanosesquiterpenes, and germacranolidous, heliangolidous, eudesmanolidous and guaianolidous sesquiterpene lactones.^{[citation needed]}

Genera[edit]

Recent taxonomic revisions of the family include these genera:^[22]

These genera have traditionally been considered separate within Lauraceae, but have not been re-evaluated recently:^[22]Acrodiclidium, Adenodaphne, Afrodaphne, Agathophyllum, Aperiphracta, Aydendron, Balanopsis, Bihania, Bryantea, Calosmon, Camphoromoea, Cedrota, Ceramocarpium, Ceramophora, Chanekia, Clinostemon, Cyanodaphne, Cylicodaphne, Damburneya, Daphnidium, Drimophyllum, Euosmus, Euphoebe, Fiwa, Goeppertia, Gymnobalanus, Haasia, Iozoste, Jozoste, Lepidadenia, Leptodaphne, Linharea, Menestrata, Micropora, Miscanteca, Nesodaphne, Ozanthes, Ozarthris, Pipalia, Pseudocryptocarya, Sebifera, Silvia, Strychnodaphne, Tamala, Temmodaphne, Triadodaphne, Tylostemon

References[edit]

Wikimedia Commons has media related to Lauraceae.

Wikispecies has information related to: Lauraceae

1. ^ Angiosperm Phylogeny Group (2009). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III" (PDF). Botanical Journal of the Linnean Society 161 (2): 105–121. doi:10.1111/j.1095-8339.2009.00996.x. Retrieved 2013-07-06. 
2. ^ ^{a b c d} "Lauraceæ Columbianæ". 
3. ^ Little, S.A.; Stockey, R.A.; Penner, B. (2009). "Anatomy and development of fruits of Lauraceae from the Middle Eocene Princeton Chert". American Journal of Botany 96 (3): 637–651. doi:10.3732/ajb.0800318. PMID 21628220. 
4. ^ "Ocotea argylei". Iucnredlist.org. 1998-01-01. Retrieved 2014-05-10. 
5. ^ "Ocotea basicordatifolia". Iucnredlist.org. 1998-01-01. Retrieved 2014-05-10. 
6. ^ "Actinodaphne albifrons". Iucnredlist.org. 1998-01-01. Retrieved 2014-05-10. 
7. ^ "Actinodaphne cuspidata". Iucnredlist.org. 1998-01-01. Retrieved 2014-05-10. 
8. ^ Henderson, L. "Alien weeds and Invasive Plants" Agricultural Research Council, Agricultural Research Council, Pretoria South Africa, ISBN 1-86849-192-7
9. ^ US Fish and Wildlife Service: Species Recovery Plan: Lindera melissifolia.
10. ^ "Lauraceae". Es.scribd.com. 2011-11-25. Retrieved 2014-05-10. 
11. ^ Jean Stout 1979. An Association of an Ant, a Mealy Bug, and an Understory Tree from a Costa Rican Rain Forest. Biotropica Vol. 11, No. 4, pp. 309-311 first page available Retrieved May 22, 2012
12. ^ Sunset Western Garden Book, 1995:606–607
13. ^ Li et al.2004
14. ^ Judd, Walter, S.; Christopher Campbell; Elizabeth Kellog; Peter Stevens; Michael Donoghue (2007). Plant Systematics a Phylogenetic Approach, third edition. Massachusetts, USA: Sinauer Associates, Inc. ISBN 978-0-87893-407-2. 
15. ^ ^{a b c} H van der Werff and J.G. Richter (1996). "Toward an improved classification of Lauraceae". Annals of the Missouri Botanical Garden (Annals of the Missouri Botanical Garden, Vol. 83, No. 3) 83 (3): 409–418. doi:10.2307/2399870. JSTOR 2399870. 
16. ^ ^{a b c} Rohwer, J.G. (2000). "Toward a phylogenetic classification of the Lauraceae: evidence from matK sequences". Systematic Botany (Systematic Botany, Vol. 25, No. 1) 25 (1): 60–71. doi:10.2307/2666673. JSTOR 2666673. 
17. ^ ^{a b c} Chanderbali, A.S.,van der Werff,H. and Renner, S.S. (2001). "Phylogeny and historical biogeography of Lauraceae: Evidence from the chloroplast and nuclear genomes". Annals of the Missouri Botanical Garden (Annals of the Missouri Botanical Garden, Vol. 88, No. 1) 88 (1): 104–134. doi:10.2307/2666133. JSTOR 2666133. 
18. ^ ^{a b} Heo,K.,van der Werff, H., and Tobe, H. (1998). "Embryology and relationships of Lauraceae(Laurales)". Botanical Journal of the Linnean Society 126 (4): 295–322. doi:10.1006/bojl.1997.0138. 
19. ^ Kimoto,Y.,Utame N., and Tobe, H. (2006). "Embryology of Eusideroxylon (Cryptocaryeae, Lauraceae) and character evolution in the family". Botanical Journal of the Linnean Society 150 (2): 187–201. doi:10.1111/j.1095-8339.2006.00458.x. 
20. ^ ^{a b} Kimoto,Y.,and H. Tobe (2001). "Embryology of Laurales: a review and perspectives". Journal of Plant Research 114 (3): 247–261. doi:10.1007/PL00013988. 
21. ^ ^{a b} Rohwer, J. G.,H. Richter, and H. van der Werff (1991). "Two new genera of neotropical Lauraceae and critical remarks on the generic delimitation". Annals of the Missouri Botanical Garden (Annals of the Missouri Botanical Garden, Vol. 78, No. 2) 78 (2): 388–4oo. doi:10.2307/2399568. JSTOR 2399568. 
22. ^ ^{a b} "The Plant List". Retrieved 5 February 2014. 

• Lauraceae in L. Watson and M.J. Dallwitz (1992 onwards). The families of flowering plants.
• Kostermans, André Joseph Guillaume Henri (1957). "Lauraceae". Reinwardtia 4 (2): 193–256. 
• Meissner (né Meisner), Carl Daniel Friedrich 1864. Lauraceae (Ordo 162) in A. L. P. P. de Candolle (ed.), Prodromus Systematis Universalis Regni Vegetabilis 15(1): 1-260, Parisiis [Paris], Victoris Masson et Filii.
• Mez, Carl Christian (1889). "Lauraceae Americanae Monographice Descripsit". Jahrbuch des Königlichen Botanischen Gartens und des Botanischen Museums zu Berlin 5: 1–556. 
• Nees von Esenbeck, Christian Gottfried Daniel (1836): Systema Laurinarum, Berlin, Veitii et Sociorum. Until the page 352, available, free, on pdf files in Gallica
• Rohwer, Jens G. in Kubitzki, K.(Editor) 1993. The Families and Genera of Vascular Plants, Vol.2: K. Kubitzki, J. G. Rohwer & V. Bittrich, 366-390. ISBN 3-540-55509-9
• Wagner, W. L., D. R. Herbst, and S. H. Sohmer. 1990. Manual of the Flowering Plants of Hawai'i. Spec. Publ. 83. University of Hawaii Press and Bishop Museum Press. Bishop Museum. 1854 pp.

Sassafras albidum (Sassafras, White Sassafras, Red Sassafras, or Silky Sassafras) is a species of Sassafras native to eastern North America, from southern Maine and southern Ontario west to Iowa, and south to central Florida and eastern Texas. It occurs throughout the eastern deciduous forest habitat type, at altitudes of sea level up to 1,500 m.^[2][3][4] It formerly also occurred in southern Wisconsin, but is extirpated there as a native tree.^[5]

Description[edit]

It is a medium-sized deciduous tree growing to 15–20^[6][7][8] m tall, with a trunk up to 60 cm diameter, and a crown with many slender branches. The bark on trunk of mature trees is thick, dark red-brown, and deeply furrowed. The branching is sympodial. The shoots are bright yellow green at first with mucilaginous bark, turning reddish brown, and in two or three years begin to show shallow fissures. The leaves are alternate, green to yellow-green, ovate or obovate, 10–16 cm long and 5–10 cm broad with a short, slender, slightly grooved petiole. They come in three different shapes, all of which can be on the same branch; three-lobed leaves, unlobed elliptical leaves, and two-lobed leaves; rarely, there can be more than three lobes. In fall, they turn to shades of yellow, tinged with red. The flowers are produced in loose, drooping, few-flowered racemes up to 5 cm long in early spring shortly before the leaves appear; they are yellow to greenish-yellow, with five or six tepals. It is usually dioecious, with male and female flowers on separate trees; male flowers have nine stamens, female flowers with six staminodes (aborted stamens) and a 2–3 mm style on a superior ovary. Pollination is by insects. The fruit is a dark blue-black drupe 1 cm long containing a single seed, borne on a red fleshy club-shaped pedicel 2 cm long; it is ripe in late summer, with the seeds dispersed by birds. The cotyledons are thick and fleshy. All parts of the plant are aromatic and spicy. The roots are thick and fleshy, and frequently produce root sprouts which can develop into new trees.^{[2][3][4][9][10]}

Ecology[edit]

It prefers rich, well-drained sandy loam with a pH of 6–7, but will grow in any loose, moist soil. Seedlings will tolerate shade, but saplings and older trees demand full sunlight for good growth; in forests it typically regenerates in gaps created by windblow. Growth is rapid, particularly with root sprouts, which can reach 1.2 m in the first year and 4.5 m in 4 years. Root sprouts often result in dense thickets, and a single tree, if allowed to spread unrestrained, will soon be surrounded by a sizable clonal colony, as its stoloniferous roots extend in every direction and send up multitudes of shoots.^[3][4][9]

Uses[edit]

Parc Oberthür, Rennes

Cultivation[edit]

Sassafras is often grown as an ornamental tree for its unusual leaves and aromatic scent. Outside of its native area, it is occasionally cultivated in Europe and elsewhere.^[3]

Wood[edit]

The wood is dull orange brown, hard, and durable in contact with the soil; it was used in the past for posts and rails, small boats and ox-yokes, though scarcity and small size limits current use. Some is still used for making furniture.^[11]

Medicinal and food uses[edit]

An essential oil, called sassafras oil, is distilled from the root bark or the fruit. It was used as a fragrance in perfumes and soaps, food (sassafras tea and candy flavoring) and for aromatherapy. The smell of sassafras oil is said to make an excellent repellent for mosquitoes and other insects,^{[citation needed]} which makes it a nice garden plant. Acids can be extracted from bark for manufacturing perfumes.

The essential oil was used as a pain killer as well as an antiseptic in dentistry.^{[citation needed]} The pith is used in the U.S. to soothe eye inflammation and ease catarrh.

Sassafras oil is the preferred source of safrole, which is the main component (75–80%) of the essential oil.^[12]

The root or root bark is used to make tea, although most commercial "sassafras teas" are now artificially flavored as a result of the FDA ban (see below). A yellow dye is obtained from the wood. The shoots were used to make root beer, a traditional soft drink beverage carbonated with yeast, which owed its characteristic odor and flavor to the sassafras extract. Most commercial root beers have replaced the sassafras extract with methyl salicylate, the ester found in wintergreen and black birch (Betula lenta) bark. A safrole-free sassafras extract is now available for flavoring.

The dried and ground leaves are known as filé powder. Filé is still used for thickening sauces and soups in Cajun, Creole, and other Louisiana cooking, notably in the dish filé gumbo.

Legislation[edit]

Safrole is now recognized by the United States Department of Agriculture as a potential carcinogen. Safrole, and sassafras not certified as safrole-free, have been banned in the United States as food additives or flavoring agents by the FDA since 1976 due to safrole's designation as a carcinogen.^[13] According to the FDA's listing, sassafras leaves “must be safrole free” to be used as food additives.

Safrole is commonly used by clandestine laboratories to synthesize various drugs such as MDA, MDMA and MDEA. For this reason, the sale of safrole and sassafras oil is monitored by the U.S. Drug Enforcement Administration.

History[edit]

The name "Sassafras", applied by the botanist Nicolas Monardes in the sixteenth century, is said to be a corruption of the Spanish word for saxifrage.

Before the twentieth century, Sassafras enjoyed a great reputation in the medical literature, but became valued for its power to improve the flavor of other medicines.^[9]

Gallery[edit]

• 

  Unilobed leaf

• 

  Bilobed leaf

• 

  Trilobed leaf

• 

  Young plant with 3 leaf varieties

• 

  Flowers

• 

  Bark

• 

  The fruit

• 

  Autumn foliage closeup

• 

  Seedling

References[edit]