1. Leaflets 5-9, the terminal one distinctly larger than those of lowest pair; pith of year-old twigs continuous; staminate aments peduncled in groups of 3.

Carya

1. Leaflets (9-) 11-19, the terminal one usually about equal to those of lowest pair, or smaller; pith of year-old twigs becoming chambered (separating into thin plates and cavities); staminate aments sessile or nearly so.

Juglans