2. Bundle-scars three. 

 a. Leaf-scars usually two-ranked. 



TJlmus (Elms) . Leaf-scars rather large, mostly semicircular. Buds 

 commonly of two sizes, rather large flower-buds and smaller leaf-buds. 

 Bud-scales smooth or hairy. 



Ostrya Virginioa (Hop-hornbeam). Leaf-scars small, semiellip- 

 tical. Buds mostly of about the same size. Bud-scales smooth. 



Carpinus Caroliniana (Hornbeam) . Leaf-scars very small, mostly 

 crescentic. Buds mostly of about the same size. Bud-scales hairy. 



b. Leaf-scars in more than two ranks. 



(1) Stipule-scars more or less distinct. 



(x) Twigs a/fmed with mostly branched thorns. 



Gleditschia triacanthos (Honey Locust). Buds depressed. 

 Leaf-scars three-lobed. Pith roundish, white. Wood yellow. 



(y) Twigs unarmed. Branchlets with corky ridges. 



laiquidambar Styraciflua (Sweet Gum Tree). Buds ovoid. 

 Leaf-scars semielliptical. Pith angled, brownish. Wood white. 



(z) Twigs una/rmed or merely thorny tipped. Branchlets without 

 corky ridges. 



Prunus (Plums, Cherries, Peach, etc.). Leaf-scars elliptical or 

 semielliptical. Pith roundish, brown or white. 



Pyrus (Apples, Pears, Quinces, ETC.). Leaf-scars crescentic. Pith 

 roundish, pale. 



Populus (Poplars). Leaf-scars three-lobed, semioval, semielliptical 

 or crescentic. Pith sharply five-angled, brown. 



Betllla (Birches). Leaf-scars elliptical, semielliptical, or semicir- 

 cular. Pith irregularly angled, pale. Staminate catkins much developed 

 in autumn. 



(2) Stipule-scars none. 



Wyssa (Tupelos). Terminal buds commonly largest. No catkins. 



3. Bundle-scar one, elongated. 



Sassafras ofiB,cinale (Sassafras). Leaf-scars small, blackened. 

 Twigs greenish, aromatic. Buds ovoid-globose. 



Prunus serotina (Wild Black Cherry). Leaf-scars small, light 

 colored. Twigs brownish, not aromatic. Buds, at least the end ones, 

 long-ovoid. 



