20 ILLINOIS NATURAL HISTORY SURVEY MANUAL 3 



n. Petioles and branchlets glandular- 

 pubescent Rubus, p. 105 



n. Without glandular pubescence. 



o. Leaves resinous-dotted beneath 



Ribes, p. 92 



o. Leaves without resinous dots 



Physocarpus, p. 99 



1. Leaves pinnately veined Crataegus, p. 134 



e. Leaf margins toothed but the blades not lobed. 

 p. Armed with spines or thorns. 



q. Glands present on the petiole near the 



blade Prunus, p. 139 



q. Petiole not bearing glands. 



r. Large, straight thorns on twigs and 



branches Crataegus, p. 134 



r. Small branched spines on twigs and 



branches Berberis, p. 81 



p. Not armed with spines or thorns. 



s. Twining vines Celastrus, p. 170 



s. Spreading or upright shrubs. 



t. Leaves clustered or in groups of 3 to 7 at 

 ends of branches. 

 u. Upright shrub; leaves oblong to ovate 



Azalea, p. 221 



u. Prostrate, creeping shrub; leaves ovate 



to nearly round Gaultheria, p, 226 



t. Leaves distributed along the twigs; upright 

 shrubs. 

 V. Leaves with 3 to 5 main veins. 



w. Low shrubs with glandular-serrate 



leaves Ceanothus, p. 181 



w. Tall shrubs with plainly serrate 



leaves Celtis, p. 69 



V. Leaves with 1 main vein. 



X. Buds inclosed by 1 scale Salix, p. 34 



X. Buds inclosed by 2 or more scales. 

 y. Lower leaf surface stellate- 

 pubescent Halesia, p. 240 



y. Leaves without stellate pubescence. 

 z. Small, dark glands on the midrib, 



above Aronia, p. 130 



z. Midrib glandless. 



1. Petiole gland-bearing near the 



blade Prunus, p. 139 



1. Petiole glandless. 

 2. Leaf base cordate or notched. 

 3. Teeth rounded and large, 



resembling scallops 



Hamamelis, p. 96 



3. Teeth sharp and fine. 



4. Leaves acute, entire mar- 

 gin serrate Corylus, p. 62 



