1. Mid-stem leaves petioled (petioles winged in N. tabacum); flowers in a paniculate inflorescence.
2. Primary leaves with petioles wingless, not decurrent on the stem; tube of corolla ca. 10–20 mm long.
2. Primary leaves with petioles winged, ± decurrent on the stem; tube of corolla ca. 30–50 mm long
1. Mid-stem leaves sessile, ± clasping and short-decurrent; flowers in a racemose inflorescence
All species found in Nicotiana
MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. August 21, 2017. http://michiganflora.net/genus.aspx?id=Nicotiana.