[link|http://www.fw.vt.edu/dendro/dendrology/factsheets.cfm|Dendrology at Virginia Tech]. It helped me to finally identify the [link|http://www.fw.vt.edu/dendro/dendrology/syllabus/factsheet.cfm?ID=75|Willow Oaks] that are fairly common around here. They're beautiful large trees when mature, but the leaves are a pain to rake because they're so narrow.
Cheers,
Scott.