June, 1905.] Key to the Genera of Ohio Woody Plants. 3^7 



42. Bark of trunk and larger branches separating into papery or 

 leathery sheets; trees or shrubs with glabrous, pubescent, or 

 glandular-warty twigs. Betula. 



42. Bark of trunk scaly, fine furrowed; twigs pubescent; carpellate 

 catkin in fruit appearing like that of the hop. Ostrya. 



42. Bark of trunk and larger branches smooth or rough, not scaly and 



fine furrowed and not separating into papery or leathery sheets ; 

 twigs coarsely glandular pubescent or nearly glabrous; fruit a 

 large nut in a leafy or partly coriaceous cixp or involucre. 



Corylus. 



—43— 



43. Leaves 2-ranked. 44. 



43. Leaves not 2-ranked. 45. 



44. Bark of trunk and larger branches separating into papery or leath- 



ery sheets; leaves doubly serrate, the lateral veins ending in the 

 main serrations, teeth or lobes. Betula. 

 44. Bark not in papery or leathery sheets; leaves not doubly serrate, 

 the lateral veins not ending directly in the serrations or teeth. 



Amelanchier. 



44. Bark not in papery or leathery sheets; leaves doubly serrate ending 



in the main serrations or lobes. Corylus. 



45. Leaves Avith spine-tipped teeth or lobes, or some of the leaves 



reduced to simple or branched spines. 46. 



45. Leaves not with spines. 47. 



46. Leaves evergreen, with spine-tipped lobes; trees. Ilex. 



46. Leaves reduced to simple or branched spines, some leaves without 



spines and deciduous each year; shrubs. Berberis. 



47. Pith solid but with prominent diaphragms, cylindrical; vascular 



bundles 3 in the base of the petiole; trees. Nyssa. 



47. Pith not both diaphragmed and solid. 48. 



48. Leaves with 1 or more disc-like, wart-like, or tooth-like glands on 



the petiole or at the base of the blade, or with tooth-like glands on 

 top of the midrib. 49. 



48. Leaves not with distinct glands on the top of the petiole or midrib, 



or at the base of the blade, but they may be glandular-hairy or 

 glandular-dotted. 53. 



49. Pith .5-angled, leaves usually more or less deltoid with gland-tipped 



teeth. Populus. 



49. Pith cylindrical or nearly so. 50. 



50. With typical lateral thorns. Crataegus. 



50. Not Avith typical lateral thorns, but some may have thorn-like 



stunted branches. 51. 



51. With tooth-like glands along the top of the midrib; shrubs. Aronia. 

 51. Glands tooth-like, mostly at the base of the midrib; leaves glabrous 



when mature, with long petioles; fruit a pome. Pyrus. 



51. Glands only on the petiole or near the base of the blade. 52. 



52. Glands tooth-like or rounded, or the leaf with gland-tipped teeth, 



but not with 2-4 large disc-like glands at the base on the edges 



of the blade; terminal bud absent when the twig is mature; 



twigs with brittle zones; fruit a capsule, in catkins. Salix. 

 52. Twigs green, red, or red and green; nectar glands disc-like, visually 



2-4 near the base at the edge of the blade; terminal bud present; 



twigs Avithout brittle zones; fruit a A^eh^ety drupe. Amygdalus. 

 52. Glands A^arious; tA\-igs not red and green, some with cleavage planes 



in basal joints but not AA'ith brittle zones; terminal bud present 



or absent, fruit a smooth drupe. Prunus. 



