Glandularia J.F. Gmel.
Glandularia is a genus of ca. 50-100 species, centered in South America, Mexico and the southwestern United States. Some species are grown for ornament (incl. “garden verbena”) two of which have been recorded as ephemeral escapes in Belgium. According to Wann (2000) at least five further species of Glandularia are cultivated as ornamentals in Europe.
The generic status of Glandularia is increasingly accepted (Sanders 2001, O’Leary & al. 2007, Mabberley 2008). In addition to morphological features Glandularia and Verbena are also cytologically distinct (Schnack & Covas 1944).
1. Corolla tube ca. twice as long as calyx. Leaves undivided, coarsely serrate at margin. Flowers ca. 15-25 mm across === Glandularia xhybrida
1. Corolla tube slightly longer than to ca. twice as long as calyx. Leaves bipinnatifid. Flowers ca. 10 mm across === G. aristigera
Literature
Jäger E.J., Ebel F., Hanelt P. & Müller G. (eds.) (2008) Rothmaler Band 5. Exkursionsflora von Deutschland. Krautige Zier- und Nutzpflanzen. Springer Verlag, Berlin: 880 p.
Mabberley D.J. (2008) Mabberley’s plant-book (3th ed.). Cambridge University Press, Cambridge: XVIII + 1021 p.
Moldenke H.N. (1961) Materials towards a monograph of the genus Verbena. Phytologia 8: 108-496.
O’Leary N., Múlgura M.E. & Morrone O. (2007b) New Combinations in South American Glandularia (Verbenaceae). Novon 17(4): 503-511. [available online at: https://www.researchgate.net/publication/232689180_New_Combinations_in_S...
O'Leary N., Peralta P. & Múlgura M.E. (2013) El género Glandularia (Verbenaceae) en Chile. Darwiniana N.S. 1(2): 253-278. [available online at: http://www.ojs.darwin.edu.ar/index.php/darwiniana/article/view/527/560]
O'Leary N. & Thode V. (2016) The Genus Glandularia (Verbenaceae) in Brazil. Annals of the Missouri Botanical Garden 101(4): 699-749. [available online at: https://www.researchgate.net/publication/311483713_The_Genus_Glandularia...
Peralta P.F. & Múlgura M.E. (2011) El género Glandularia (Verbenaceae) en Argentina. Ann. Missouri Bot. Gard. 98(3): 358-412.
Pruski J.F. & Nesom G.L. (1992) Glandularia x hybrida (Verbenaceae), a new combination for a common horticultural plant. Brittonia 44: 494-496.
Sanders R.W. (2001) The genera of Verbenaceae in the Southeastern United States. Harvard Papers Bot. 5(2): 303-358.
Schnack B. & Covas G. (1944) Nota sobre la validez del género Glandularia (Verbenáceas). Darwiniana 6: 469-476.
Turner B.L. (1998) Texas species of Glandularia (Verbenaceae). Lundellia 1: 3-16.
Turner B.L. (1999) A reevaluation of the Mexican species of Glandularia (Verbenaceae). Lundellia 2: 55-71.
Umber R.E. (1979) The genus Glandularia (Verbenaceae) in North America. Syst. Bot. 4: 72-102.
Wann J.D. (2000) Verbena. In: Cullen J. & al. (eds.), The European Garden Flora, vol. 6. Cambridge University Press, Cambridge: 151-153.