| Ochnaceae | |
|---|---|
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| Sauvagesia erecta from southern Brazil | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Malpighiales |
| Family: | Ochnaceae DC.[2] |
| Genera | |
Seetext | |
Ochnaceae is afamily offlowering plants in theorderMalpighiales.[3] In theAPG III system ofclassification of flowering plants, Ochnaceae is defined broadly, to include about 550species,[4] and encompasses what sometaxonomists have treated as theseparate familiesMedusagynaceae andQuiinaceae.[2] In aphylogeneticstudy that waspublished in 2014, Ochnaceae was recognized in the broadsense,[5] but twoworks published after APG III have accepted the small families Medusagynaceae and Quiinaceae.[4][6] These have not been accepted by APG IV (2016).
In this article, "Ochnaceae" will refer to the largercircumscription of the family, which is otherwise known as Ochnaceaesensu lato or as the ochnoids.[7] In this sense the family includes 32 genera with about 550 species.[8]
Ochnaceae, defined broadly or narrowly, is pantropical indistribution, with a few speciescultivated outside of thisrange. Ochnaceae is mostdiverse in theneotropics, with a secondcenter of diversity intropical Africa.[5] It consists mostly of shrubs and small trees, and, inSauvagesia, a fewherbaceous species. Many are treelets, with a single, erecttrunk, but low in height. The Ochnaceae are notable for their unusual leaves. These are usually shiny, with closely spaced, parallel veins, toothed margins, and conspicuousstipules. Most of the species arebuzz pollinated.[9] In eight of the genera intribe Sauvagesieae, the flower changesform afteropening, by continuedgrowth oftissue within the flower.[5]
A few species ofOchna arecultivated asornamentals.[10]Ochna thomasiana is probably the most commonlyplanted, but it is oftenmisidentified in the horticulturalliterature.[11]
The leaves ofCespedesia are sometimes to 1 m (3.3 ft) inlength and are used forroofing.[12] Anherbal tea is made from the pantropicalweedSauvagesia erecta.
In itsevolution, Ochnaceae has been unusual, in "reverting" tocharacter states that are regarded asancestral orprimitive. For example, anactinomorphicfloral symmetry has appeared twice in thesubfamily Ochnoideae. Also, twoclades of Ochnaceae, one in Ochnoideae and another in Quiinoideae have aderived condition very close toapocarpy. The complete separation of thecarpels (apocarpy) is thought to be theancestral state forangiosperms.[13]
Fossils attributed to Ochnaceae are known from the earlyEocene ofMississippi.[14] Theage of the family is very roughlyestimated at 100 million years.[15]
A great manygenus names have been published in Ochnaceae.[16] In ataxonomic revision of Ochnaceae, as three families, in 2014, only 32 of these genera were accepted; one in Medusagynaceae, four in Quiinaceae, and 27 in Ochnaceaes.s.[4] In that same year, a 33rd genus,Neckia, was reestablished in order to preserve themonophyly of another genus,Sauvagesia.[5]
The largest genera in Ochnaceae are:Ouratea (200 species),Ochna (85),Campylospermum (65),Sauvagesia (39), andQuiina (34).[4] None of the larger genera has been the subject of aphylogenetic analysis ofDNA sequences of selectedgenes. In one study of the subfamily Quiinoideae, based on thetrn L-Fintergenic spacer, only nine species weresampled from this subfamily.[17]
The following list of 36 genera consists ofNeckia, which was resurrected in 2014,[5]Indovethia,[18]Polythecanthum andSinia,[19] plus the 32 genera that weredescribed in the most recent revision of Ochnaceae.[4][20][21] The classification is from Schneideret alii (2014).[5]
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The followingdescription isexcerpted from the descriptions of Medusagynaceae, Quiinaceae, and Ochnaceaes.s. inThe Families and Genera of Vascular Plants,[4][20][21] with some information from other sources, as indicated.
Mostlyshrubs and smalltrees, plus a few trees of moderate size, and inSauvagesia, a fewherbs.
Leavessimple, exceptpinnatelycompound inKrukoviella,[3] and in Quiinoideae, often pinnatelylobed or compound onjuvenile plants. Pinnate leaves are typical ofRhytidanthera.[5] The leaves are oftencoriaceous and conspicuouslyserrate.Stipules present, exceptMedusagyne.
Venation oftenscalariform (ladder-like) in appearance, with parallel and closely spacedsecondary andtertiaryveins.Petiolesabsent or short, sometimes resembling apulvinus.[3]
Unisexualflowers are common inMedusagyne and in Quiinoideae (exceptFroesia), but restricted to a clade of three genera in Ochnoideae. Unisexual flowers are found inSchuurmansia,Schuurmansiella, andEuthemis.[5] The flowers are always unisexual inSchuurmansiella.[4]
Inpolygamous species, flowers have been assessed asbisexual on the basis ofmorphology only.[17]Pollen produced by apparentlyhermaphroditic flowers has, in a few cases, been found to beinaperturate, rendering the flowerfunctionallyfemale.
Sepals 3 to 5, often unequal, sometimesaccrescent.
Petals 4 or 5, or rarely 3, 6, 7, or 8, oftencontort,free orfuzed at base only, sometimes reflexed over the sepals.
Fertilestamens 5 to 10 ornumerous, rarely one.Filaments sometimespersistent, sometimes narrowed near theanthers.
Anthersbasifixed or slightlydorsifixed, usuallydehiscing by one or twoapical or subapical pores, sometimeslatrorsely bylongitudinal slits. InMedusagyne and Quiinoideae, an enlargedseptum separates thethecae.
Staminodes often present, free orconnate, sometimes petaloid, sometimes enveloping the fertile stamens.
Nectar notproduced. Flowers usuallybuzz-pollinated.
Ovarysuperior, longitudinally ribbed inMedusagyne and Quiinoideae; unribbed in Ochnoideae.Carpels completely fused or nearly separate; 2-15, or up to 25 inMedusagyne.Style apical orgynobasic.
Fruit sometimeswinged; rarely anut ordrupe, oftenberry-like; usually asepticidalcapsule, or else the ovary separating to form blackishdrupelets on a usually reddish,accrescentreceptacle.
Seedsalbuminous orexalbuminous, winged or not. Theseed coat often includes a layer ofcristarque cells. These aresclereids, each containingcalcium oxalatecrystals in the form of adruse.
Until near the end of the 20th century, Ochnaceae was regarded as a rather odd family, difficult to place with a high degree of certainty. Even into the 21st century, someauthors treated the genusStrasburgeria as theclosest relative of Ochnaceae, and some even placed it within the family.[22] In theAPG III system,Strasburgeria is grouped withIxerba to form the familyStrasburgeriaceae in therosid orderCrossosomatales.[23]
More rarely, the genusDiegodendron was thought to be close toStrasburgeria and Ochnaceae.Molecular phylogenetic studies havestrongly supported the inclusion ofDiegodendron in the rosid orderMalvales, and it is sometimes treated as amonospecific family therein.[24] Otherwise, it has been placed inBixaceae, though there is reason to suspect that it might be closer toSphaerosepalaceae.[23]
All of the genera mentioned above, as well as Ochnaceae, were long regarded asanamaloustaxa of uncertainaffinity. All had been placed, at one time or another, with Ochnaceae, nearTheaceae, a family now included in thebasalasterid orderEricales.[23]
In 2012, an analysis ofchloroplastDNA resolved Ochnaceae assister to agroup of five families known as theclusioids.[6] This result had only weakbootstrap support. The clusioids were once regarded as a group of four families,[25] butClusiaceae was divided in 2009[7] and the nameCalophyllaceae was resurrected for one of the resulting segregates.[2][26]
There are only a fewmorphologicalcharacters thatunite the clusioids with Ochnaceae. The petalaestivation is oftencontort in the clusioids, and usually so in Ochnaceae. In both groups, the flowers usually bearnumerousstamens, and in theovary, theplacentation is mostlyaxile. In theovules, thenucellus is often thin, and the outerintegument is usually thicker than the inner.[27]
Ochnaceae is divided into three subfamilies: Medusagynoideae, Quiinoideae, and Ochnoideae.[5]
A molecular phylogenetic study resolved Medusagynoideae and Quiinoideae assister subfamilies, but this result had only weakstatistical support.[6] In both subfamilies, the flowers arepolystemonous. Except for the genusFroesia, many or all of the flowers areunisexual. Theanthers contain a massiveseptum between thethecae thatpersists after antherdehiscence. Thestyles radiate outward from the ovary. Atanthesis, the ovary is sculpted with longitudinal ribs.[28]
Medusagynoideae consists of a single species,Medusagyne oppositifolia. It isendemic to theisland ofMahé in theSeychelles.[29]
Quiinoideae comprises about 48 species in four genera:Froesia,Quiina,Touroulia, andLacunaria. It is restricted totropicalAmerica.[30]Froesia is distinct from the other three genera. Its flowers are always bisexual, and the fruit consists of three structures that resemblefollicles, except that they are not quite entirely separate from each other.
The subfamily Ochnoideae was revised in 2014 as Ochnaceaesensu stricto.[4] In that treatment, 27 genera were described. An additional genus,Neckia, was resurrected in that same year, based on the results of a molecular phylogenetic study.[5] Amaral and Bittrich (2014) divided Ochnoideae into three tribes: Luxemburgieae, Sauvagesieae, and Ochneae. The genusTestulea was included in the tribe Sauvagesieae. No subtribes were recognized.
In 2014, a second reclassification of Ochnoideae was published, based oncladistic analysis ofDNA sequences. In that paper, Schneideret alii divided Ochnoideae into four tribes: Testuleeae, Luxemburgieae, Sauvagesieae, and Ochneae. Their circumscription of the tribes was the same as that of Amaral and Bittrich (2014), except thatTestulea was removed from Sauvagesieae into its own tribe, Testuleeae. Inclusion ofTestulea in Sauvagesieae renders that tribeparaphyletic over Luxemburgieae.
Testulea consists of a single species,Testulea gabonensis, that is endemic toGabon. It is unique in Ochnoideae in that its leaves have abrochidodromous pattern ofvenation and its flowers aretetramerous. In addition, only one of the stamens isfertile. The others aremodified intostaminodes andunited into a column for up to2⁄3 of their length.
The tribe Luxemburgieae consists of two genera:Philacra andLuxemburgia.Philacra is native toVenezuela and northernBrazil.Luxemburgia is from Brazil.
The tribe Sauvagesieae is pantropical in distribution, and consists of 16 genera, most of them small. The largest, by far, isSauvagesia, with 38 species, 35 of which are restricted to theneotropics.[12]Sauvagesia is heterogeneous, and might be paraphyletic, even withNeckia removed from it. Relationships in the tribe Sauvagesieae are not well understood, and for this reason, it has not been divided intosubtribes.[5]
The tribe Ochneae is found in most of the tropics, but is most abundant inAfrica and tropical America. It is distinguished from the rest of Ochnoideae by the absorption of theendosperm before the seed reachesmaturity. Its nine genera belong to three subtribes: Lophirinae, Elvasiinae, and Ochninae.[5]
The subtribe Lophirinae consists of a single genus,Lophira. It has two species, both confined to tropical Africa. It produces an unusual fruit, in which two of the sepals become greatlyenlarged and formwings that facilitateseed distribution bywind.
The subtribe Elvasiinae consists of two genera,Perissocarpa andElvasia, both confined to theAmerican tropics.Perissocarpa has never been sampled for a molecular phylogenetic study.
The subtribe Ochninae consists of six genera:Campylospermum, Ouratea, Idertia, Brackenridgea, Rhabdophyllum, andOchna. The largest of these,Ouratea, is confined to theNew World and contains all of the New World species in Ochninae. All of the genera in Ochneae appear to bemonophyletic, as defined by Amaral and Bittrich (2014), but in one molecular phylogenetic study,Ouratea andOchna received only weakbootstrap support in themaximum likelihood analysis.[5]Idertia andBrackenridgea are probably sister genera, but no other relationships have been resolved among the genera of Ochninae.
Thephylogenetic tree below is adapted from the one that was published in 2014.[5] Weakly supported nodes are collapsed to formpolytomies.Maximum likelihoodbootstrap support is > 75%, except where indicated.Perissocarpa andIndosinia have not been sampled forDNA. Their placement on the phylogenetic tree is based onanatomy andmorphology only.
| MEDUSAGYNOIDEAE QUIINOIDEAE OCHNOIDEAE |
Theevolution of Ochnaceae has been unusual in that it has included two completereversions to anactinomorphicfloral symmetry and two nearly complete reversions toapocarpy, a condition in which thecarpels are entirely separate. Actinomorphy and apocarpy are believed to be "primitive"character states inangiosperms.[31] Secondary apocarpy is especially rare and hasarisen most notably inRosaceae,Apocynaceae,Sapindales, andMalvales.[13]
The flowers are actinomorphic inMedusagyne and Quiinoideae, but in Ochnoideae,zygomorphy is theancestral condition. InTestulea,Philacra, andLuxemburgia, the flowersdevelop zygomorphically in thebud. But in the fourbasalclades of Sauvagesieae, comprising the generaBlastemanthus, Godoya, Rhytidanthera, Krukoviella, Cespedesia, Fleurydora, Poecilandra, andWallacea, the flowersdevelop actinomorphically in the bud, then become zygomorphic afteropening bygrowth of certain parts of the flower. Such late zygomorphy is very rare in flowering plants. In the remaining, fifth clade of Sauvagesieae, comprising the generaNeckia, Schuurmansia, Schuurmansiella, Euthemis, Tyleria, Adenarake, Indosinia, andSauvagesia, the flowers remain actinomorphic after anthesis. In the tribe Ochneae, all of the species have actinomorphic flowers.
In the subtribe Ochninae, and in the genusFroesia, the components of the ovary (carpels) are very shortlyunited at the base. Otherwise, the ovary in Ochnaceae issyncarpous, consisting of carpels that are completely fuzed.
InMedusagyne and Quiinoideae, many of the flowers are unisexual, except inFroesia, where they are strictlyhermaphrodite. In Ochnoideae, unisexual flowers are limited to a clade consisting ofSchuurmansia,Schuurmansiella, andEuthemis.[5]
InMedusagyne and Quiinoideae, as in most angiosperms, theanthers open by longitudinal slits. In Ochnoideeae, the antherdehiscence isancestrallyporicidal, with several reversions to longitudinal slits.Testulea,Philacra, andLuxemburgia have anthers that open byapical pores. So do the three most basal clades of Sauvagesieae, namelyBlastemanthus,Fleurydora, and a clade of four genera that have five carpels and many ovules per carpel (Godoya, Rhytidanthera, Krukoviella, andCespedesia).Poecilandra has poricidal anther dehiscence, but in itssister genus,Wallacea, the anthers open by longitudinal slits.
In the rest of Sauvagesieae, anther dehiscence is various. InSchuurmansia,Schuurmansiella, andAdenarake, the anther dehiscence is apicallylongicidal. This means that the longitudinal slit is short, and does not extend far from the apical end of the anther. In some species ofSauvagesia, the anthers split lengthwise, but the entireandroecium is wrapped in petaloidstaminodes, so that thepollen can escape from only the apex of the anther. This is known as a poricidal system because it functions as if the anthers were truly poricidal.
In the tribe Ochneae, anther dehiscence by longitudinal slits is restricted toBrackenridgea and a few species ofOchna.
Testulea is peculiar in having only onefertilestamen. Its anther opens by an apical pore. The other stamens aremodified intosterile staminodes that are fuzed into a column for up to2⁄3 of their length.
In the generaFroesia andQuiina, and in the tribe Ochneae, theendosperm is completely absorbed early in seed development. It is not clear whether the presence or absence of endosperm is the ancestral state in Ochnaceae. For a long time, the subfamily Ochnoideae was divided into two groups based on this character alone. In such a classification, the group containing endosperm would beparaphyletic over Ochneae because it would containTestulea,Philacra, andLuxemburgia.
The number ofovules percarpel varies widely in Ochnaceae.Medusagyne and Quiinoideae have two ovules per carpel. InTestulea and in a clade of four genera in Sauvagesieae (Godoya, Rhytidanthera, Krukoviella, andCespedesia), the number of ovules is 100 to 200 per carpel. For the remainder of Sauvagesieae, exceptEuthemis, and forPhilacra andLuxemburgia, the number of ovules per carpel ranges from four to 50.Euthemis has two ovules per carpel.
In Ochneae,Lophira has 4 to 50 ovules per carpel. In the subtribes Elvasiinae and Ochninae, the number of ovules per carpel is one.
The family Ochnaceae was erected byAugustin Pyramus de Candolle in 1811.[32][33] At that time, he describedElvasia, a new genus in the family, and he included three others:Ochna,Walkera, andGomphia.[34]Walkera was described byJohann Christian Daniel von Schreber in 1789, but is no longer recognized. Itstype species was described asGomphia serrata byAndrias Kanis in 1968,[35] but it is now placed in the genusCampylospermum.[citation needed]Gomphia has long been a source of confusion[36] and it was not recognized in the most recent revision of Ochnaceae.[4]
Godoya andSauvagesia were known in 1811, when de Candolle erected the family Ochnaceae, but he placed them in other families. In hisProdromus, he placedGodoya in the family that would later be known asClusiaceae.[37] He regardedLauradia (Lavradia) as separate fromSauvagesia, and placed both of them inViolaceae. He added the genusCastela to Ochnaceae, but it is now part ofSimaroubaceae.[38] De Candolle believed that Simaroubaceae was closely related to Ochnaceae, but it is now placed in theorderSapindales.[23] A few authors placedGodoya,Sauvagesia, and others in the family Sauvagesiaceae, until the beginning of the 21st century.[22] Other authors, such asAdolf Engler, included them in Ochnaceae.
In 1874, Engler divided Ochnaceae into two groups, based on the absence or presence ofendosperm in the mature seed.[39] The group without endosperm corresponds to de Candolle's concept of Ochnaceae, and to the modern tribe Ochneae. The group with endosperm is now known to beparaphyletic and consists of the tribes Testuleeae, Luxemburgieae, and Sauvagesieae. In 1876, in aflora ofBrazil, Engler described many new species in Ochnaceae, especially in its largest genus,Ouratea.[40] He described 85 species inOuratea, 17 of which henamed as new species at that time. He also transferred 63 species toOuratea from other genera.
The generaQuiina andTouroulia had been known since 1775, when they were described byJean Baptiste Aublet,[41] and they were variously classified by 19th centurytaxonomists.Jacques Denys Choisy erected the family Quiinaceae (as Quiinacées) for them in 1849,[42] but he did not meet therequirements forvalid publication of abotanical name. The name Quiinaceae was validated by Engler inFlora Brasiliensis in 1888.[33][43]
The genusMedusagyne had been described byJohn Gilbert Baker in 1877, in a flora ofMauritius and theSeychelles,[44] but it was not until 1924 that it was segregated into its own monogeneric family.[45]
In 1893,Ernest Friedrich Gilg covered Ochnaceae, andAdolf Engler covered Quiinaceae for the first edition ofDie Natürlichen Pflanzenfamilien.[46][47] Engler wrote a description ofMedusagyne in asupplement to the firstedition ofDNP in 1897.[48] He placedMedusagyne under the heading "Zweifelhafte, möglicherweise zu den Guttiferae gehörige Gattung" (Doubtful, possibly a genus belonging to Guttiferae). Guttiferae is anobsolete name forClusiaceae.
In 1902,Philippe van Tieghem recognized six families in what is now the subfamily Ochnoideae.[49] These were Luxemburgiaceae, Sauvagesiaceae, Wallaceaceae, Euthemidaceae, Lophiraceae, and Ochnaceae. Three of these, (Wallaceaceae, Euthemidaceae, and Lophiraceae) were monogeneric and were erected by van Tieghem at that time. His Luxemburgiaceae included the basalclades of what is now the tribe Sauvagesieae. Van Tieghem named a great many genera in 1902, circumscribing them very narrowly. In what is now thesubtribe Ochninae, he delineated 53 genera. The most recent revision of that group divides it into six genera.
In 1925, for the second edition ofDNP, Engler and Gilg expanded on theirtreatment of Quiinaceae and Ochnaceae, respectively, compared to what they had written in 1893.[50][51] Medusagynaceae was covered in the same volume ofDNP by Adolf Engler andHans Melchior.[52]
For the second edition ofDNP, Engler recognized two genera,Quiina andTouroulia, in Quiinaceae.Lacunaria andFroesia were discovered later and named in 1925 and 1948, respectively.
In that same volume, Gilg divided his Ochnaceae (equivalent to modern Ochnoideae) into 21 genera, includingIndovethia, Leitgebia, Vausagesia, andLauradia (asLavradia), which are now regarded assynonyms ofSauvagesia.[4] Eight of the modern genera, (Philacra, Krukoviella, Fleurydora, Tyleria, Adenarake, Indosinia, Perissocarpa, andIdertia) consist of plants that had not been uncovered bybotanical exploration at that time. Gilg placedRhytidanthera in synonymy underGodoya, butRhytidanthera is accepted today. He includedCampylospermum andRhabdophyllum inGomphia and placedGomphia in synonymy underOuratea. In his revision of Ochnaceae, Gilg provided asummary of van Tieghem's classification, as well as his own.[51] Three of van Tieghem's genera, (Campylospermum,Rhabdophyllum, andRhytidanthera) are still recognized today.[4]
In 1968,Andrias Kanis published apaper that greatly influenced subsequent work in Ochnaceae, right up to the 2014 revision.[35]Claude H.L. Sastre named many new species in Ochnaceae, in severalpapers from 1970 to 2003.[5]
In 1991, acladistic analysis was published for Ochnaceae.[53] In that same year,Neckia, a 28th genus for Ochnoideae, was resurrected in amolecular phylogenetic study based on fourchloroplast DNAloci, andnuclearribosomalITS.[5] Seventy-nine species of Ochnaceae weresampled and a new classification was presented. Also,Testulea was removed from the tribe Sauvagesieae, and placed in themonotypic tribe Testuleeae.
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