often long-pointed, thick shelled; branchlets pubescent. 9. C. alba (A, C). Branchlets slender; leaves 5—7-foliolate; involucre of the fruit tardily dehiscent to the middle, indehiscent or opening freely to the base; shell of the nut thick, bark close, (sometimes scaly in 13). Branchlets and leaves not covered when they first appear with rusty brown pubescence. Involucre of the fruit 3—5.5 mm. in thickness, opening freely to the base, leaves usually 7-foliolate; winter-buds pubescent. Leaflets hoary tomentose below in early spring, slightly pubescent at maturity; petioles and rachis glabrous; fruit broad-obovoid; branchlets glabrous. 10. C. leiodermis (C). Leaflets covered in early spring with silvery scales, pale and pubescent below during the season; petioles and rachis more or less thickly covered with fascicled hairs; fruit ellipsoidal to obovoid or globose; branchlets glabrous or slightly pubescent. 11. C. pallida (A, C). Involucre of the fruit 1—3 mm. in thickness; winter-buds glabrous or puberulous. Leaves 5, rarely 7-foliolate, glabrous or rarely slightly pubescent; fruit obovoid, often narrowed below into a stipitate base, the involucre indehiscent or tardily dehiscent. 12. C. glabra (A, C). Leaves generally 7-foliolate, glabrous or rarely pubescent; fruit ellipsoidal, subglobose or obovoid, the involucre opening freely to the base; bark often more or less scaly. 13. C. ovalis (A, C). Branchlets and leaves densely covered when they first appear with rusty brown pubescence; leaflets usually 5—7; winter-buds rusty pubescent. Fruit obovoid; the involucre 2—3 mm. in thickness; peduncles of the aments of staminate flowers often from the axils of leaves; branchlets soon becoming glabrous. 14. C. floridana (C). Fruit subglobose to broadly obovoid, ellipsoidal or pyriform, the involucre on the different varieties 2—13 mm. in thickness; branchlets pubescent through their first season. 15. C. Buckleyi (A, C). 1. Carya pecan Asch. & Gr. Pecan. [Illustration: Fig. 169]