| Phyllanthaceae | |
|---|---|
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| Breynia disticha | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Malpighiales |
| Family: | Phyllanthaceae Martynov[2] |
| Tribes | |
See text | |
Phyllanthaceae is afamily offlowering plants in theeudicotorderMalpighiales. It is most closely related to the familyPicrodendraceae.[3]
The Phyllanthaceae are most numerous in thetropics, with many in thesouth temperate zone, and a few ranging as far north as the middle of thenorth temperate zone.[4]
Some species ofAndrachne,Antidesma,Margaritaria, andPhyllanthus are in cultivation.[5] A few species ofAntidesma,Baccaurea,Phyllanthus, andUapaca bear edible fruit.[4]
Phyllanthaceae comprises about 2000 species.[6][7] Depending on the author, these are grouped into 54 to 60genera. Some of the genera are poorly defined, and the number of genera in the family is likely to change as the classification is further refined. The genusPhyllanthus, one of the largest genera of flowering plants with over 1200 species, has more than half of the species in the family.[8]
Some of the genera have recently been sunk into others, while other genera have recently been divided.[9][10] The largest genera and the approximate number of species in each are:Phyllanthus (1270),Cleistanthus (140),Antidesma (100),Aporosa (90),Uapaca (60),Baccaurea (50), andBridelia (50).[11]
Since Phyllanthaceae was revised in 2006, one paper has removedHeterosavia fromSavia.[12] Another has separatedNotoleptopus fromLeptopus, and segregatedPseudophyllanthus andPhyllanthopsis fromAndrachne. Also,Oreoporanthera has been subsumed intoPoranthera, whileZimmermannia andZimmermanniopsis have been sunk intoMeineckia.[13] The large genusCleistanthus is known to bepolyphyletic, but further studies will be needed before it can be revised.[6]
The description here is from Hoffmann,[4][14] except for a few additions from Webster[15] and Hutchinson[16] where cited. Phyllanthaceae is an unusually diverse family for its moderate size. It can be recognized only by a combination of characters because there are a few exceptions to almost everything that is generally true of the family. It is most notable for having twoovules in eachlocule of theovary, a trait that clearly distinguishes it fromEuphorbiaceae.
The Phyllanthaceae are nearly alltrees,shrubs, orherbs. A few areclimbers, orsucculents, and one species,Phyllanthus fluitans, isaquatic. Unlike many of theEuphorbiaceae, none haslatex, and only a very few produce aresinous exudate. Anyhairs, if present, are almost always simple. Rarely are they branched or scale-like. Thorns and other armament are rare.
Stipules are produced with eachleaf, but in some, these fall before the leaf is fully mature. Leaves are present, except for a few species ofPhyllanthus that have flattened, leaflike stems calledcladodes that bear flowers along their edges. The leaves arecompound inBischofia, but otherwise simple and usuallyalternate. Rarely are theyopposite, infascicles, or inwhorls around the stem. The leaf margin is almost alwaysentire, rarely toothed. Apetiole is nearly always present, often with apulvinus at its base.
Theinflorescences are usually in theaxils of leaves, rarely below the leaves or at the ends of stems. InUapaca, the flowers are in apseudanthium, a tight bundle of flowers that resembles a single flower.
Except for four species ofAporosa, the flowers are unisexual, the plants being eithermonoecious ordioecious. The flowers areactinomorphic in form. Detailed illustrations have been published for some of these.[13]
Thesepals are three to eight in number, usually free from each other.Petals may be absent or present. If present, there are usually four to six, and their color is yellow to green, or rarely, pink or maroon.
Anectary disk is often present. It may be in the form of a ring, or divided into segments. Thestamens are three to ten in number, or rarely more, free or variously fused.
Theovary issuperior. The number oflocules in the ovary is highly variable, usually from two to five, but sometimes as many as fifteen. Theplacentation isapical, with a pair ofovules hanging by theirfunicles from the top of each locule.[16] Often, only one of the ovules will develop into aseed. A single, massiveobturator may cover themicropyles of both ovules, or each ovule may have its own thin obturator. Themegagametophyte is of thePolygonum type.[15] Thestyle is usually 2-lobed orbifid, sometimesentire, or rarely multifid.
The fruit is aschizocarp,drupe, orberry. In some, theschizocarp breaks up explosively.
The name "Phyllanthaceae" was firstvalidly published byIvan Ivanovich Martynov in 1820 in aRussian book entitledTekhno-botanico Slovar. A proposal to conserve this name was published in 2007.[17]
Martynov's name was rarely used in the 180 years after he published it. During that time, the plants that are now in Phyllanthaceae were placed in the large and heterogeneous familyEuphorbiaceae. Themonophyly of Euphorbiaceae had long been held in doubt by some, but the first strong evidence of itspolyphyly came in 1993 with the firstmaximum parsimony analysis ofDNA sequences of thegenerbcL from a large number ofseed plants.[18] Since the 1993 study, all subsequentphylogenetic analyses have shown that the old concept of Euphorbiaceae consisted of severallineages that did not together form aclade in the orderMalpighiales. Euphorbiaceae is now defined as a much smaller family than it had been in the twentieth century.[19][20]Pandaceae, Phyllanthaceae,Picrodendraceae,Putranjivaceae,Peraceae, andCentroplacaceae have been removed from it.[11]
The obsolete, older concept of Euphorbiaceae, known as Euphorbiaceaesensu lato, is sometimes still used for continuity and convenience.[21] It was the subject of a book and two papers which stood as the standard works on Phyllanthaceae until that family was revised by Hoffmann and co-authors in 2006.[15][22][23]
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In the past, the generaCentroplacus,Paradrypetes, andPhyllanoa had been placed in Phyllanthaceae, but these are now excluded from the family.Centroplacus is now in the familyCentroplacaceae.[11]Paradrypetes is inRhizophoraceae.[3]Phyllanoa is known only from a single specimen. In 1996, this was examined and found to be a species ofRinorea (Violaceae).[24]
The family Phyllanthaceae is divided into two subfamilies: Antidesmatoideae and Phyllanthoideae. Antidesmatoideae is divided into six tribes and Phyllanthoideae is divided into four. The tribe Antidesmateae of Antidesmatoideae, and the tribes Bridelieae and Wielandieae of Phyllanthoideae are further divided into subtribes. The following classification table is from the 2006 revision of Phyllanthaceae.
Incertae sedis:Chonocentrum
SubfamilyAntidesmatoideae 6 tribes
SubfamilyPhyllanthoideae 4 tribes
Plants of the World Online currently accepts 60 genera.[25]
A 2006 revision of Phyllanthaceae by Petra Hoffmann and co-authors recognized 54 genera. In their treatment,Blotia andPetalodiscus were sunk intoWielandia andRicheriella intoFlueggea.Breynia,Glochidion,Reverchonia, andSauropus were recommended to be subsumed intoPhyllanthus, but many new species combinations must be published to effect this change. Genera previously considered as the tribeDrypeteae are now placed in the separate familyPutranjivaceae.[14] Plants of the World Online still acceptsBreynia andGlochidion,[25] and subsumesSauropus intoBreynia.[26]
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The revision of Phyllanthaceae by Hoffmann and co-authors was based on twomolecular phylogenetic studies that were published in 2005.[6][7] Since the revision, phylogenetic studies have been done on some of the tribes.[8][27]
The phylogenetic tree shown below is based on the results of several studies.[8][12][13][14] Fifty-one genera are represented.Chonocentrum(Phyllanthaceae,incertae sedis), and three members of the tribe Scepeae (Ashtonia,Distichirrhops, andNothobaccaurea) have not yet been sampled for DNA.Chonocentrum is known from only a single specimen collected in the 1850s.[24]
In the phylogeny shown below, statistical support for the clades was measured bybootstrap percentage. All branches shown below havemaximum parsimony bootstrap support of at least 70%.
| Antidesmatoideae |
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| Phyllanthoideae |
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