Rosidae
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(′rōz·ə′dē)
(botany) A large subclass of the class Magnoliatae; most have a well-developed corolla with petals separate from each other, binucleate pollen, and ovules usually with two integuments.
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A former widely recognized subclass of Magnoliophyta (angiosperms or flowering plants). Deoxyribonucleic acid (DNA) and morphological studies have demonstrated that this group includes many more families than previously thought. Approximately 136 families (roughly 30% of the total angiosperms) in 11 orders are included in the rosids. With the asterids (often recognized as Asteridae), the rosids represent the two most advanced lines of dicots.
The primary distinguishing features of rosids are their diplostemenous flowers (anthers in two whorls, each whorl typically numbering the same as the perianth parts, although in some groups the number of stamens has increased) with unfused parts, except for the carpels (asterids have haplostemenous flowers with fused parts, typically with the stamens fused at least to the bases of the petals). Rosids have ovules with two integuments (that is, they are bitegmic, as opposed to the unitegmic asterids) and a several-layered nucellus (that is, they are crassinucellate, as opposed to the tenuinucellate asterids, which have a single-layered nucellus). There is nuclear endosperm formation (cellular in asterids), a reticulate pollen layer, mucilaginous leaf epidermis, and generally simple perforation vessel end-walls in the wood. The largest rosid orders are Malpighiales (16,100 species), Fabales (17,500), and Myrtales (10,600). See also Apiales; Celastrales; Cornales; Euphorbiales; Fabales; Geraniales; Haloragales; Linales; Magnoliopsida; Myrtales; Podostemales; Polygalales; Proteales; Rafflesiales; Rhizophorales; Rosales; Santalales; Sapindales.
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Rosidae
IN BRIEF: n. - A group of trees and shrubs and herbs mostly with polypetalous flowers.
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Rosidae
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It has been suggested that this article or section be merged with Rosids. (Discuss) Proposed since June 2011. |
Under the International Code of Botanical Nomenclature (ICBN), Rosidae is a botanical name at the rank of subclass. Circumscription of the subclass will vary with the taxonomic system being used; the only requirement being that it includes the family Rosaceae.
Under Phylocode, Rosidae is a clade defined as the most inclusive crown clade containing Rosa cinnamomea,[1] but not Berberidopsis corallina nor Dillenia indica nor Gunnera manicata nor Helianthus annuus nor Saxifraga mertensiana nor Stellaria media nor Viscum album. [2]
A well-known example of Rosidae as governed by the ICBN is in the Cronquist system. In the 1981, original, version of that system, the circumscription was as follows. [3]
- subclass Rosidae
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The Phylocode definition includes Crossosomatales, Geraniales, Myrtales, Fabidae (Celastrales, Cucurbitales, Fabales, Fagales, Huaceae, Oxalidales, Malpighiales, Rosales and Zygophyllales), Malvidae (Brassicales, Huerteales, Malvales, and Sapindales) as they are defined in the APG III system. [4] This definition was formulated in 2007, and is agnostic on the inclusion or exclusion of Picramniales and Vitales. [5] Since 2007, the phylogenetic positions of Picramniales and Vitales have been clarified. [6] The position of Picramniales as sister to Malvidae sensu stricto requires it to be included among the rosids. Vitales is sister to the clade of all that must be included in the rosids and its inclusion is optional. In APG III, it was included.
There is considerable overlap between the two definitions. Some apparent differences are the result of more broadly drawn orders in the second. Apiales, Cornales, Proteales and Santalales, and parts of Rafflesiales (sensu Cronquist) are excluded from the second, and many groups from Cronquist's Hamamelidae and Dillenidae are included.
In both senses, the term "rosid" applies, as an adjective and noun, to members of the group. In the APG III system, which eschewed formal botanical names between the ranks of class and order, the term "rosids" is used to define an informal clade corresponding to Rosidae as defined in the Phylocode.
References
- ^ sensu L. 1753 non L. 1759
- ^ Cantino, Philip D.; James A. Doyle, Sean W. Graham, Walter S. Judd, Richard G. Olmstead, Douglas E. Soltis, Pamela S. Soltis, & Michael J. Donoghue (2007). "Towards a phylogenetic nomenclature of Tracheophyta" (PDF). Taxon 56 (3): E1–E44. JSTOR 25065865. http://www.phylodiversity.net/donoghue/publications/MJD_papers/2007/164_Cantino_Taxon07.pdf.
- ^ Arthur John Cronquist. 1981. An Integrated System of Classification of Flowering Plants. Columbia University Press: New York, NY, USA.
- ^ Angiosperm Phylogeny Group (2009). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III". Botanical Journal of the Linnean Society 161 (2): 105–121. doi:10.1111/j.1095-8339.2009.00996.x. http://www3.interscience.wiley.com/journal/122630309/abstract.
- ^ Philip D. Cantino, James A. Doyle, Sean W. Graham, Walter S. Judd, Richard G. Olmstead, Douglas E. Soltis, Pamela S. Soltis, and Michael J. Donoghue. 2007. Electronic Supplement: pages E1-E44. To: Cantino et alii. 2007. "Towards a phylogenetic nomenclature of Tracheophyta". Taxon 56(3):822-846. (see External links below).
- ^ Hengchang Wang, Michael J. Moore, Pamela S. Soltis, Charles D. Bell, Samuel F. Brockington, Roolse Alexandre, Charles C. Davis, Maribeth Latvis, Steven R. Manchester, and Douglas E. Soltis (10 March 2009). "Rosid radiation and the rapid rise of angiosperm-dominated forests". Proceedings of the National Academy of Sciences 106 (10): 3853–3858. doi:10.1073/pnas.0813376106. PMC 2644257. PMID 19223592. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2644257
External links
- Rosidae at the TAMU Lab
- Electronic Supplement to Cantino et alii
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Mentioned in
Rosales
(botany)
Celastrales
(botany)
Cornales
(botany)
Euphorbiales
(botany)
Geraniales
(botany)
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