The Thymelaeaceae are a cosmopolitan

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s composed of 50 genera (listed below) and 898 species.Zachary S. Rogers (2009 onwards)
A World Checklist of Thymelaeaceae (version 1)
Missouri Botanical Garden Website, St. Louis. It was established in 1789 by

Antoine Laurent de Jussieu Antoine Laurent de Jussieu (; 12 April 1748 – 17 September 1836) was a French botanist, notable as the first to publish a natural classification of flowering plants; much of his system remains in use today. His classification was based on an e ...

.Antoine Laurent de Jussieu ''Genera Plantarum'', page 76. Herrisant & Barrois, Paris. The Thymelaeaceae are mostly

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

s and

shrub A shrub or bush is a small to medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees by their multiple ...

s, with a few

vine A vine is any plant with a growth habit of trailing or scandent (that is, climbing) stems, lianas, or runners. The word ''vine'' can also refer to such stems or runners themselves, for instance, when used in wicker work.Jackson; Benjamin; Da ...

s and

herbaceous plant Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition o ...

Description

Several conspicuous or unusual traits are characteristic of the family (when ''Tepuianthus'' is excluded). The bark is usually shiny and fibrous, with strips of bark peeling down the side of broken stems.Ernst Schmidt, Mervyn Lotter and Warren McCleland The number of

stamen The stamen (: stamina or stamens) is a part consisting of the male reproductive organs of a flower. Collectively, the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filament ...

s is usually once or twice the number of calyx lobes; when twice, they often occur in two well separated series. Exceptions include ''Gonystylus'', which may have up to 100 stamens, and ''Pimelea'', which has only 1 or 2. Thymelaeaceae are often difficult to identify because of equivocal interpretation of the flower parts. Sepals, petals, and

staminode In botany, a staminode is an often rudimentary, sterile or abortive stamen, which means that it does not produce pollen.Jackson, Benjamin, Daydon; ''A Glossary of Botanic Terms with their Derivation and Accent''; Published by Gerald Duckworth & Co ...

s are hard to distinguish, and many keys are ambiguous about whether staminodes should be counted as stamens. Moreover, in ''Wikstroemia'', individual plants often produce anomalous flowers.

Taxonomy

The family is named for the genus '' Thymelaea'', the name of which is a combination of the Greek name for the herb

thyme Thyme () is a culinary herb consisting of the dried aerial parts of some members of the genus ''Thymus (plant), Thymus'' of flowering plants in the mint family Lamiaceae. Thymes are native to Eurasia and north Africa. Thymes have culinary, medici ...

θύμος (thúmos) and that for the

olive The olive, botanical name ''Olea europaea'' ("European olive"), is a species of Subtropics, subtropical evergreen tree in the Family (biology), family Oleaceae. Originating in Anatolia, Asia Minor, it is abundant throughout the Mediterranean ...

ἐλαία (elaía)—in reference to its thyme-like foliage (i.e. minuscule leaves) and olive-like fruit.

Classification

The Thymelaeaceae are in the order

Malvales The Malvales are an Order (biology), order of flowering plants. As circumscribed by Angiosperm Phylogeny Group, APG II-system, the order includes about 6000 species within nine Family (biology), families. The order is placed in the eurosids II, w ...

.Peter F. Stevens (2001 onwards) Angiosperm Phylogeny Website In: Missouri Botanical Garden Website Except for a sister relationship with Tepuianthaceae, little is known for sure about their relationships with the other families in the order.Clemens Bayer, Michael F. Fay, Anette Y. de Bruijn, Vincent Savolainen, Cynthia M. Morton, Klaus Kubitzki, William S. Alverson, and Mark W. Chase (1999). "Support for an expanded family concept of Malvaceae within a recircumscribed order Malvales: a combined analysis of plastid atpB and rbcL DNA sequences". ''Botanical Journal of the Linnean Society'' 129(4): 267-381 Unlike most recent authors, who recognize four subfamilies, B.E. Herber has divided Thymelaeaceae into two subfamilies. He has retained the subfamily Gonostyloideae, but renamed it Octolepidoideae. The other three traditional subfamilies (Synandrodaphnoideae, Aquilarioideae, and Thymelaeoideae) were combined into a Thymelaeoideae s.l.( sensu lato), and reduced to

tribal The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide use of the term in English is in the discipline of anthropology. The definition is contested, in part due to conflict ...

rank, as Synandrodaphneae, Aquilarieae, and Daphneae, respectively. No tribes were designated in subfamily Octolepidoideae, but it was provisionally divided into two informal groups, the Octolepis group and the Gonystylus group. Likewise, no

subtribes Subtribe is a taxonomic category ranking which is below the rank of tribe and above genus. The standard suffix for a subtribe is -ina (in animals) or -inae (in plants). The first use of this word dates back to the late 19th century. An example of ...

were designated in the tribe Daphneae, but it was informally divided into four groups: the ''Linostoma'' group, the ''Daphne'' group, the ''Phaleria'' group, and the ''Gnidia'' group. The 45 genera recognized by Herber are grouped as follows. Three genera in Daphneae were placed

incertae sedis or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...

(not assigned to any particular group or in a separate group by themselves).

Octolepidoideae

:''Octolepis'' group: '' Arnhemia'', '' Deltaria'', ''

Lethedon ''Lethedon'' is a genus of shrubs in the Thymelaeaceae family native to Queensland, New Caledonia, and Vanuatu. It is related to ''Arnhemia (plant), Arnhemia'', ''Deltaria'', ''Gonystylus'' and ''Solmsia''.Beaumont, A. J., T. J. Edwards, J. Manni ...

'', '' Octolepis'', '' Solmsia'' :''Gonystylus'' group: '' Aetoxylon'', '' Amyxa'', '' Gonystylus''

Thymelaeoideae Thymelaeoideae is a Subfamily (biology), subfamily of the Thymelaeaceae family. Taxonomy :Synandrodaphneae: ''Synandrodaphne'' :Aquilarieae: ''Aquilaria'', ''Gyrinops'' :Daphneae ::''Linostoma'' group: ''Craterosiphon'', ''Dicranolepis'', ''Enkl ...

:Synandrodaphneae: '' Synandrodaphne'' :Aquilarieae: ''

Aquilaria ''Aquilaria'' is a genus of trees, called lign aloes or lign-aloes trees, in the family Thymelaeaceae. It includes 21 species native to southeast Asia. They occur particularly in the rainforests of Indonesia, Thailand, Cambodia, Laos, Vietnam, s ...

'', ''

Gyrinops ''Gyrinops'' is a genus of nine species of trees, called lign aloes or lign-aloes trees, in the family Thymelaeaceae. They are native to Southeast Asia, the Indian Subcontinent, and New Guinea. The genus ''Gyrinops'' is closely related to ''Aqui ...

'' :Daphneae ::''Linostoma'' group: '' Craterosiphon'', '' Dicranolepis'', '' Enkleia'', '' Jedda'', '' Linostoma'', '' Lophostoma'', '' Synaptolepis'' ::''Phaleria'' group: '' Peddiea'', '' Phaleria'' ::''Daphne'' group: '' Daphne'', '' Daphnopsis'', '' Diarthron'', '' Dirca'', '' Edgeworthia'', '' Funifera'', '' Goodallia'', '' Lagetta'', '' Ovidia'', '' Rhamnoneuron'', '' Schoenobiblus'', '' Stellera'', '' Thymelaea'', '' Wikstroemia'' ::''Gnidia'' group: ''

Dais A dais or daïs ( or , American English also but sometimes considered nonstandard)dais
in the Random House Dictionary< ...

'', '' Drapetes'', '' Gnidia'', '' Kelleria'', '' Lachnaea'', ''

Passerina The genus ''Passerina'' is a group of birds in the cardinal family (Cardinalidae). Although not closely related to the buntings in the family Emberizidae, they are sometimes known as the North American buntings. The males show vivid colors i ...

'', '' Pimelea'', '' Struthiola'' ::Incertae sedis: '' Linodendron'', '' Stephanodaphne'', '' Lasiadenia''

Phylogeny

The first molecular phylogeny for Thymelaeaceae was published in 2002. It was based on two regions of

chloroplast A chloroplast () is a type of membrane-bound organelle, organelle known as a plastid that conducts photosynthesis mostly in plant cell, plant and algae, algal cells. Chloroplasts have a high concentration of chlorophyll pigments which captur ...

DNA Deoxyribonucleic acid (; DNA) is a polymer composed of two polynucleotide chains that coil around each other to form a double helix. The polymer carries genetic instructions for the development, functioning, growth and reproduction of al ...

. These were the rbcL

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

and the intergenic spacer between the

transfer RNA Transfer ribonucleic acid (tRNA), formerly referred to as soluble ribonucleic acid (sRNA), is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes). In a cell, it provides the physical link between the gene ...

genes trnL and trnF. Forty one species in the family were sampled. In 2008, Marline Rautenbach performed a phylogenetic study in which 143 species in the family were sampled. The sampling in this study was concentrated in the ''Gnidia'' group, but the sampling in the rest of the family was as extensive as in the previous study, or more so. In addition to rbcL and trnL-F data, sequences of the ITS (

internal transcribed spacer Internal transcribed spacer (ITS) is the spacer DNA situated between the small-subunit ribosomal RNA (rRNA) and large-subunit rRNA genes in the chromosome or the corresponding transcribed region in the polycistronic rRNA precursor transcript. ...

) region of nrDNA ( nuclear ribosomal DNA) were used. All of the clades that were strongly supported in the previous study were recovered with even stronger statistical support. The tree below is an excerpt from the Rautenbach (2002) phylogeny. The species of ''Gnidia'' were chosen from among the most common or well known species in a way that shows which clades contain species of ''Gnidia''.

Defining the genera

The circumscription of genera in Thymelaeaceae has always been especially difficult, and is to some degree artificial. For example, the difficulty of distinguishing ''Daphne'' from ''Wikstroemia'' has been commented upon by Rautenbach and Herber. Several small genera are probably embedded in ''Daphne'' or ''Wikstroemia'', or if ''Daphne'' and ''Wikstroemia'' are intermingled, these small genera might be embedded in both simultaneously. ''Stellera'', for example, is nested within ''Wikstroemia'', at least (see the

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

tree below). A recent comparison of DNA sequences has established the

monophyly In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent comm ...

of ''Thymelaea'' and the

polyphyly A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as homoplasies, which ar ...

of ''Diarthron'',David Galicia-Herbada (2006). "Origin and diversification of Thymelaea(Thymelaeaceae): inferences from a phylogenetic study based on ITS (rDNA) sequences". ''Plant Systematics and Evolution'' 257(3-4):159-187. but there was not sufficient sampling in ''Wikstroemia'' and ''Daphne'' to exclude the possibility that ''Thymelaea'', ''Diarthron'', and others might be embedded in them. The large genus ''Gnidia'' is polyphyletic and its species fall into 4 separate clades, each of which contains other genera of the family (see the phylogenetic tree below). The

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

for ''Gnidia'' is '' Gnidia pinifolia''. If ''Gnidia'' is divided into 4 or more separate genera, the segregate genus which contains ''G. pinifolia'' will retain the name ''Gnidia''. Zachary S. Rogers published a revision of the ''Gnidia'' of Madagascar in 2009 in '' Annals of the Missouri Botanical Garden''. Some of the older treatments of Thymelaeaceae recognize ''Lasiosiphon'' as a separate genus from ''Gnidia''. This distinction was later shown to be artificial. However, Van der Bank et al. (2002)Michelle van der Bank, Michael F. Fay, and Mark W. Chase (2002). "Molecular Phylogenetics of Thymelaeaceae with particular reference to African and Australian genera". ''Taxon'' 51(2):329-339. suggested that ''Lasiosiphon'' might be resurrected if redefined. The type species for ''Lasiosiphon'' is ''Gnidia glauca'', formerly known as ''Lasiosiphon glaucus''.

Open questions

Rautenbach used different names from Herber for some of the groups and placed some of the groups at different taxonomic rank, but her phylogeny supports Herber's classification with the few exceptions noted below. The only strongly supported difference (99% (bootstrap percentage) from Herber's classification was that ''Dais'' was found to be sister to ''Phaleria''. The phylogeny casts significant doubt upon the monophyly of the subfamily Octolepidoideae, and upon the monophyly of the informal ''Octolepis'' and ''Gonostylus'' groups, but this result had only weak statistical support. Only a sampling of more species and more DNA from each will determine whether these groups are monophyletic or not. ''Stephanodaphne'' and ''Peddiea'' might need to be transferred to the ''Gnidia'' group, but support was not strong (60% BP) for a clade consisting of the ''Gnidia'' group with ''Stephanodaphne'' and ''Peddiea''. Again, more extensive sampling will be required to resolve this question. Two of the 3 genera placed incertae sedis by Herber (''Linodendron'' and ''Lasiadenia'') have not yet been sampled and their relationships to other genera remain obscure.

Genera

Herber (2003)B.E. Herber. "Thymelaeaceae" In: ''The Families and Genera of Vascular Plants vol.V'' (Klaus Kubitzki and Clemens Bayer, volume editors). Springer-Verlag: Berlin, Heidelberg (2003) recognized 45 genera, excluding '' Tepuianthus'' from the family, sinking ''Atemnosiphon'' and ''Englerodaphne'' into ''Gnidia'', ''Eriosolena'' into ''Daphne'', and ''Thecanthes'' into ''Pimelea''. The largest genera and the approximate number of species in each are ''Gnidia'' (160), ''Pimelea'' (110), ''Daphne'' (95), ''Wikstroemia'' (70), ''Daphnopsis'' (65), ''Struthiola'' (35), ''Lachnaea'' (30), ''Thymelaea'' (30), ''Phaleria'' (30), and ''Gonystylus'' (25). , ''

Plants of the World Online Plants of the World Online (POWO) is an online taxonomic database published by the Royal Botanic Gardens, Kew. History Following the Convention on Biological Diversity, the Royal Botanic Gardens in Kew launched Plants of the World Online i ...

'' accepts 52 genera. In the past, different authors have defined Thymelaeaceae in different ways. For example, John Hutchinson excluded ''Gonystylus'' and its close relatives, as well as ''Aquilaria'' and its close relatives from the family, forming 2 segregate families: Gonystylaceae and Aquilariaceae.Hutchinson, John. ''The Families of Flowering Plants, Third Edition (1973)''. Oxford University Press: London. But today, the only controversy that still remains over the circumscription of the family is the question of whether '' Tepuianthus'' should be included, or segregated as a separate, monogeneric family.Horn, J.W., (2004). "The morphology and relationships of the Sphaerosepalaceae(Malvales)". ''Botanical Journal of the Linnean Society'' 144(1):1-40 Stevens includes ''Tepuianthus'', but Kubitzki treats Tepuianthaceae as a separate family.Klaus Kubitzki. "Tepuianthaceae" In: ''The Families and Genera of Vascular Plants, vol.V'' Klaus Kubitzki and Clemens Bayer. (volume editors). Springer-Verlag: Berlin, Heidelberg. (2003).

Distribution

The family is more diverse in the Southern Hemisphere than in the Northern, with major concentrations of species in

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

and

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

.Vernon H. Heywood, Richard K. Brummitt, Alastair Culham, and Ole Seberg. ''Flowering Plant Families of the World''. Firefly Books: Ontario, Canada (2007) The

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

are overwhelmingly African.Marline Rautenbach. Figure 1.2, page 7 In: "Gnidia is not monophyletic: taxonomic implications for Gnidia and its relatives in Thymelaeoideae" Digispace at the University of Johannesburg. 8 Jul 2008. (see External links below).

Ethnobotany and economic use

Several genera are of economic importance. '' Gonystylus'' (Ramin) is valued for its comparatively soft, easily worked yellowish wood, but trade in all species in the genus are controlled by

CITES CITES (shorter acronym for the Convention on International Trade in Endangered Species of Wild Fauna and Flora, also known as the Washington Convention) is a multilateral treaty to protect endangered plants and animals from the threats of inte ...

. Many genera have inner bark yielding strong fibre suitable for the making of cordage and

paper Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, Textile, rags, poaceae, grasses, Feces#Other uses, herbivore dung, or other vegetable sources in water. Once the water is dra ...

—a fact actually acknowledged in the naming of one of the genera, '' Funifera'' being the Latin for "bearer (provider) of rope". The barks of ''

'', '' Daphne'', '' Edgeworthia'', '' Gnidia'', '' Linostoma'', '' Rhamnoneuron'', '' Thymelaea'', '' Stellera'', and '' Wikstroemia'' are used in papermaking, while '' Lagetta'' was once harvested as a source of natural

lace Lace is a delicate fabric made of yarn or thread in an open weblike pattern, made by machine or by hand. Generally, lace is split into two main categories, needlelace and bobbin lace, although there are other types of lace, such as knitted o ...

for making doilies and trimmings for luxury garments.

Toxicity and medicinal uses

Many of the species (e.g. '' Wikstroemia indica'' and '' Stellera chamaejasme'') have actual or potential uses in medicine and are

poison A poison is any chemical substance that is harmful or lethal to living organisms. The term is used in a wide range of scientific fields and industries, where it is often specifically defined. It may also be applied colloquially or figurati ...

ous if eaten, acting as violent purges (e.g. '' Daphne mezereum''). This toxicity is often related to the plants' containing phorbol esters which, as the name suggests, are also common in the spurge family

Euphorbiaceae Euphorbiaceae (), the spurge family, is a large family of flowering plants. In English, they are also commonly called euphorbias, which is also the name of Euphorbia, the type genus of the family. Most spurges, such as ''Euphorbia paralias'', ar ...

Use as ornamental plants

'' Daphne'' is grown (despite the high toxicity of its attractive fruits) for its sweetly scented

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s. Species of '' Wikstroemia'', '' Daphne'', '' Phaleria'', ''

Dais A dais or daïs ( or , American English also but sometimes considered nonstandard)dais
in the Random House Dictionary< ...

'', '' Pimelea'' and other genera are grown as ornamentals.George W. Staples and Derral R. Herbst. 2005. "A Tropical Garden Flora". Bishop Museum Press: Honolulu. .Marline Rautenbach. "Gnidia is not monophyletic: taxonomic implications for Gnidia and its relatives in Thymelaeoideae". Digispace at the University of Johannesburg 8 Jul 2008. (see External links below)

Gallery

File:Strettle Road Reserve pimelea.jpg, Inflorescence of the

n '' Pimelea spectabilis'' File:Daphne striata 100604.jpg, '' Daphne striata'', native to the

Alps The Alps () are some of the highest and most extensive mountain ranges in Europe, stretching approximately across eight Alpine countries (from west to east): Monaco, France, Switzerland, Italy, Liechtenstein, Germany, Austria and Slovenia. ...

and the

Dolomites The Dolomites ( ), also known as the Dolomite Mountains, Dolomite Alps or Dolomitic Alps, are a mountain range in northeastern Italy. They form part of the Southern Limestone Alps and extend from the River Adige in the west to the Piave Va ...

File:Struthiola ciliata Gonnabos IMG 1983s.jpg, The

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

n '' Struthiola myrsinites'' File:Passerina (Thymelaeaceae) details of flowering sprig EOS 009.jpg, Flowers of an unidentified ''

'' species File:Hortus Botanicus Leiden - Phaleria capitata Jack (Sumatra).JPG, '' Phaleria capitata'' of

Sumatra Sumatra () is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the list of islands by area, sixth-largest island in the world at 482,286.55 km2 (182,812 mi. ...

exhibiting

cauliflory Cauliflory is a botanical term referring to plants that flower and fruit from their main stems or woody trunks, rather than from new growth and shoots. It is rare in temperate regions but common in tropical forests. There have been several st ...

File:Stellera chamaejasme 2.jpg, '' Stellera chamaejasme'' of Central and

East Asia East Asia is a geocultural region of Asia. It includes China, Japan, Mongolia, North Korea, South Korea, and Taiwan, plus two special administrative regions of China, Hong Kong and Macau. The economies of Economy of China, China, Economy of Ja ...

File:Daphnopsis racemosa Envira flor Oct 2007 031.jpg, Flower of '' Daphnopsis racemosa'' File:Daphnopsis racemosa Griseb. (17144500699).jpg, Fruits of ''Daphnopsis racemosa'' File:Dirca palustris - Edwards.jpg, Flowers of '' Dirca palustris'' of the US File:Akabana-mitsumata.JPG, '' Edgeworthia chrysantha'', native to China File:Wikstroemia phillyreifolia (Hawai'i false ohelo) flowers (6592426883).jpg, Flowers of the

Hawaii Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...

an '' Wikstroemia phillyreifolia''

References

External links

* Zachary S. Rogers (2009 onwards)
A Worldwide Checklist of Thymelaeaceae (version 1).

Peter F. Stevens (2001 onwards) In:

Missouri Botanical Garden The Missouri Botanical Garden is a botanical garden located at 4344 Shaw Boulevard in St. Louis, Missouri. It is also known informally as Shaw's Garden for founder and philanthropy, philanthropist Henry Shaw (philanthropist), Henry Shaw. I ...

Rautenbach (2008)
in
UJDigiSpace @ The University of Johannesburg

Distribution
in: Gnidia is not monophyletic: taxonomic implications for Gnidia and its relatives in Thymelaeoideae
Thymelaeaceae of Mongolia in FloraGREIF
{{Authority control Malvales families