Jump to content

Saxifragales: Difference between revisions

From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
→Books: Brennan 1996
→Books: Brennan 2008
Line 362: Line 362:


* {{cite book|editor-last1=Janick|editor-first1=Jules|editor-last2=Moore|editor-first2=James N.|last= Brennan|first=Rex M.|title=Fruit Breeding. II: Vine and small fruits|url=https://books.google.ca/books?id=OXMckUtHLV8C|date= 1996|publisher=[[Wiley (publisher)|Wiley]]|chapter=Currants and Gooseberries|chapter-url=|pages=191–298|isbn=978-0-471-12670-6|ref=harv}}
* {{cite book|editor-last1=Janick|editor-first1=Jules|editor-last2=Moore|editor-first2=James N.|last= Brennan|first=Rex M.|title=Fruit Breeding. II: Vine and small fruits|url=https://books.google.ca/books?id=OXMckUtHLV8C|date= 1996|publisher=[[Wiley (publisher)|Wiley]]|chapter=Currants and Gooseberries|chapter-url=|pages=191–298|isbn=978-0-471-12670-6|ref=harv}}
* {{cite book|last=Hancock|first=Jim F.|title=Temperate Fruit Crop Breeding: Germplasm to Genomics|url=https://books.google.com/books?id=322hHeocPa0C|last=Brennan|first=R. M.|chapter=Currants and Gooseberries|chapter-url=https://link.springer.com/chapter/10.1007/978-1-4020-6907-9_6|pages=177–196|date= 2008|publisher=[[Springer Science & Business Media]]|isbn=978-1-4020-6907-9}}
* {{cite book|last1=Byng|first1=James W.|authorlink=James W. Byng|title=The Flowering Plants Handbook: A practical guide to families and genera of the world|date=2014|publisher=Plant Gateway Ltd.|isbn=978-0-9929993-1-5|url=https://books.google.com/books?id=yoLaBAAAQBAJ|chapter=Saxifragales|pages=156–166|ref=harv}}
* {{cite book|last1=Byng|first1=James W.|authorlink=James W. Byng|title=The Flowering Plants Handbook: A practical guide to families and genera of the world|date=2014|publisher=Plant Gateway Ltd.|isbn=978-0-9929993-1-5|url=https://books.google.com/books?id=yoLaBAAAQBAJ|chapter=Saxifragales|pages=156–166|ref=harv}}
* {{cite book|last1=Christenhusz|first1=Maarten J. M.|last2=Fay|first2=Michael F.|last3=Chase|first3=Mark W.|authorlink1=Maarten Christenhusz|authorlink2=Michael F. Fay|authorlink3=Mark W. Chase|title=Plants of the World: An Illustrated Encyclopedia of Vascular Plants|url=https://books.google.com/books?id=LLo7DwAAQBAJ|date= 2017|publisher=[[University of Chicago Press]]|isbn=978-0-226-52292-0|chapter=Saxifragales|pages=231–244|ref={{harvid|Christenhusz et al|2017}}}}
* {{cite book|last1=Christenhusz|first1=Maarten J. M.|last2=Fay|first2=Michael F.|last3=Chase|first3=Mark W.|authorlink1=Maarten Christenhusz|authorlink2=Michael F. Fay|authorlink3=Mark W. Chase|title=Plants of the World: An Illustrated Encyclopedia of Vascular Plants|url=https://books.google.com/books?id=LLo7DwAAQBAJ|date= 2017|publisher=[[University of Chicago Press]]|isbn=978-0-226-52292-0|chapter=Saxifragales|pages=231–244|ref={{harvid|Christenhusz et al|2017}}}}

Revision as of 19:40, 16 December 2019

Saxifragales
Temporal range: 89.5–0 Ma Turonian - Recent
Corylopsis pauciflora
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Core eudicots
Clade: Superrosids
Order: Saxifragales
Bercht. & J.Presl[1]
Type genus
Saxifraga L.
Families[1]
Synonyms
  • Cercidiphyllales
  • Crassulales
  • Daphniphyllales
  • Grossulariales
  • Haloragales
  • Hamamelidales
  • Iteales
  • Paeoniales
  • Sedales

The Saxifragales or saxifrages are an order of flowering plants. Their closest relatives are a large eudicot group known as the rosids, following the definition of the Angiosperm Phylogeny Group classification system. Saxifragales is one of the groups that compose the core eudicots, which consists of the Dilleniaceae, superasterids and superrosids, the latter consisting of the Saxifragales and rosids.

The Saxifragales order is based upon the results of molecular phylogenetic studies of DNA sequences. It is not part of any of the classification systems based on plant morphology. The group is much in need of comparative anatomical study, especially in light of the recent expansion of the family Peridiscaceae to include Medusandra, a genus that before 2009 had usually not been placed in Saxifragales.

The order is divided into suprafamilial groups as shown on the phylogenetic tree below. These groups are informal and are not understood to have any particular taxonomic rank.

Description

The order Saxifragales is extremely morphologically diverse (hyper-diverse). It includes trees (e.g. witch hazel, witch alder in Hamamelidaceae), fruit bearing shrubs (e.g. currants, gooseberries in Grossulariaceae), lianas, annual and perennial herbs, rock garden plants (e.g. saxifrage in Saxifragaceae), ornamental garden plants (e.g. peonies in Paeoniaceae) succulents (e.g. stonecrop in Crassulaceae), and aquatics (e.g. watermilfoil in Haloragaceae).[2] The flowers demonstrate variation in sepal, petal, stamen, and carpel number, as well as ovary position.[3] This degree of diversity makes synapomorphy unclear, but partially fused bicarpellate gynoecia (unfused at least toward the apex), a hypanthium, and glandular leaf teeth are potential synapomorphies. Common traits include flowers that are usually radially symmetric, petals that are free, and seeds with abundant endosperm. While the families of the woody clade are primarily woody, the primarily herbaceous families of Crassulaceae and Saxifragaceae exhibit woody features as a secondary transition.[4][5]

Taxonomy

With 15 families, about 100 genera and about 2,470 species, Saxifragales is a relatvely small angiosperm order.[3]

History

Saxifragales was first described in 1820 by Berchtold and Presl in 1820 as a group of plants, Saxifrageae, with five genera, including Saxifraga, an therefore bear their names as the botanical authority (Bercht. & J.Presl).[6] At times, that authority has also been given to Dumortier, due to a later publication (1829). Dumortier first used the word Saxifragaceae.[7] By the time of John Lindley's The Vegetable Kingdom (1853), the term Saxifragales was in use, which Lindley called an Alliance, containing five families.[8] Later, the Saxifragales were placed in the angiosperm class Dicotyledons, also called Magnoliopsida.[9]

Phylogeny

The order Saxifragales has undergone considerable revision in both placement and composition, since the use of molecular phylogenetics, and the use of the modern Angiosperm Phylogeny Group (APG) classification.[1][10] They are identified as a strongly monophyletic group.[11]

In the initial APG publication (1998), the Saxifragales were identified within the core eudicots clade but its relationship to other clades was uncertain. The core eudicots consist of the order Gunnerales and a large clade of Pentapetalae (so named for having a synapomorphy of pentamerous perianths), the latter representing about 70% of all angiosperms, with eight major lineages.[12][13] Later (2003) the order was described as "one of the major surprises of molecular phylogenetic analyses of the angiosperms", having elements previously placed in three or four separate subclasses based on morphology.[14][3] This was eventually resolved in the third APG system (2009) placing Saxifragales as a sister group to the rosids (Rosidae), within the Pentapetalae clade.[15][16][17] This large combination has subsequently been given the name superrosids (Superrosidae), representing part of an early diversification of the angiosperms.[3][1][18] Among the rosids, they share a number of similarities with the Rosales, particularly Rosaceae, including a hypanthium, five part flowers and free floral parts.[19] As circumscribed, Saxifragales account for 1.3% of eudicot diversity.[20]

Cladogram of Saxifragales relationships among core eudicots[1][10][21]
Core eudicots

Gunnerales

126
Pentapetalae

superasterids

Dilleniales

125
superrosids

rosids

116

Saxifragales

108
124
128
130
Numbers indicate divergence times in Myr

Biogeography and evolution

Diversification among Saxifragales was rapid, with the extensive fossil record[22][23][24][25][26][27] indicating that the order was more diverse and more widespread than an examination of the extant members suggests, with considerable phenotypic diversity occurring early.[2] The earliest fossil evidence is found in the Turonian-Campanian (late Cretaceous), suggesting a minimum age of 89.5 Myr. However, molecular divergence time estimation suggest an earlier time of 102–108 Myr, into the early Cretaceous, for the crown and stem groups respectively. Within the order Saxifragales, the molecular data imply a very rapid initial diversification time of about 6–8 Myr, between 112–120 Myr, with major lineages appearing within 3–6 Myr.[28][3][29]

The ancestral state appears to be woody, as in Peridiscaceae and the woody clade, but also ancestral to Grossulariaceae. A number of independent transitions to a herbaceous habit in the ancestors of Crassulaceae, Saxifragaceae and the base of the Haloragaceae-Penthoraceae clade, the other two families in Haloragaceae s.l. remaining woody, while other taxa reverted to a woody habit, especially Crassulaceae. Most of Saxifragaleshave a superior ovary, but some families show frequent transition with inferior or subinferior position, particularly Saxifragaceae and to a lesser extent Hamamelidaceae. Almost all Grossulariaceae have an inferior ovary. The ancestral carpel number is two, with transition to higher numbers, such as four in Haloragaceae s.l. and Peridiscaceae with five in Penthoraceae. The ancestral number for Crassulaceae is two, decreasing to Kalanchoe, where it is synapomorphic, though the most frequent transition in this family is 6–10, but only where stamen number is increased above five. Some Macronesian taxa (Aeonieae) have 8–12, with up to 32 carpels for Aeonium.[3]

The ancestral petal number is five, with three major transitions; 5 to 0, 5 to 4, 5 to 6–10. Increased petal number is seen in Paeoniaceae and Crassulaceae, particularly where stamen number is also increased. Cercidiphyllum + Daphniphyllum, Chrysosplenium and Altingia are examples of the complete loss of petals. The ancestral stamen:petal ratio is 1, with transitions characterising several clades, e.g. Paeonicaceae+woody clade >2, Crassulaceae 2 (but Crassula 1). Overall there has been a decrease over evolution, but independent of a decrease in petal number, so that it is the stamen number that has decreased.[3] The ancestral habitat appears to be forests, followed by early diversification into desert and aquatic habitats, with shrubland the most recent colonization.[2]

Species diversification was rapid following a transition from a warmer, wetter Earth in the Eocene (56–40 Myr) to early Miocene (23–16 Myr), to the cooler drier conditions of the mid-Miocene (16–12 Myr). However, this appears to not have coincided with ecological and phenotypic evolution, which are themselves correlated. There is a clear lag, whereby increase in species diversification was followed later by increases in niche and phenotypic lability.[30]

Subdivision

The first APG classification (1998) placed 13 families with the order Saxifragales:[31]

This was subsequently revised to 15, in the fourth version (2016).[1]

The Saxifragales families have been grouped into a number of informally named suprafamilial subclades, with the exception of the basal split of Peridiscaceae, which thus forms a sister group with the rest of Saxifragales. The two major ones are (Paeoniaceae + the woody clade of primarily woody families) and the "core" Saxifragales (i.e. the primarily herbaceous families), with the latter subdivided into two further subclades, (Haloragaceae sensu lato + Crassulaceae) and the Saxifragaceae alliance.[3]

In the clade Haloragaceae sensu lato (s.l.) + Crassulaceae the genera constituting Haloragaceae s.l. are all small, and APG II (2003) proposed merging them into a single larger Haloragaceae s.l., but transferred Aphanopetalum from Cunoniaceae to this group.[14] The Saxifragaceae alliance represents Saxifragaceae together with a number of woody members of the traditional Saxifragaceae sensu Engler (1930).[32] Within this, APG II (2003) proposed placing the two species of Pterostemon that constitute Pterostemonaceae within Iteaceae, and all subsequent versions have maintained this practice.[14] Thus Saxifragales sensu APG II consisted of only 10 families. The third version (2009) added Peridiscaceae (from Malpighiales), as sister to all other families, but re-expanded Haloragaceae to provide for a narrower circumscription, Haloragaceae sensu strictu (s.s.) to give a total of 14 families. APG IV (2016) added the parasitic family Cynomoriaceae to provide 15 families, although its placement within the order remained unclear.[33][1]

Of the families included in APG IV, the basal divergence Peridiscaceae underwent radical shifting and recircumscription from 2003 to 2009. Originally, it consisted of two closely related genera, Peridiscus and Whittonia. The APG II system placed the family in Malpighiales, based on a DNA sequence for the rbcL gene from Whittonia. This sequence turned out to be not from Whittonia, but from other plants whose DNA had contaminated the sample.[34] After placement in Saxifragales, it was expanded to include Soyauxia in 2007,[35] and Medusandra in 2009.[36]

In the first of the subclades of the remaining Saxifragales, Paeoniaceae possesses many unique features and its taxonomic position was controversial for a long time,[37] and Paeonia was placed in Ranunculales, close to Glaucidium,[38][39] prior to transfer to Saxifragales as sister to the woody clade.[28][40]

In the woody clade, the genus Liquidamber was included in Hamamelidaceae until molecular phylogenetic studies showed that its inclusion might make Hamamelidaceae paraphyletic, and was segregated as a separate monotypic family, Altingiaceae in 2008.[28] Cercidiphyllaceae was for a long time associated with Hamamelidaceae and Trochodendraceae and was often thought to be closer to the latter,[41] which is now in the basal eudicot order Trochodendrales.[42] Daphniphyllum was always thought to have an anomalous combination of characters[43][43] and was placed in several different orders before molecular phylogenetic analysis showed it to belong to Saxifragales.[44]

In the core Saxifragales, Crassulaceae[45] and Tetracarpaeaceae[46] have been associated with Saxifragaceae, while Penthorum has been associated both with Crassulaceae and Saxifragaceae,[47] before being placed here. Aphanopetalum was often placed in Cunoniaceae, a family in Oxalidales, even though there were good reasons to put it in Saxifragales,[48] and it was subsequently transferred.[49] Haloragaceae was included in Myrtales,[50] before being placed in Saxifragales.[51]

The other "core" group, the Saxifragaceae alliance comprises four families: Pterostemonaceae, Iteaceae, Grossulariaceae, and Saxifragaceae,[28] which have long been known to be related to each other, but the circumscription of Saxifragaceae has been much reduced and Pterostemonaceae submerged as Pterostemon in Iteaceae.[52]

Most of the families are monogeneric. Choristylis is now considered a synonym of Itea, but the addition of Pterostemon, gives Iteaceae two genera.[53] Liquidambar and Semiliquidambar are also submerged into Altingia, making Altingiaceae monogeneric.[54][55] About 95% of the species are in five families: Crassulaceae (1400), Saxifragaceae (500), Grossulariaceae (150–200), Haloragaceae (150), and Hamamelidaceae (100). The number of genera in each family is:[20][28][56]

The phylogeny in this cladogram still has uncertainty as to the exact relationships, and the phylogenetic tree is subject to further revision.[57][58] Cynomoriaceae, previously placed in Santales or Rosales is included in Saxifragales, but unplaced within it. Li et al.(2019) have slightly different relationships, and also place Cynomoriaceae as the first branch in the Crassulaceae+Haloragaceae s.l. tree, i.e. as sister to those two families.[29]

Cladogram of Saxifragales families[28][20][1]
Saxifragales

Peridiscaceae (4)

 97 

Paeonia (Paeoniaceae)

 woody clade 

Liquidamber (Altingiaceae)

 69 
 98 

Hamamelidaceae (27)

 95 

Cercidiphyllum (Cercidiphyllaceae)

Daphniphyllum (Daphniphyllaceae)

 core Saxifragales 

Crassulaceae (34)

 Haloragaceae s.l.

Aphanopetalum (Aphanopetalaceae)

Tetracarpaea (Tetracarpaeaceae)

Penthorum (Penthoraceae)

Haloragaceae s.s. (8)

 Saxifragaceae alliance 

Iteaceae (including Pterostemonaceae) (2)

Ribes (Grossulariaceae)

Saxifragaceae (33)

100% maximum likelihood bootstrap support except where labeled with bootstrap percentage
Monogeneric families are represented by genus names, otherwise the number of genera is in (parentheses)
Cynomorium (Cynomoriaceae) remains unplaced within this tree

Families

Botanical illustration of Peridiscus lucidus
Peridiscus lucidus

Peridiscaceae

Main article: Peridiscaceae

The Peridiscaceae (Ringflower family) are a small tropical family of 4 genera and 11–12 species of small trees and shrubs found in the Guiana Shield of S America (2 genera, one of which, Whittonia, is thought to be extinct) and West and Central Africa (2 genera). The majority of species occur in the African genus Soyauxia. The name comes from the Greek, peri (around) discos (ring).[5][59][19]

Paeonia officinalis growing in Hungary
Paeonia officinalis

Paeoniaceae

Main article: Paeoniaceae

The Paeoniaceae (Peony family) consist of a single genus (Paeonia) with about 33 species of perennial herbs and small shrubs with showy flowers, found from the Mediterranean to Japan, but two species occur in western N America. They are commercially important as popular garden ornamentals, cultivated since antiquity, and have been used medicinally. The herbaceous varieties are derived from P. lactiflora, while the shrubs are derived from P. suffruticosa (tree peony), both Asian species. The botanical name comes from its Greek name, paionia, named in turn for the God Pan.[5][59][19]

Liquidambar styraciflua tree
Liquidambar styraciflua

Altingiaceae

Main article: Altingiaceae

The Altingiaceae (Sweetgum family) consist of a single genus (Liquidambar) with 15 species of trees with unisexual flowers found in Eurasia, but with one species in North and Central America, Liquidambar styraciflua (American sweetgum). Liquidamber is used for its resin and timber, as well being ornamental trees. The nominative genus and family are named after Willem Alting, and Liquidambar for liquid ambar, Arabic for the resin.[5][59][19]

Branch of Hamamelis virginiana showing flowers and leaves
Hamamelis virginiana

Hamamelidaceae

Main article: Hamamelidaceae

The Hamamelidaceae (Witch-hazel family) consists of trees and shrubs with a widespread distribution, but main centres in East Asia and Malaysia. They are found in wet woodlands and forested slopes. The family has 26 genera and about 80–100 species, in five subfamilies, of which the nominative, Hamamelidoideae, contains over 75% of the genera. The species have uses as medicaments, timber and ornamental plants for their flowers, such as Hamamelis (witch hazel) or leaves, such as Parrotia persica (Persian ironwood). The family and nominative genus is named for the Greek hamamelis, the wych elm.[59][19][5]

Cercidiphyllum japonicum
Cercidiphyllum japonicum

Cercidiphyllaceae

Main article: Cercidiphyllaceae

The Cercidiphyllaceae (Caramel-tree family) are a small family of deciduous trees found in China and Japan, with a single genus, Cercidiphyllum and two species, C. japonicum and C. magnificum. The trees are valued for their wood (katsura) and as ornamentals. C. japonicum is the largest deciduous tree in Japan. The name is derived from the Greek words kerkis (poplar) and fyllon (leaf), from a supposed similarity in leaves.[59][19]

Daphniphyllum macropodum
Daphniphyllum macropodum

Daphniphyllaceae

Main article: Daphniphyllaceae

The Daphniphyllaceae (Laurel-leaf family) consist of a single genus, Daphniphyllum, with about 30 species. They are evergreen unisexual trees and shrubs distributed in SE Asia and the Solomon Islands. The dried leaves of D. humile have been used for smoking in Japan and Siberia. The name is derived from the Greek words dafne (laurel) and fyllon (leaf), from a supposed resemblance to the leaves of the former (Laurus nobilis).[59][19]

Crassula perfoliata
Crassula perfoliata

Crassulaceae

Main article: Crassulaceae

The Crassulaceae (Orpine and Stonecrop family) are a medium size diverse and cosmopolitan family, that form the largest family within Saxifragales. They are mainly succulent, rarely aquatic, with a specialised form of photosynthesis (Crassulacean Acid Metabolism). Genera vary from 7 to 35, depending on the circumscription of the large genus Sedum, and there are about 1,400 species. Uses are diverse, including spices, medicaments and roof coverings as well as ornamental rock garden and household plants such as the S African Crassula ovata, the jade or money plant. The name is derived from the Latin, crassus (thick), referring to the fleshy leaves.[59][19][5]

Aphanopetalum resinosum vine
Aphanopetalum resinosum

Aphanopetalaceae

Main article: Aphanopetalaceae

The Aphanopetalaceae (Gum-vine family) consists of a single genus of Australian climbing shrubs, Aphanopetalum, which has two species, A. clematidium Aphanopetalum clematideum (SW Australia) and A. resinosum (Queensland, NSW). The name is derived from the Greek words afanos (inconspicuous) and petalon (petal).[59][19]

Flowers of Tetracarpaea tasmannica
Tetracarpaea tasmannica

Tetracarpaeaceae

Main article: Tetracarpaeaceae

The Tetracarpaeaceae (Delicate-laurel family) is a very small evergreen Australian shrub family with a single genus, Tetracarpaea and a single species, T. tasmannica, confined to subalpine Tasmania. The name is derived from the Greek words tetra (four) and carpos (fruit), referring to the ovaries which have four carpels.[59][19][5]

Flowers of Penthorum sedoides
Penthorum sedoides

Penthoraceae

Main article: Penthoraceae

The Penthoraceae (Ditch-stonecrop family) is a very small family of rhizomatous perennial herbs found in eastern N America and E Asia, in mainly wet environments. It consists of a single genus, Penthorum with two species, P. sedoides in N America and P. chinense from Siberia to Thailand. P. sedoides is used in aquaria and water gardens.[60] The name is derived from the Greek word pente (five) referring to the five-part fruit.[59][19][5]

Flowers and leaves of Haloragis erecta
Haloragis erecta

Haloragaceae

Main article: Haloragaceae

The Haloragaceae (Water-milfoil family) is a small family of trees, shrubs, perennial, annual terrestrial, marsh and aquatic herbs with global distribution, but especially Australia. It consists of 9–11 genera and about 145 species. The largest genus is Gonocarpus with about 40 species. The major horticultural genus is Myriophyllum (watermilfoil) whose species are valued as aquaria and pond plants but may escape and naturalise, becoming invasive. Some cultivars of Haloragis are valued as ornamentals.[60] Only one genus, Haloragodendron, is a shrub and is confined to S Australia. The family and nominative genus, Haloragis are named from the Greek words halas (salt) and rhoges (berries).[59][19][5]

Itea virginica plant
Itea virginica

Iteaceae

Main article: Iteaceae

The Iteaceae (Sweetspire family) is a widespread small family of trees and shrubs, with 2 genera, and 18–21 species, found in tropical to northern temperate regions. The larger genus, Itea (c. 16 spp.) is more widespread, from the Himalayas to Japan and western Malesia and one species in eastern N America (I. virginica) whereas Pterostemon (c. 2 spp) is confined to Oaxaca, Mexico. I. virginica and I. ilicifolia, from China, are valued as ornamental shrubs. The name is derived from the Greek word itea (willow) for its rapid growth and similar leaf form.[59][19][5]

Fruit and leaves of Ribes rubrum
Ribes rubrum

Grossulariaceae

Main article: Grossulariaceae

The Grossulariaceae (Gooseberry family) are shrubs that are usually deciduous. The single genus, Ribes, has about 150 species that are commercially important and widely cultivated for their fruit and also grown as ornamentals, such as R. uva-crispa (gooseberry) and R. nigrum (blackcurrant). They are found in temperate northern hemisphere regions but extending through the Andes into S America. The family name is derived from the Latin word grossulus (an unripe fig), and Ribes is latinised from the semitic word ribas (acid taste).[59][19][5]

Flowers of Saxifraga granulata
Saxifraga granulata

Saxifragaceae

Main article: Saxifragaceae

The Saxifragaceae (Saxifrage family) are mainly perennial herbs distributed throughout the Northern Hemisphere and Andes, and New Guinea, in damp woodlands and cooler northern regions, rarely aquatic, but are adapted to a wide range of moisture conditions. The family, greatly reduced, includes 35 genera and about 640 species, in two lineages, saxifragoids (e.g. Saxifraga, rockfoil) and heucheroids (e.g. Heuchera, coral bells). The largest genus is Saxifraga, the type genus (370 species), though several genera are monotypic. Saxifragaceae are the most horticulturally important of the herbaceous Saxifragales. They provide foodstuffs and medicaments and include many ornamentals, particularly of border, rock and woodland gardens, such as Astilbe, though the largest number of cultivated species belong to Saxifraga. The family and type genus name are derived from the two Latin words saxum (rock), and frango (to break), but the exact origin is unknown, although surmised to be either because of the ability of Saxifraga to grow in crevices in rocks or medicinal use for kidney stones.[59][19][5]

Inflorescence of Cynomorium coccineum
Cynomorium coccineum

Cynomoriaceae

Main article: Cynomoriaceae

The Cynomoriaceae (Tarthuth or Maltese Mushroom family) consists of a single genus, Cynomorium with two species, C. coccineum (Mediterranean basin) and C. songaricum (central Asia and China). They are perennial bisexual herbaceous parasitic plants lacking chlorophyll, from deserts and arid regions. They have been harvested for food, as a dye and in traditional medicine. The name is derived from two Greek words kynos (dog), and morion (penis), for its shape.[59][19]

Distribution and habitat

Saxifragales are found worldwide,[5] though primarily in temperate zones and rarely in the tropics.[59] They occupy a wide variety of habitats from arid desert (Crassulaceae) to aquatic conditions (Haloragaceae), with 6 families, including North American species, that are obligate aquatic (fully dependant on an aquatic environment),[61] and including forests, grasslands and tundra. Saxifragales exceeds all other comparably sized clades in terms of diversity of habitats.[2] Most of the diversity occurs in temperate (including montane and arid) conditions that expanded globally during cooling and drying trends in the last 15 My.[30]

The commonest habitats are forests and cliffs, with about 300 species each, but forests being the most diverse phenotypically, with nearly all families represented. In contrast desert and tundra, with only two families each, contain only about 10% of species. About 90% of species can be assigned to a single habitat.[2]

Conservation

Whittonia (Peridiscaceae) is thought to be extinct. As of 2019 the IUCN lists 9 critically endangered, 12 endangered, 19 vulnerable and 7 near threatened species. Among the most threatened Saxifragales are Aichryson dumosum and Monanthes wildpretii (Crassulaceae), Haloragis stokesii and Myriophyllum axilliflorum (Haloragaceae), Ribes malvifolium and R. sardoum (Grossulariaceae) and Saxifraga artvinensis (Saxifragaceae) and Molinadendron hondurense (Hamamelidaceae).[62]

Uses

Plants in the order Saxifragales have found a wide variety of uses, including traditional medicines, ornamental household, aquarium, pond and garden plants, spices, foodstuffs (fruit and greens), dyestuffs, smoking, resin, timber and roof coverings.[59]

Cultivation

A number of Saxifragales genera are commercially cultivated.[59] Paeonia are cultivated both as ornamental shrubs (generally sold as root stock) and for cut flowers, with the Netherlands representing the largest production, other more minor producers are Israel, New Zealand, Chile and the United States.[63] Liquidamber is used for hardwood, with the American Sweetgum (Liquidambar styraciflua) being among the most important sources of commercial hardwood in the Southeast United States, with one of its uses being veneer for plywood.[64] Hamamelis is cultivated in New England for distilleries extracting witch-hazel, widely used in skincare, and is the largest source of this medicament in the world.[65] Among the Crassulaceae, economic importance is limited to horticulture, with many species and cultivars are economically important as ornamentals, including Crassula ovata (jade plant) and Jovibarba (hen and chicken). Hylotelphium, Phedimus, Sedum and Sempervivum are cultivated for rock gardens and for "green roofs".[66][45] In particular, cultivars of the Madagascan Kalanchoe blossfeldiana, e.g. 'Florists kalanchoe' have achieved commercial success throughout the world, being popular Christmas decorative plants.[67][68] The Haloragaceae aquatic genus Myriophyllum and the closely related Proserpinaca are cultivated for the commercial aquarium trade.[69] Myriophyllum is also economically important for purification of water and as feed for pigs, ducks, and fish, and polishing wood.[70]

Fields of black currants growing in U.K.
Black currant crops, UK

A number of Ribes (Grossulariaceae) are in commercial production, concentrated in Europe and the USSR from species native to those areas. R. nigrum (black currant) was first cultivated in monastery gardens in Russia in the 11th century, and currant cultivation more generally later in Western Europe, R. uva-crispa (gooseberry) production began around 1700. The first colonists in N America began cultivating currants in the late 1700s. R. nigrum is the most important commercial currant crop, being produced in more than 23 countries, with the major centres being Russia (more than 63 thousand hectares), Poland and Germany. An important source of Vitamin C, black currants are used in the manufacture of jam, fruit jelly, compote, syrup, juice and other drinks, including the liqueur Cassis. Other commercial crops include R. rubrum (red currant).[71][72]

References

  1. ^ a b c d e f g h APG IV 2016.
  2. ^ a b c d e Casas et al 2016.
  3. ^ a b c d e f g h Soltis et al 2013.
  4. ^ Soltis et al 2006.
  5. ^ a b c d e f g h i j k l m Berry 2017.
  6. ^ Berchtold & Presl 1820, pp. 259–60.
  7. ^ Dumortier 1829, p. 38.
  8. ^ Lindley 1853, pp. 566–575.
  9. ^ Singh 2004.
  10. ^ a b Cole et al 2019.
  11. ^ Kubitzki 2007.
  12. ^ Moore et al 2010.
  13. ^ Zeng et al 2017.
  14. ^ a b c APG II 2003.
  15. ^ Burleigh et al 2009.
  16. ^ Wang et al 2009.
  17. ^ APG III 2009.
  18. ^ Soltis et al 2018, Superrosids pp. 191–246.
  19. ^ a b c d e f g h i j k l m n o p Byng 2014.
  20. ^ a b c Stevens 2019.
  21. ^ Tank et al 2015.
  22. ^ Hermsen et al 2006.
  23. ^ Hermsen et al 2003.
  24. ^ Pigg et al 2004.
  25. ^ Hernández-Castillo & Cevallos-Ferriz 1999.
  26. ^ Crane 1989.
  27. ^ Endress 1989.
  28. ^ a b c d e f Jian et al 2008.
  29. ^ a b Li et al 2019.
  30. ^ a b Folk et al 2019.
  31. ^ APG I 1998.
  32. ^ Engler 1930.
  33. ^ Bellot et al 2016.
  34. ^ Davis & Chase 2004.
  35. ^ Soltis et al 2007.
  36. ^ Wurdack & Davis 2009.
  37. ^ Tamura 2007.
  38. ^ Mabberley 2008.
  39. ^ Halda & Waddick 2010.
  40. ^ Wang et al 2009a.
  41. ^ Endress 1986.
  42. ^ Worberg et al 2007.
  43. ^ a b Tseng-Chieng 1965.
  44. ^ Kubitzki 2007b.
  45. ^ a b Thiede & Eggli 2007. sfn error: multiple targets (2×): CITEREFThiedeEggli2007 (help)
  46. ^ Hils et al 1988.
  47. ^ Thiede 2007.
  48. ^ Dickison et al 1994.
  49. ^ Bradford et al 2004.
  50. ^ Kubitzki 2007a.
  51. ^ Moody & Les 2007.
  52. ^ Soltis et al 2001.
  53. ^ Kubitzki 2007c.
  54. ^ Ickert-Bond & Wen 2006.
  55. ^ Ickert-Bond & Wen 2013.
  56. ^ Kubitzki 2007, pp. 15–18.
  57. ^ Dong et al 2018.
  58. ^ Ding et al 2019.
  59. ^ a b c d e f g h i j k l m n o p q r Christenhusz et al 2017.
  60. ^ a b Les 2017.
  61. ^ Les 2017, p. 745.
  62. ^ IUCN 2019.
  63. ^ Auer & Greenberg 2009.
  64. ^ Kormanik 1990.
  65. ^ Gapinski 2014.
  66. ^ Earle & Lundin 2012.
  67. ^ Smith et al 2019.
  68. ^ Gwaltney-Brant 2012.
  69. ^ Goldstein et al 2000.
  70. ^ Chen & Funston 2004.
  71. ^ Doronina & Terekhina 2009.
  72. ^ Gros d'Aillon 2016.

Bibliography

Books

Historical

Chapters

Articles

Angiosperms
Eudicots
Saxifragales

APG

Saxifragales families

Paleontology

Websites


Wikimedia Commons has media related to Saxifragales.
Wikispecies has information related to Saxifragales.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Saxifragales&oldid=931068653"