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



KEY TO THE GENERA OF OHIO WOODY PLANTS BASED ON 

 LEAF AND TWIG CHARACTERS. 



John H. Schaffner. 



1. Foliage leaves with expanded blades, netted-veined. 8. 



1. Foliage leaves needle-shaped, narrowlj' linear, subulate, or scale- 

 like; conifers, or in one case a dicotyl with delicate twigs and 

 minute leaves. 2, 



1. Foliage leaves fan-shaped with dichotomous venation, a number on 



thick, wart-like, persistent dwarf branches. Ginkgo. 



2. With typical dwarf branches, persistent for more than 1 year, 3. 

 2. With feather-like dwarf branches, deciduous each year, the linear 



leaves spreading into 2 ranks. Taxodium. 

 2. With delicate sprajMikc twigs deciduous each year; leaves scale- 

 like, minute; a dicotyl. Tamarix. 



2. Without dwarf branches. 4. 



3. Dwarf branches small, self-pruned, with 2-5 foliage leaves. Pinus. 



3. Dwarf branches thick, wart-like, persistent, with numerous decid- 



uovis leaves. Larix. 



4. Leaf buds scaly; leaves scattered. 5. 



4. Leaf buds not scaly, naked; leaves opposite or whorled. 7. 



5. Leaf scar on a sterigma, the twigs covered with scales representing 



the leaf bases. 6. 



5. Leaf scar on the bark; twigs without scales; leaves flat. Abies. 



6. Leaves flat, those on the upper side of the twig much shorter than 



the lateral ones; trees. Tsuga. 



G. Leaves flat all of about the same length; ours a shrub. Taxus. 



G. Leaves more or less 4-sided, spreading in all directions. Picea. 



7. Foliage leaves small, scale-like, appressed, opposite, 4-ranked, 



closely covering the twigs which are decidedly flattened and fan- 

 like; leaves of two shapes, the dorsal and ventral broader and 

 less acute than the lateral ones; scales of the carpellate cone not 

 peltate. Thuia. 

 7. Foliage leaves small, scale-like, appressed, opposite, 4-ranked, 

 closely covering the slightly flattened twigs which are not very 

 fan-like; leaves nearly or quite similar; scales of the carpellate 

 cone peltate. Chamaecyparis. 



7. Foliage leaves of two types, scale-like and subulate, opposite or in 



threes; the scale-like leaves 4-ranked, appressed, causing the 

 twigs to appear quadrangular, the subulate leaves spreading; 

 one or both types of leaves on a plant ; carpellate cone developing 

 into a bluish-black berry-like fruit. Juniperus. 



— 8— 



8. Leaves alternate. 9. 



8. Leaves opposite or whorled. 110. 



9. Leaves simple. 10. 



9. Leaves compound. 93. 

 10. Leaves pinnately veined or with a siinple midrib. 11. 



10. Leaves palmately veined or at least with 2 or more prominent side 



ribs coming from near the base of the blade. 74. 



11. Leaves not revolute-inargined when fully expanded. 12. 



11. Leaves decidedly rcvolute-margined, evergreen, thus appearing on 



wood of the previous season. 90. 



12. Leaves truncate or broadly emarginate; witli complete stipular 



rings at the nodes. Liriodendron. 

 12. Leaves entire. 13. 



