Thymelaeaceae

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Thymelaeaceae
Thymelaea hirsuta kz2.jpg
Thymelaea hirsuta
Scientific classification Red Pencil Icon.png
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Malvales
Family: Thymelaeaceae
Juss.
Genera

See text

The Thymelaeaceae /ˌθɪmɪlˈs/ are a cosmopolitan family of flowering plants composed of 50 genera (listed below) and 898 species. [1] It was established in 1789 by Antoine Laurent de Jussieu. [2] The Thymelaeaceae are mostly trees and shrubs, with a few vines and herbaceous plants.

Contents

Description

This is not intended as a full botanical description, but only as a few notes on some of the conspicuous or unusual traits of the family when Tepuianthus is excluded. The bark is usually shiny and fibrous. Attempts to break the stem often result in a strip of bark peeling down the side. [3] The number of stamens is usually once or twice the number of calyx lobes. If twice, then 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. The floral tube appears to be a calyx or corolla, but is actually a hollow receptacle. [4] This feature is probably unique to Thymelaeaceae. The sepals are mounted on the rim of the floral tube. Stamens may be mounted on the rim or inside. What appear to be petals are actually stipular appendages of the sepals. The fruit is a 1-seeded berry or an achene. The 1-seeded berries have often been mistaken for drupes whenever the seed coat was mistaken for an endocarp.

When using a key to the families of flowering plants, Thymelaeaceae are often difficult or impossible to recognize because of equivocal interpretation of the flower parts. Sepals, petals, and staminodes 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. [5] In these, the nonfunctional organs are much deformed and bear little resemblance to the parts that they represent.

A good collection of pictures of plants in this family has appeared in a scientific paper. [4]

Taxonomy

The family is named for the genus Thymelaea , the name of which is a combination of the Greek name for the herb thyme θύμος (thúmos) and that for the olive ἐλαία (elaía) - in reference to its thyme-like foliage (i.e. minuscule leaves) and olive-like fruit. [6]

Classification

The Thymelaeaceae are in the order Malvales. [7] Except for a sister relationship with Tepuianthaceae, little is known for sure about their relationships with the other families in the order. [8]

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

Octolepidoideae

Octolepis group: Arnhemia , Deltaria , Lethedon , Octolepis , Solmsia
Gonystylus group: Aetoxylon , Amyxa , Gonystylus

Thymelaeoideae

Synandrodaphneae: Synandrodaphne
Aquilarieae: Aquilaria , Gyrinops
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 , Drapetes , Gnidia , Kelleria , Lachnaea , Passerina , Pimelea , Struthiola
Incertae sedis: Linodendron , Stephanodaphne , Lasiadenia

Phylogeny

The first molecular phylogeny for Thymelaeaceae was published in 2002. [9] It was based on 2 regions of chloroplast DNA. These were the rbcL gene and the intergenic spacer between the transfer RNA 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) 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.

Octolepis

Gonystylus

Lethedon

Deltaria

Solmsia

Arnhemia

Thymelaeoideae  
Synandrodaphneae  

Synandrodaphne

Aquilarieae  

Aquilaria

Gyrinops

Daphneae  
Linostoma group 

Dicranolepis

Enkleia

Synaptolepis

Craterosiphon

Daphne group 

Edgeworthia

Wikstroemia gemmata

Wikstroemia canescens

Stellera

Diarthron

Daphne

Thymelaea

Phaleria group 

Phaleria

Dais

Gnidia group 

Gnidia glauca

Gnidia kraussiana

Gnidia calocephala

Stephanodaphne

Dirca

Ovidia

Peddiea

Gnidia humilis

Gnidia squarrosa

Gnidia pilosa

Pimelea

Gnidia racemosa

Gnidia pinifolia

Struthiola

Lachnaea

Passerina

Drapetes

Gnidia anomala

Defining the genera

The striking flowers of Gnidia rubescens. Ruby Gnidia (Gnidia rubescens) close-up (11421758284).jpg
The striking flowers of Gnidia rubescens .
Gnidia pinifolia in bloom. Gnidia pinifolia Bettys Bay.jpg
Gnidia pinifolia in bloom.
Gnidia glauca (known formerly as Lasiosiphon glaucus). Gnidia glauca (6666724377).jpg
Gnidia glauca (known formerly as Lasiosiphon glaucus).
Detail of flowers of Gnidia glauca (known formerly as Lasiosiphon glaucus). Nacchinar (in Tamil) (3127220503).jpg
Detail of flowers of Gnidia glauca (known formerly as Lasiosiphon glaucus).

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. [4] [10] 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 tree below).

A recent comparison of DNA sequences has established the monophyly of Thymelaea and the polyphyly of Diarthron, [11] 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 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) [9] 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

Gonystylus bancanus native to Brunei, Indonesia, and Malaysia: botanical line drawing of detailed anatomy. Gonystylus bancanus.jpg
Gonystylus bancanus native to Brunei, Indonesia, and Malaysia: botanical line drawing of detailed anatomy.

Herber (2003) [10] recognized 45 genera, excluding Tepuianthus from the family, sinking Atemnosiphon and Englerodaphne into Gnidia, Eriosolena into Daphne, and Thecanthes into Pimelea. [10] 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). [10]

As of December 2014, 50+ genera are accepted by the World Checklist of Thymelaceae: [12]

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. [13] 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. [14] Stevens includes Tepuianthus, but Kubitzki treats Tepuianthaceae as a separate family. [15]

Distribution

The family is more diverse in the Southern Hemisphere than in the Northern, with major concentrations of species in Africa and Australia. [16] The genera are overwhelmingly African. [17]

Ethnobotany and economic use

Lagetta lagetto the Lacebark : botanical illustration showing plant with samples of cordage and fabric made from its fibre. Hooker-Lagetta lagetto.jpg
Lagetta lagetto the Lacebark : botanical illustration showing plant with samples of cordage and fabric made from its fibre.
Intricate Jamaican souvenirs woven from Lacebark fibre. Jamaican-lacebark-souvenirs2.jpg
Intricate Jamaican souvenirs woven from Lacebark fibre.
The Brazilian Funifera utilis - its genus named for the suitability of its fibre for rope-making. (Under obsolete name Lagetta funifera). Flickr - BioDivLibrary - n39 w1150 (1).jpg
The Brazilian Funifera utilis - its genus named for the suitability of its fibre for rope-making. (Under obsolete name Lagetta funifera).

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. Many genera have inner bark yielding strong fibre suitable for the making of cordage and paper - 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 , Rhamnoneuron , Thymelaea , Stellera , and Wikstroemia are used in paper-making, while Lagetta species are known as lacebark for their lacelike inner bark, the attractive appearance of which has led to their being used to make clothing and other utilitarian objects.

Toxicity and medicinal uses

The attractive, but deadly, fruits of Daphne mezereum. Daphne mezereum 003.JPG
The attractive, but deadly, fruits of Daphne mezereum .

Many of the species (e.g. Wikstroemia indica and Stellera chamaejasme ) have actual or potential uses in medicine and are poisonous if eaten, acting as violent purges (e.g. Daphne mezereum ), this toxicity often being related to the plants' containing phorbol esters which, as the name suggests, are also common in the spurge family Euphorbiaceae. [18]

Use as ornamental plants

The sweetly-scented and highly ornamental flowers of Daphne bholua, a Nepalese species used also in traditional paper-making. Daphne bholua (3307537340).jpg
The sweetly-scented and highly ornamental flowers of Daphne bholua , a Nepalese species used also in traditional paper-making.

Daphne is grown (despite the high toxicity of its attractive fruits) for its sweetly scented flowers. Species of Wikstroemia , Daphne , Phaleria , Dais , Pimelea and other genera are grown as ornamentals. [19] [4]

Related Research Articles

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<span class="mw-page-title-main">Caryophyllaceae</span> Family of flowering plants

Caryophyllaceae, commonly called the pink family or carnation family, is a family of flowering plants. It is included in the dicotyledon order Caryophyllales in the APG III system, alongside 33 other families, including Amaranthaceae, Cactaceae, and Polygonaceae. It is a large family, with 81 genera and about 2,625 known species.

<i>Daphne</i> (plant) Genus of flowering plants in the family Thymelaeaceae

Daphne is a genus of between 70 and 95 species of deciduous and evergreen shrubs in the family Thymelaeaceae, native to Asia, Europe and north Africa. They are noted for their scented flowers and often brightly coloured berries. Two species are used to make paper. Many species are grown in gardens as ornamental plants; the smaller species are often used in rock gardens. All parts of daphnes are poisonous, especially the berries.

Gonystylus is a southeast Asian genus of about 30 species of hardwood trees also known as ramin, melawis (Malay) and ramin telur (Sarawak).

<span class="mw-page-title-main">Theophrastoideae</span> Subfamily of flowering plant family Primulaceae

Theophrastoideae is a small subfamily of flowering plants in the family Primulaceae. It was formerly recognized as a separate family Theophrastaceae. As previously circumscribed, the family consisted of eight genera and 95 species of trees or shrubs, native to tropical regions of the Americas.

<i>Gnidia</i> Genus of flowering plants

Gnidia is a genus of flowering plants in the family Thymelaeaceae. It is distributed in Africa, Madagascar, Arabia, India, and Sri Lanka; more than half of all the species are endemic to South Africa. Gnidia was named for Knidos, an Ancient Greek city located in modern-day Turkey.

Solmsia is a genus containing one or two species of flowering plants belonging to the family Thymelaeaceae. It is endemic to New Caledonia. The genus was named to honor Hermann zu Solms-Laubach by Henri Ernest Baillon. It is related to Arnhemia, Deltaria, Gonystylus and Lethedon.

<i>Phaleria</i> Genus of flowering plants

Phaleria is flowering plant genus of about 20-25 species in the family Thymelaeaceae.

When the APG II system of plant classification was published in April 2003, fifteen genera and three families were placed incertae sedis in the angiosperms, and were listed in a section of the appendix entitled "Taxa of uncertain position".

Anthodon is a genus of flowering plants in the family Celastraceae. It comprises two species of large woody vines native to Central America and northern and Amazonian South America. They are scattered throughout most of the Neotropics, but are not common in any part of their range. They grow in wet forests from 100 m to 900 m in elevation. There is no known use of these vines by humans.

<i>Hydrostachys</i> Genus of flowering plants

Hydrostachys is a genus of about 22 species of flowering plants native to Madagascar and southern and central Africa. It is the only genus in the family Hydrostachyaceae. All species of Hydrostachys are aquatic, growing on rocks in fast-moving water. They have tuberous roots, usually pinnately compound leaves, and highly reduced flowers on dense spikes.

<span class="mw-page-title-main">Malveae</span> Tribe of flowering plants

Malveae is a tribe of flowering plants in the mallow family Malvaceae, subfamily Malvoideae. The tribe circumscribes approximately 70 genera and 1040 species and has the greatest species diversity out the three tribes that make up Malvoideae. The flowers of Malveae are five-merous with a characteristic staminal column, a trait found throughout Malvoideae. Although there are not many economically important species within Malveae, the tribe includes Althaea officinalis, otherwise known as the marsh-mallow.

<i>Edgeworthia</i> Genus of flowering plants

Edgeworthia is a genus of plants in the family Thymelaeaceae. When the genus was first described, it was published twice in the same year (1841), in two separate publications: Plantarum vascularium genera: secundum ordines naturales digesta eorumque differentiae et affinitates tabulis diagnostacis expositae; and Denkschriften der Regensburgischen Botanischen Gesellschaft. The genus was named in honour of Michael Pakenham Edgeworth, an Irish-born botanist and official in the Bengal Civil Service, then stationed in India, and for his half-sister, writer Maria Edgeworth.

Wikstroemia johnplewsii, common name Hiva Oa ohelo, is a plant species endemic to the island of Hiva Oa in the Marquesas Islands, French Polynesia. It is found at relatively high altitudes in the mountains, at elevations over 600 m. The only other member of the genus reported from the Marquesas is W. coriacea. Wikstroemia coriacea has narrower leaves and smaller inflorescences than. W. johnplewsii.

Durioneae is a tribe within the subfamily Helicteroideae of the plant family Malvaceae s.l. The tribe contains at least five genera, including Durio, the genus of tree species that produce Durian fruits.

Deltaria brachyblastophora is a species of shrubs in the Thymelaeaceae family. It is endemic to New Caledonia and the only species of the genus Deltaria. It is related to Arnhemia, Gonystylus, Lethedon and Solmsia.

Lethedon is a genus of shrubs in the Thymelaeaceae family from Australia and New Caledonia. It is related to Arnhemia, Deltaria, Gonystylus and Solmsia.

<i>Stellera</i> Genus of flowering plants

Stellera is a genus of flowering plant in the family Thymelaeaceae, with a single species Stellera chamaejasme found in mountainous regions of Central Asia, China, Siberia and South Asia. S. chamaejasme is a herbaceous perennial plant with heads of white, pink or yellow flowers, grown as an ornamental plant in rock gardens and alpine houses, but considered a weed playing a rôle in the desertification of grasslands in parts of its native range. Like many others of its family, it is a poisonous plant with medicinal and other useful properties.

Diarthron is a genus of flowering plant in the family Thymelaeaceae. The precise limits of the genus are uncertain. When broadly circumscribed to include Dendrostellera and Stelleropsis, it consists of annual and perennial herbaceous plants and small shrubs, with reddish, white or green flowers lacking petals, and is found in central and south-west Asia and south-east Europe.

<i>Dais</i> (plant) Genus of flowering plants

Dais is a genus of flowering plants in the family Thymelaeaceae. It is also part of the Gnidia subfamily, along with Gnidia, Drapetes, Kelleria, Pimelea, Struthiola, Lachnaea and Passerina, other genera of species). It is distributed between Tanzania to S. Africa, Madagascar. It is native to the countries of Eswatini, Lesotho, Madagascar, Malawi, Tanzania, Zimbabwe and it is also found within several Provinces of South Africa, such as Cape Provinces, Free State, KwaZulu-Natal and Northern Provinces.

References

  1. Zachary S. Rogers (2009 onwards). A World Checklist of Thymelaeaceae (version 1). Missouri Botanical Garden Website, St. Louis.
  2. Antoine Laurent de Jussieu Genera Plantarum, page 76. Herrisant & Barrois, Paris.
  3. Ernst Schmidt, Mervyn Lotter and Warren McCleland Trees and Shrubs of Mpumalanga and Kruger National Park (2002) , p. 448, at Google Books
  4. 1 2 3 4 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)
  5. Warren L. Wagner, Derral R. Herbst, and Sy H. Sohmer. Manual of the Flowering Plants of Hawaii, Revised Edition, 1999. Bishop Museum Press: Hololulu
  6. The Royal Horticultural Society Dictionary of Gardening ed. Chittenden, Fred J., 2nd edition, by Synge, Patrick M. Volume III : Je-Pt. Pub. Oxford at the Clarendon Press 1965. Reprinted 1984. ISBN   0-19-869106-8
  7. Peter F. Stevens (2001 onwards) Angiosperm Phylogeny Website In: Missouri Botanical Garden Website
  8. 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 Society129(4): 267-381
  9. 1 2 Michelle van der Bank, Michael F. Fay, and Mark W. Chase (2002). "Molecular Phylogenetics of Thymelaeaceae with particular reference to African and Australian genera". Taxon51(2):329-339.
  10. 1 2 3 4 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)
  11. David Galicia-Herbada (2006). "Origin and diversification of Thymelaea(Thymelaeaceae): inferences from a phylogenetic study based on ITS (rDNA) sequences". Plant Systematics and Evolution257(3-4):159-187.
  12. Rogers, Z.S. (2009). "A World Checklist of Thymelaeaceae (version 1)". Missouri Botanical Garden, St. Louis. Retrieved 26 November 2021.
  13. Hutchinson,John. The Families of Flowering Plants, Third Edition (1973). Oxford University Press: London.
  14. Horn,J.W., (2004). "The morphology and relationships of the Sphaerosepalaceae(Malvales)". Botanical Journal of the Linnean Society144(1):1-40
  15. 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).
  16. Vernon H. Heywood, Richard K. Brummitt, Alastair Culham, and Ole Seberg. Flowering Plant Families of the World. Firefly Books: Ontario, Canada (2007)
  17. 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).
  18. Goel, G; Makkar, H. P.; Francis, G; Becker, K (2007). "Phorbol esters: Structure, biological activity, and toxicity in animals". International Journal of Toxicology. 26 (4): 279–88. CiteSeerX   10.1.1.320.6537 . doi:10.1080/10915810701464641. PMID   17661218. S2CID   11550625.
  19. George W. Staples and Derral R. Herbst. 2005. "A Tropical Garden Flora". Bishop Museum Press: Honolulu. ISBN   978-1-58178-039-0.