Vinicius Castro Souza
Herbarium ESA - Escola Superior de Agricultura Luiz de Queiroz (ESALQ-USP), Brazil.
Annual, biennial or perennial herbs, less frequently small shrubs, indumentum of unicellular hairs often present. Leaves spirally arranged, simple, usually lobed or pinnatifid, with minute stipules. Inflorescences terminal, racemes or spikes, simple or compound. Flowers zygomorphic or almost actinomorphic, usually bisexual, rarely unisexual, hypogynous or rarely perigynous; sepals 4-6(-8), valvate or almost imbricate, petals (1-)2-6(-8) or absent, valvate, white or yellow, appendaged or not (Oligomeris Cambess.), connate or more frequently free and clawed, usually fringed; stamens (3-)16-22, rarely, more base of filaments surrounded by disc (except Oligomeris) and fused with them, anthers bithecate, introrse, opening by longitudinal slits; oary syncarpous or rarely apocarpous, with (2-)3-4(-7) carpels, superior, unilocular, with parietal placentation, ovules many by carpel, rarely only one. Fruits usually capsules, less frequently berry like or split into carpidia.
Notes on delimitation
- Resedaceae are currently divided in to six genera (Caylusea A.St.-Hil., Ochradenus Delile, Oligomeris Cambess., Randonia Coss., Reseda L. and Sesamoides Ortega), but Reseda is not monophyletic, unless it includes all the others, except Caylusea and Sesamoides (Martín-Bravo et al. 2007). The generic circumscription therefore needs revising.
- The family is included in Brassicales as a sister group to Gyrostemonaceae according to the APG III (2009).
Distribution in the Neotropics
- Resedaceae are centered on warm temperate subtropical areas, mainly around Mediterranean region, extending into tropics and the temperate zone. In the New World where only Oligomeris occurs species are found from South U.S.A. to North Mexico. The only native species (but see Martín-Bravo et al., 2009) in the Neotropics is Oligomeris linifolia (Vahl) J.F. Macbr., found in desert areas in Northern Mexico (Baja California, Chihuahua, Coahuila, Nuevo León, Sonora).
Distinguishing characters (always present)
- Many of the most common family characters in Resedaceae are absent in Oligomeris, the only genus in the Neotropics. So, although Resedaceae almost always have a conspicuous nectary and appendaged petals, they are absent in this genus.
- Other distinguishing characters include: leaves spirally arranged, simple; small stipules (sometimes not interpreted as stipules); racemose inflorescences; ovary superior, unilocular, with parietal placentation.
Other important characters
- Flowers zygomorphic, bisexual, hypogynous.
- Petals yellow, free, clawed and fringed.
- Ovary syncarpous.
- Ovules many per carpel.
- Fruit a capsule.
- Seeds arillate.
Number of genera
- One: Oligomeris Cambess .
- In addition to the native Oligomeris, Reseda odorataL. (garden mignonette), probably native in the North Africa, is cultivated in Neotropics as an ornamental.
Angiosperm Phylogeny Group (APG) 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: 105-121.Kubitzki, K. 1998. Resedaceae. In: K. Kubitzki, & C. Bayer (eds.). The Families and Genera of Vascular Plants, vol. V, Dicotyledons; Malvales, Capparales, and non-betalain Caryophyllales, pp. 334-338. Springer-Verlag, Berlin.
Martín-Bravo, S., Meimberg, H., Luceño, M., Märkl, W., Valcárcel, V., Bräuchler, C., Vargas, P., Heubl, G. 2007. Molecular systematics and biogeography of Resedaceae based on ITS and trnL-F sequences. Molecular Phylogenetics and Evolution 44: 1105-1120.
Martín-Bravo, S., Vargas, P., Luceño, M. 2009. Is Oligomeris (Resedaceae) indigenous to North America? Molecular evidence for a natural colonization from the Old World. Am. J. Bot. 96(2): 507-518.
How to cite
Souza, V.C. (2013). Neotropical Resedaceae. In: Milliken, W., Klitgård, B. & Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://www.kew.org/science/tropamerica/neotropikey/families/Resedaceae.htm.