372 The Ohio Naturalist. [Vol. V, No. 8, 



117. Leaves serrate, crenate, dentate or variously lobed. 120. 



lis. Evergreen shrubs parasitic on trees; leaves small. Phoradendron. 



118. Trees with large leaves. 119. 



119. Pith diaphragmed, or with large cavities; petioles usually hollow; 



axillary buds superposed. Paulownia. 



119. Pith and petioles solid; axillary buds not superposed. Catalpa. 



120. Leaves more or less lobed. 121. 



120. Leaves not lobed. 122. 



121. Leaves without stipules, or if with stipules then large trees with 



very large-toothed or angled but not serrate leaves; fruit a 

 2-winged samara. Acer. 



121. Leaves with stipules, some with glands on the petiole or if not then 



always serrate-dentate; shrubs; fruit a drupe. Viburnum. 



122. Stipules none; axillary buds minute, covered; fruit a capsule. 



Philadelphus. 



122. Stipules or stipular scars present; fruit a drupe. Rhamnus. 



—123— 



123. Leaves serrate, dentate, crenate, or variouslv lobed. 124. 



123. Leaves entire. 1*32. 



124. Twigs with a prominent pubescent ridge decurrent from the middle 



of the line connecting the petiole bases. Diervilla. 



124. No pubescent decurrent ridge from the middle of the connecting 



line, but the ends of the petiole bases may be decurrent. 125. 



125. Leaves evergreen, on wood of the previous season, obovate or 



obicular; creeping shrubs without stipules. Linnaea. 



125. Leaves not evergreen. 126. 



126. Bark of ripe twigs green, bundle scar or vascular bundle in base of 



petiole 1 ; pith rhombic. Euonymus. 



126. Bark of ripe twigs gray, brown, or red; pith cylindrical or nearlv so. 



'127. 



127. Stipules or stipular scars present. 12S. 



127. Stipules none. 129. 



128. Lateral veins 3 or 4 pairs, the outer more or less parallel with the 



midrib; usually with terminal thorns. Rhamnus. 



128. Lateral veins 5 or more pairs, the outer not parallel with the midrib 



but spreading; without thorns. Viburnum. 



129. Petioles of the lower leaves as long or nearlv as long as the large 



blades. 130. 



129. Petioles short. 131. 



130. Leaves dentate, outer bark separating readily from the green inner 



bark. Hydrangea. 



130. Leaves serrate or serrate-dentate, outer bark not spreading readily. 



Viburnum. 



131. Low shrubs; leaves normally entire, occasionally irregularly luothed 



or somewhat lobed, usually of the ovate or oval type. 



Symphoricarpos. 

 131 Erect shrubs, leaves serrate or dentate; axillary buds nii!uUe rov- 

 ered by the petiole base; twigs minutely angled or striate. 



Philadelphus. 



131. Erect shrubs or small trees; leaves dentate or serrate; axillary buds 



evident, not covered by the petiole base. Viburnum. 



132. Twigs and leaves white- or brown-scurfy or stellate-pubescent. 



Lepargyraea. 



132. Not scurfy or stellate-pubescent. 133. 



133. Leaves pellucid-punctate or black-dotted; low shrubs. 134. 



133. Leaves not pellucid-punctate or black-dotted. b^.'i. 



134. Creeping shrubs; leaves 2-glandular at the l;ase. Ascyrum. 

 134. Erect shrubs; leaves not 2-glandular at the base. Hypericum. 



