Malvaceae
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 Least Mallow, Malva parviflora
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Bombacoideae |
Malvaceae, or the mallow family, is a family of flowering plants containing a number of genera, generally with five showy petals and five green sepals and numerous stamens that are fused at the base and form a tube around the pistil. Most species are herbs or shrubs but some species are trees. There are over 100 genera with close to 1,500 species in the family depending on the classification of some of the genera. Most species have stellate hairs and mucus like sap. The best recognized genera include Malva, Abutilon, Althaea, Lavatera, Abelmoschus, Malope, Hibiscus plus others that are grown as garden plants over many regions of the world. A number are pest species in agriculture, including Abutilon theophrasti and Modiola caroliniana plus others that are garden escapes. Cotton (4 species of Gossypium), kenaf (Hibiscus cannabinus) and okra (Abelmoschus esculentus) are important agricultural crops.
There are two main views on the circumscription of the family. One view takes the traditionally narrow view of the family, Malvaceae sensu stricto. The APG II system takes a broader circumscription on the basis of molecular phylogenies that show that while Malvaceae s.s. is cladistically monophyletic, several closely related families of order Malvales are not monophyletic. This definition of the family unites the core Malvales of the Cronquist system, including Bombacaceae, Malvaceae s.s., Sterculiaceae and Tiliaceae, into the wider Malvaceae sensu lato.
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[edit] Malvaceae sensu stricto
That Malvaceae s.s. comprise a cladistically monophyletic group has been confirmed by recent molecular phylogenies. It is a homogeneous taxon, so homogeneous that the subfamily category is not applicable, Malvaceae s.s. is only subdivided in tribes.
The family most closely related to Malvaceae s.s. is Bombacaceae, and the two are separated primarily on the basis of pollen characters (smooth or rugose in Bombacaceae, spiny in Malvaceae). Malvaceae s.s. also tend to be herbs or shrubs, whereas Bombacaceae are usually trees. Molecular phylogenies have demonstrated that Bombacaceae is cladistically paraphyletic with respect to Malvaceae s.s.
It has been recognised by most compilers of high-level classifications, including:
- A. P. de Candolle (1824-1873)
- Bentham & Hooker (1862-1883) (except for Bombacaceae, considered tribe Bombaceae in Malvaceae)
- Eichler (1883)
- Karl Moritz Schumann in Engler & K. Prantl (1895): Die Natürlichen Pflanzenfamilien III. 6 updated by W. Schultze-Motel in H. Melchior (1964): Adolf Engler's Syllabus der Pflanzenfamilien, 12th edition, II. Band.
- Wettstein (1901-1908)
- John Hutchinson (1926-1934)
- Arthur Cronquist (1968, 1981)
- Aaron Goldberg (1986)
- Takhtajan (1966, 1980)
- R.M.T.Dahlgren (1975)
Thus forming a solid consensus that was achieved mainly on the basis in morphological field.
Malvaceae is still accepted in its restricted sense in several nomenclatural compilations: at IK, APNI (Australian Plant Names Index) and GCI (Gray Card Index) at IPNI (see also list of systems of plant taxonomy); and in several herbaria of the whole world, besides being the classification "standard" of many reference works such as manuals, floras and very important: identification keys (see Thonner's analytical key to the families of flowering plants).
A different approach was taken by Edlin (1935), who restricted Malvaceae even further by transferring the genera with capsular fruits, including Gossypium and Hibiscus, into a more broadly defined Bombacaceae.
Malvaceae sensu stricto as traditionally defined consists of about 111-119 genera, totalling about 1,500 species. This includes the mallows, cotton plants, okra, hibiscus, and hollyhocks.
[edit] Genera
Source: Royal Botanic Gardens, Kew
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[edit] Malvaceae sensu lato
In the broader APG circumscription, the Malvaceae are also a cladistically monophyletic group but take in a much larger number of genera. Because molecular phylogenies have shown that Bombacaceae, Tiliaceae, and Sterculiaceae as traditionally defined are closely related to Malvaceae s.s. but are not monophyletic groups, Malvaceae have been expanded to include these families. This expanded definition has been adopted by numerous researchers on the Malvales (e.g., Baum et al. 2004, Perveen et al. 2004, Tate et al. 2005).
Whether a consensus in favor of a broad or narrow circumscription of Malvaceae will be adopted, or something in between, remains to be seen. The broad circumscription of Malvaceae has been adopted in textbooks on plant systematics (Judd et al. 1999), in a comprehensive treatment of vascular plant families and genera, the Kubitzki system, by Bayer & Kubitzki (2003), and in a treatment of Neotropical plant families by Maas & Westra (2005). The most recent version of the Thorne system takes an intermediate approach in combining Bombacaceae and Sterculiaceae under Malvaceae, but retaining Byttneriaceae (containing elements of the traditional Sterculiaceae and Tiliaceae) and a considerably restricted Tiliaceae as separate families.
Malvaceae sensu APG is a family of about 250 genera; it thus also includes lindens, kapok, baobabs, balsa, etc. There are nine subfamilies (Bayer et al. 1999, Bayer & Kubitzki 2003):
- Bombacoideae, traditionally in Bombacaceae
- Brownlowioideae, traditionally in Tiliaceae
- Byttnerioideae, traditionally in Sterculiaceae
- Dombeyoideae, traditionally in Sterculiaceae
- Grewioideae, traditionally in Tiliaceae
- Helicteroideae, traditionally in Sterculiaceae (tribe Helictereae) and Bombacaceae (tribe Durioneae)
- Malvoideae, traditionally Malvaceae sensu stricto
- Sterculioideae, traditionally in Sterculiaceae
- Tilioideae, traditionally in Tiliaceae
- Selected genera
- Abelmoschus - Okra
- Abutilon - Abutilon
- Abutilothamnus
- Adansonia – Baobab traditionally in family Bombacaceae
- Alcea - Hollyhock
- Althaea - Marsh mallow
- Argyrodendron - Booyong - traditionally in family Sterculiaceae
- Bombax – Silk-cotton tree traditionally in family Bombacaceae
- Brachychiton – Bottletree traditionally in family Sterculiaceae
- Callirhoe - Poppy mallow
- Ceiba – Kapok traditionally in family Bombacaceae
- Chiranthodendron – Mexican Hand Tree traditionally in family Sterculiaceae
- Cola - Kola nut traditionally in family Sterculiaceae
- Commersonia - Brown Kurrajong traditionally in family Sterculiaceae
- Corchorus - Jute traditionally in family Tiliaceae
- Durio – Durian traditionally in family Bombacaceae
- Fremontodendron – Flannelbush traditionally in family Sterculiaceae
- Gaya – Gaya
- Gossypium - Cotton plant
- Hibiscus - Hibiscus
- Hoheria – Lacebark
- Kosteletzkya - Saltmarsh mallow
- Lavatera - Tree mallow or Rose mallow
- Malva - Mallow
- Malvaviscus - Turk's cap mallow
- Ochroma – Balsa traditionally in family Bombacaceae
- Sida
- Sidalcea - Greek mallow
- Sphaeralcea - Globemallow
- Sterculia - traditionally in family Sterculiaceae
- Theobroma - Cacao traditionally in family Sterculiaceae
- Thespesia
- Tilia – Linden, traditionally in family Tiliaceae
- Urena
[edit] References
- Baum, D. A., W. S. Alverson, and R. Nyffeler (1998). "A durian by any other name: taxonomy and nomenclature of the core Malvales". Harvard Papers in Botany 3: 315–330.
- Baum, D. A., S. D. Smith2, A. Yen, W. S. Alverson, R. Nyffeler, B. A. Whitlock and R. L. Oldham (2004). "Phylogenetic relationships of Malvatheca (Bombacoideae and Malvoideae; Malvaceae sensu lato) as inferred from plastid DNA sequences". American Journal of Botany 91: 1863-1871. (abstract online here).
- Bayer, C., J. R. Hoppe, K. Kubitzki, M. F. Fay, A. Y. De Bruijn, V. Savolainen, C. M. Morton, K. Kubitzki, W. S. Alverson, and M. W. Chase (1999). "Support for an expanded family concept of Malvaceae within a recircumscribed order Malvales: a combined analysis of plastid atpB and rbcL DNA sequences". Botanical Journal of the Linnean Society 129: 267–303.
- Bayer, C. and K. Kubitzki 2003. Malvaceae, pp. 225-311. In K. Kubitzki (ed.), The Families and Genera of Vascular Plants, vol. 5, Malvales, Capparales and non-betalain Caryophyllales.
- Edlin, H. L. (1935). "A critical revision of certain taxonomic groups of the Malvales". New Phytologist (1-20): 122-143.
- Judd, W. S., and S. R. Manchester (1997). "Circumscription of Malvaceae (Malvales) as determined by a preliminary cladistic analysis of morphological, anatomical, palynological, and chemical characters". Brittonia 49: 384–405.
- Judd, W. S., C. S. Campbell, E. A. Kellogg and P. F. Stevens. Plant Systematics: A Phylogenetic Approach.
- Maas, P. J. M. and L. Y. Th. Westra. 2005. Neotropical Plant Families (3rd edition).
- Perveen, A., E. Grafström and G. El-Ghazaly (2004). "World Pollen and Spore Flora 23. Malvaceae Adams. P.p. Subfamilies: Grewioideae, Tilioideae, Brownlowioideae". Grana 43: 129-155. (abstract online here).
- Tate, J. A., J. F. Aguilar, S. J. Wagstaff, J. C. La Duke5, T. A. Bodo Slotta and B. B. Simpson (2005). "Phylogenetic relationships within the tribe Malveae (Malvaceae, subfamily Malvoideae) as inferred from ITS sequence data". American Journal of Botany 92: 584-602. (abstract online here).
[edit] External links
- Alverson, William S., Barbara A. Whitlock, Reto Nyffeler, Clemens Bayer and David A. Baum. 1999. Phylogeny of the core Malvales: evidence from ndhF sequence data. American Journal of Botany 86: 1474-1486.
- Core Malvales from Tree of Life
- Malvaceae: plants of Hawaii (image gallery) from HEAR
Malvaceae sensu lato:
- Malvaceae Info, includes much recent taxonomic discussion and a full list of about 250 genera; also numerous photos
Malvaceae sensu stricto:
- Malvaceae in L. Watson and M.J. Dallwitz (1992 onwards). The families of flowering plants: descriptions, illustrations, identification, information retrieval. http://delta-intkey.com
- Malvaceae – miscellaneous photographs at University of Hawaii Botany site.
- Royal Botanic Gardens, Kew list of genera
