Dodonaea
Hop-bushes
Hop-bushes
Wikipedia links: Angiosperms > Eudicots > Rosids > Sapindales > Sapindaceae > Dodonaeoideae > Dodonaea
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Overview:
Dodonaea, commonly known as hop-bushes, is a genus of about 70 species of flowering plants in the soapberry family, Sapindaceae
The genus has a cosmopolitan distribution in tropical, subtropical and warm temperate regions of Africa, the Americas, southern Asia and Australasia, but 59 species are endemic to Australia
Plants in the genus Dodonaea are shrubs or small trees and often have sticky foliage, with simple or pinnate leaves arranged alternately along the stems
The flowers are male, female or bisexual and are borne in leaf axils or on the ends of branchlets and lack petals
The fruit is an angled or winged capsule
Common name: Hop-bushes
Conservation status: . . .
Etymology:
The genus name (Dodonaea) honours Dodonaeus, (the latinised form of Dodoens), a Flemish physician and botanist
Flowers
The flowers have three to seven sepals but that fall of as the flowers mature, but no petals
There are six to sixteen stamens (except in female flowers), the filaments shorter than the anthers, the style is threadlike and the ovary in female flowers has two to six carpels
Fruit:
A two to six angled or winged capsule
Leaves:
The leaves are arranged alternately along the stems and are simple or pinnate
Stem & branches:
Roots:
Habit:
Shrubs or small trees that typically grow to a height of 0.1–4 m
They are dioecious, monoecious or polygamous and often have sticky foliage
Habitat:
Distribution:
The genus has a cosmopolitan distribution in tropical, subtropical and warm temperate regions of Africa, the Americas, southern Asia and Australasia
59 species are endemic to Australia
Additional notes:
Taxonomy
The genus Dodonaea was first formally described in 1754 by Philip Miller in The Gardeners Dictionary and the first species he described was Dodonaea viscosa
Species
The following is a list of Dodonaea species accepted by Plants of the World Online as at April 2024:
Dodonaea adenophora Miq.
Dodonaea amblyophylla Diels
Dodonaea amplisemina K.A.Sheph. & Rye
Dodonaea aptera Miq. – coast hop-bush (Western Australia)
Dodonaea arnhemica (S.T.Reynolds) M.G.Harr.
Dodonaea barklyana (S.T.Reynolds) M.G.Harr
Dodonaea baueri Endl.
Dodonaea biloba J.G.West
Dodonaea boroniifolia G.Don
Dodonaea bursariifolia F.Muell.
Dodonaea caespitosa Diels
Dodonaea camfieldii Maiden & Betche
Dodonaea ceratocarpa Endl.
Dodonaea concinna Benth.
Dodonaea coriacea (Ewart & O.B.Davies) McGill.
Dodonaea divaricata Benth.
Dodonaea dodecandra (Domin) M.G.Harr.
Dodonaea ericifolia G.Don
Dodonaea ericoides Miq.
Dodonaea falcata J.G.West
Dodonaea filamentosa (S.Moore) M.G.Harr.
Dodonaea filifolia Hook.
Dodonaea filiformis Link
Dodonaea glandulosa J.G.West
Dodonaea hackettiana W.Fitzg.
Dodonaea heteromorpha J.G.West
Dodonaea hexandra F.Muell.
Dodonaea hirsuta Maiden & Betche
Dodonaea hispidula Endl.
Dodonaea humifusa Miq.
Dodonaea humilis Endl.
Dodonaea inaequifolia Turcz.
Dodonaea intricata J.G.West – Gawler Ranges hop bush
Dodonaea lagunensis M.E.Jones
Dodonaea lanceolata F.Muell.
Dodonaea larraeoides Turcz.
Dodonaea lobulata F.Muell. – lobed-leaf hop bush
Dodonaea macrossanii F.Muell. & Scort.
Dodonaea madagascariensis Radlk.
Dodonaea malvacea (Domin) M.G.Harr.
Dodonaea megazyga (F.Muell.) F.Muell. ex Benth.
Dodonaea microzyga F.Muell.
Dodonaea multijuga G.Don.
Dodonaea oxyptera F.Muell.
Dodonaea pachyneura F.Muell.
Dodonaea peduncularis Lindl.
Dodonaea petiolaris F.Muell.
Dodonaea physocarpa F.Muell.
Dodonaea pinifolia Miq.
Dodonaea pinnata Sm.
Dodonaea platyptera F.Muell.
Dodonaea polyandra Merr. & L.M.Perry
Dodonaea polyzyga F.Muell.
Dodonaea procumbens F.Muell.
Dodonaea ptarmicifolia Turcz.
Dodonaea rhombifolia N.A.Wakef.
Dodonaea rigida J.G.West
Dodonaea rupicola C.T.White
Dodonaea scurra K.A.Sheph. & R.A.Meissn.
Dodonaea serratifolia McGill.
Dodonaea sinuolata J.G.West
Dodonaea sinuolata subsp. acrodentata J.G.West
Dodonaea sinuolata subsp. sinuolata J.G.West
Dodonaea stenophylla F.Muell.
Dodonaea stenozyga F.Muell.
Dodonaea subglandulifera J.G.West
Dodonaea tenuifolia Lindl.
Dodonaea tepperi F.Muell. ex Tepper
Dodonaea triangularis Lindl.
Dodonaea trifida F.Muell.
Dodonaea triquetra J.C.Wendl.
Dodonaea truncatiales F.Muell.
Dodonaea uncinata J.G.West
Dodonaea vestita Hook.
Dodonaea viscosa Jacq.
Dodonaea viscosa subsp. angustifolia (L.f.) J.G.West
Dodonaea viscosa subsp. angustissima (DC.) J.G.West
Dodonaea viscosa subsp. arizonica (A.Nelson) A.E.Murray
Dodonaea viscosa subsp. cuneata (Sm.) J.G.West
Dodonaea viscosa subsp. elaeagnoides (Rudolphi ex Ledeb. & Adlerstam) Acev.-Rodr.
Dodonaea viscosa subsp. mucronata J.G.West
Dodonaea viscosa subsp. spatulata (Sm.) J.G.West
Dodonaea viscosa Jacq. subsp. viscosa
Systematics
Dodonaea is one of the largest genera in the Sapindaceae, and includes 70 species widely distributed in continental Australia
The only other species of the Dodonaea widely spread beyond mainland Australia, Dodonaea viscosa, is believed to be one of the world's most greatly disseminated transoceanic plants
The first attempts to distinguish infrageneric categories within genus Dodonaea were based on leaf morphology, specifically, two sections - Eu-Dodonaea (simple leaves) and Remberta (pinnate leaves) were differentiated
Later this sectional classification was expanded by Bentham, who included 39 species in five series - four simple-leaved series further divided on capsule-appendage morphology (series Cyclopterae, Platypterae, Cornutae and Apterae) and one pinnate-leaved species (series Pinnatae)
Later the genus was reviewed extensively two times. Radlkofer identified Dodonaea as a part of the tribe Dodonaeeae, within Dyssapindaceae, together with Loxodiscus, Diplopeltis and Distichostemon. Dodonaea and Distichostemon share similar morphological characteristics which include plants having regular flowers without petals and an intrastaminal disc
Therefore, these two genera are considered to be closely related
54 Dodonaea species identified by Radlkofer were divided into three series (Cyclopterae, Platypterae and Aphanopterae) and six subseries
Another revision of the genus was proposed by West, where Dodonaea were divided into six species groups by using a combination of characters
Species with the most primitive characters were classified in Group 1 and Group 6 included plants with the most derived states
For instance, the character of an aril possession was recognized as a derived trait
The most recent molecular study of phylogenetic relationships within the genus revealed some discrepancy with the previously stated hypotheses of morphological evolution within Dodonaea which classified taxa by the combination of leaf, capsule and seed characters. As in preceding morphological research, species with compound leaves were identified in several clades, interspersed among species with simple leaves (e.g. D. humilis is the only species in Clade I with imparipinnate leaves)
The breeding system has great variation across the phylogeny, and although most species are dioecious, sometimes some species may differ from this state being monoecious
Most genera in Sapindaceae are dioecious, however, most closely related to Dodonaea in the phylogeny (Diplopeltis, Diplopeltis stuartii and Cossinia) are monoecious
It has also been reported that whereas normally breeding system in Harpullia is dioecism, a few species have also been recognized as monoecious
It was stated that during evolution a general breeding-system across the phylogeny was dioecism, however, the polygamous state was intermediate or, might be partially reversible
Molecular data supports an evidence that monophyly of Dodonaea includes all species of Distichostemon
It is also supported by the morphological characters as synapomorphies of flowers with reduced petal number and with a highly reduced intrastaminal disk, the trait which is absent in staminate flowers
Both West and Radlkofer used an aril presence or absence as a character to define species groups. All the main clades of Dodonaea and also two species of Diplopeltis have small funicular arils
Seeds of D. viscosa have very small funicular aril, and are harvested by Pheidole ants and deposited in middens outside the nest after the elaiosome has been consumed
Bayesian MCMC estimation of Dodonaea phylogeny supported the hypothesis that two species of Cossinia are sisters to Diplopeltis and Dodonaea
Nevertheless, Diplopeltis is identified as a paraphyletic group. The monophyly of Dodonaea is well supported by Bayesian MCMC estimation (1.00 posterior probability, PP)
Dodonaea viscosa is placed within the Clade IV, being closely related to D. biloba, D. procumbens and D. camfieldii. It is known that D. viscosa and D. camfieldii evolved in Australia from their most recent common ancestor
Sources of information: