| Boraginales | |
|---|---|
 | |
| Echium vulgare | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Asterids |
| Clade: | Lamiids |
| Order: | Boraginales Juss. exBercht. & J.Presl |
| Families | |
Boraginales is anorder of flowering plants in theasterid clade, with a total of about 125 genera and 2,700 species. Different taxonomic treatments either include only a single family, theBoraginaceae, or divide it into up to eleven families. Its herbs, shrubs, trees andlianas (vines) have a worldwide distribution.
The classification of plants now known as Boraginales dates to theGenera plantarum (1789) whenAntoine Laurent de Jussieu named a group of plants Boragineae, to include the genusBorago, now thetype genus. However, since the first valid description was byFriedrich von Berchtold andJan Svatopluk Presl (1820),[2] thebotanical authority is given as Juss.ex Bercht. & J.Presl,ex (Latin, meaning 'out of', 'from') indicating the prior authority of Jussieu. Lindley (1853) changed the name to the modern Boraginaceae.[3]
Jussieu divided the Boragineae into five groups.[4][5] Since thenBoraginaceae has been treated either as a large family with several subfamilies, or as a smaller family with several closely related families.[6] The family had been included in a number of higher order taxa, but in 1926Hutchinson erected a new order, Boraginales, to include the Boraginaceae.
Although Boraginales was included in a number of taxonomicclassifications includingDahlgren (1980),Takhtajan (1997) andKubitzki (2016)[7] as anorder, it was not recognized in either of two majorsystems, theCronquist system[8] and theAPG system. In the Cronquist system, Boraginaceae (includingCordiaceae,Ehretiaceae, andHeliotropiaceae) andLennoaceae were placed in the orderLamiales, while the relatedHydrophyllaceae was placed inSolanales.
The APG system took a broad view of Boraginaceae (Boraginaceaes.l.), including within it the traditionally recognized familiesHydrophyllaceae andLennoaceae based on recentmolecular phylogenies that show that Boraginaceae, as traditionally defined, isparaphyletic over these two families.APG III included Boraginaceae in theEuasterid I (lamiid)clade but this family was otherwiseunplaced; its precise relationship to other families in the Euasterid I group remained unclear. In aphylogeneticstudy ofDNA sequences of selectedgenes, Boraginales was resolved assister to Lamiales sensu APG, but that result had only 65%maximum likelihoodbootstrap support.[9]
In the 2016APG IV system Boraginales is an order with only one family Boraginaceae, which includes the former familyCodonaceae. At the time of the APG IV consensus there was insufficient support to further divide thismonophyletic group further.[10] (For a complete discussion of the history of the taxonomy of Boraginales, seeBWG (2016))
Following the publication of APG IV, a collaborative group along similar lines to the APG, the Boraginales Working Group (BWG),[1] has published an alternative taxonomy based on thephylogenetic relationships within the Boraginaceaes.l.[6][11] This classification split the order into eleven families, including: Boraginaceaes.s. or s.str.,Cordiaceae,Ehretiaceae,Heliotropiaceae, and Hydrophyllaceae. A number of these weremonogeneric. Boraginaceaes.s. is hard tocharacterizemorphologically if it includes thegeneraCodon andWellstedia.[12]Codon was long regarded as an unusual member ofHydrophyllaceae, but in 1998, amolecular phylogeneticstudy showed that it is closer to Boraginaceae,[13] and bothCodon andWellstedia have been allocated to their own families,Codonaceae andWellstediaceae.[11][14]
TheachlorophyllousholoparasitesLennoa andPholisma were once regarded as a family,Lennoaceae, but it is now known that they form aclade that is nested within Ehretiaceae.[15] Some studies indicated that Hydrophyllaceae was paraphyletic if thetribe Nameae was included within it,[9] and the BWG recognizes the segregate familyNamaceae.[11]
The inclusion of the genusHoplestigma in Boraginales was occasionally doubted until it was stronglyconfirmed in acladistic study in 2014.[8]Hoplestigma is asister taxon of Cordiaceae, and is recognized in the segregate familyHoplestigmataceae.[11]
The BWG classification of the Boraginales is based on the cladogram:[11]
| Boraginales |
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Hydrolea was thought to belong in Hydrophyllaceae for more than a century after it was placed there byAsa Gray, but it is now known to belong in the orderSolanales as sister toSphenoclea.[9]
Pteleocarpa was long regarded as ananomaly, and was usually placed in Boraginales, but with considerable doubt. Themolecularevidence strongly supports it as sister toGelsemiaceae,[9] and that family has been expanded to include it.[16]
