Feb., 1905.] Key— Ohio Woody Plants. 277 



KEY TO THE GENERA OF OHIO WOODY PLANTS IN THE 



WINTER CONDITION. 



John H. Schaffxer. 



The writer has been studying the winter condition of trees 

 and shrubs for the past two years, having been attracted to the 

 subject through observations on self -pruning. Many of the twig 

 characters are exceedingly important and should be given more 

 consideration in specific descriptions and in manuals. Inci- 

 dentally some keys were constructed. These have been verified 

 to a large extent by use in the class room and it is believed that 

 a twig key can be used with as little difficulty as one based on 

 the usual floral characters. A hand lens is necessary to deter- 

 mine some of the characters included. 



1. Foliage leaves persistent and usually evergreen. 2. 



1. Foliage leaves deciduous each year. 20. 



2. Foliage leaves needle-shaped, subulate, narrowly linear, or scale- 



like; conifers. 3. 



2. Foliage leaves with expanded blades, netted veined. 8. 



3. With dwarf branches, each bearing 2-5 foliage leaves. PINUS. 



3. Without true dwarf branches. 4. 



4. Leaf buds scaly. 5. 



4. Leaf buds not scaly, naked. 7. 



5. Leaf scar not on a sterigma, prominent, circular; leaves flat. ABIES 

 5. Leaf scar on a sterigma, the base of the leaf remaining as a scale on 



the twig. 6. 



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

 the lateral ones. TSUGA. 



G. Leaves flat, all of about the same length. TAXUS. 



0. Leaves more or less 4-sided, spreading in all directions. PICE A. 



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. THUJA. 



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

 closely covering the slightly flattened twigs which arc not very 

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

 cone peltate. CHAM^CYPARIS. 



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 with spines or reduced to spines. 9. 



8. Leaves without spines. 10. 



9. Leaves compound, with spine-tipped teeth; or leaves of the main 



twigs usually without a blade and reduced to 1-5 prong-like 



spines, at length dry. BERBERIS. 

 9. Leaves simple, with spine-tipped teeth or lobes; twigs grey. ILEX. 

 10. Leaves opposite or whorled. 11. 

 10. Leaves alternate. 13. 



