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. 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. [3] 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. [4] 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. [3]

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. [5]

Classification

The Thymelaeaceae are in the order Malvales. [6] Except for a sister relationship with Tepuianthaceae, little is known for sure about their relationships with the other families in the order. [7]

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. [8] 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. [3] [9] 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, [10] 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) [8] 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) [9] recognized 45 genera, excluding Tepuianthus from the family, sinking Atemnosiphon and Englerodaphne into Gnidia, Eriosolena into Daphne, and Thecanthes into Pimelea. [9] 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). [9]

As of December 2014, 50 genera are accepted by the World Checklist of Thymelaceae: [11]

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. [12] 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. [13] Stevens includes Tepuianthus, but Kubitzki treats Tepuianthaceae as a separate family. [14]

Distribution

The family is more diverse in the Southern Hemisphere than in the Northern, with major concentrations of species in Africa and Australia. [15] The genera are overwhelmingly African. [16]

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 Thymelaea , Edgeworthia 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. [17]

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. [18] [3]

Related Research Articles

Lamiaceae Family of flowering plants that includes sage and mint

The Lamiaceae or Labiatae are a family of flowering plants commonly known as the mint or deadnettle or sage family. Many of the plants are aromatic in all parts and include widely used culinary herbs like basil, mentha, rosemary, sage, savory, marjoram, oregano, hyssop, thyme, lavender, and perilla. Some species are shrubs, trees, or, rarely, vines. Many members of the family are widely cultivated, not only for their aromatic qualities, but also their ease of cultivation, since they are readily propagated by stem cuttings. Besides those grown for their edible leaves, some are grown for decorative foliage. Others are grown for seed, such as Salvia hispanica (chia), or for their edible tubers, such as Plectranthus edulis, Plectranthus esculentus, Plectranthus rotundifolius, and Stachys affinis.

Zingiberaceae family of plants

Zingiberaceae or the ginger family is a family of flowering plants made up of about 50 genera with a total of about 1600 known species of aromatic perennial herbs with creeping horizontal or tuberous rhizomes distributed throughout tropical Africa, Asia, and the Americas.

Malvaceae Family of flowering plants

Malvaceae, or the mallows, is a family of flowering plants estimated to contain 244 genera with 4225 known species. Well-known members of economic importance include okra, cotton, cacao and durian. There are also some genera containing familiar ornamentals, such as Alcea (hollyhock), Malva (mallow) and Lavatera, as well as Tilia. The largest genera in terms of number of species include Hibiscus, Sterculia, Dombeya, Pavonia and Sida.

Bombacaceae family of plants

Bombacaceae were long recognised as a family of flowering plants or Angiospermae. The family name was based on the type genus Bombax. As is true for many botanical names, circumscription and status of the taxon has varied with taxonomic point of view, and currently the preference is to transfer most of the erstwhile family Bombacaceae to the subfamily Bombacoideae within the family Malvaceae in the order Malvales. The rest of the family were transferred to other taxa, notably the new family Durionaceae. Irrespective of current taxonomic status, many of the species originally included in the Bombacaceae are of considerable ecological, historical, horticultural, and economic importance, such as balsa, kapok, baobab and durian.

<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.

Brodiaeoideae subfamily of plants

Brodiaeoideae are a monocot subfamily of flowering plants in the family Asparagaceae, order Asparagales. They have been treated as a separate family, Themidaceae. They are native to Central America and western North America, from British Columbia to Guatemala. The name of the subfamily is based on the type genus Brodiaea.

Phyllanthaceae Family of flowering plants

Phyllanthaceae is a family of flowering plants in the eudicot order Malpighiales. It is most closely related to the family Picrodendraceae.

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

Parnassiaceae family of plants

Parnassiaceae Gray were a family of flowering plants in the eudicot order Celastrales. The family is not recognized in the APG III system of plant classification. When that system was published in 2009, Parnassiaceae were treated as subfamily Parnassioideae of an expanded family Celastraceae.

Huerteales order of plants

Huerteales is the botanical name for an order of flowering plants. It is one of the 17 orders that make up the large eudicot group known as the rosids in the APG III system of plant classification. Within the rosids, it is one of the orders in Malvidae, a group formerly known as eurosids II and now known informally as the malvids. This is true whether Malvidae is circumscribed broadly to include eight orders as in APG III, or more narrowly to include only four orders. Huerteales consists of four small families, Petenaeaceae, Gerrardinaceae, Tapisciaceae, and Dipentodontaceae.

Capparaceae Family of caper flowering plants

The Capparaceae, commonly known as the caper family, are a family of plants in the order Brassicales. As currently circumscribed, the family contains 33 genera and about 700 species. The largest genera are Capparis, Maerua, Boscia and Cadaba.

<i>Vitex</i> Genus of flowering plants in the sage family Lamiaceae

Vitex is a genus of flowering plants in the family Lamiaceae. It has about 250 species. Common names include "chaste tree" or "chastetree", traditionally referring to V. agnus-castus but often applied to other species as well.

<i>Gnidia</i> genus of 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.

Commelinoideae Subfamily of flowering plants

Commelinoideae is a subfamily of monocotyledonous flowering plants in the dayflower family (Commelinaceae). The Commelinoideae is one of two subfamilies within the Commelinaceae and includes 39 genera and all but 12 of the family's several hundred known species. The subfamily is further broken down into two tribes, the Tradescantieae, which includes 26 genera and about 300 species, and the Commelineae, which contains 13 genera and about 350 species.

<i>Edgeworthia</i> genus of 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.

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 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.

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. 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)
  4. Warren L. Wagner, Derral R. Herbst, and Sy H. Sohmer. Manual of the Flowering Plants of Hawaii, Revised Edition, 1999. Bishop Museum Press: Hololulu
  5. 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
  6. Peter F. Stevens (2001 onwards) Angiosperm Phylogeny Website In: Missouri Botanical Garden Website
  7. 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
  8. 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.
  9. 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)
  10. 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.
  11. Rogers, Z.S. (2009). "A World Checklist of Thymelaeaceae (version 1)". Missouri Botanical Garden, St. Louis.Missing or empty |url= (help)
  12. Hutchinson,John. The Families of Flowering Plants, Third Edition (1973). Oxford University Press: London.
  13. Horn,J.W., (2004). "The morphology and relationships of the Sphaerosepalaceae(Malvales)". Botanical Journal of the Linnean Society144(1):1-40
  14. 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).
  15. Vernon H. Heywood, Richard K. Brummitt, Alastair Culham, and Ole Seberg. Flowering Plant Families of the World. Firefly Books: Ontario, Canada (2007)
  16. 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).
  17. 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.
  18. George W. Staples and Derral R. Herbst. 2005. "A Tropical Garden Flora". Bishop Museum Press: Honolulu. ISBN   978-1-58178-039-0.