116 Proceedings of the Ohio State Academy of Science 



CLASSIFICATION AND DESCRIPTION OF THE 

 SPECIES. 



SERIES III. SPERMATOPHYTA. SEED-PLANTS. 



Subkingdom, GYMNOSPERMAE. Gymnosperms. 



Class, GiNKGOEAE. 



Order, Ginkgoales. 



Ginkgoaceae. Ginkgo Family. 



I. Ginkgo Kaempf. Ginkgo. 



Trees with deciduous, fan-shaped, dichotomously veined 

 leaves on wart-like dwarf branches. 



* Ginkgo biloba. L. Maiden-hair-tree. A large, beauti- 

 ful and hardy tree with dioecious flowers. Seed large, drupe- 

 like. Autumn leaves orange. Introduced from China and 

 Japan ; should be commonly cultivated for ornament. 

 Class, CoNiFERAE. Conifcrs. 

 Order, Pinales. 



Pinaceae. Pine Family. 



2. Pinus L. Pine. 



Resinous evergreen trees with small dwarf branches bearing 

 2-5 narrow foliage leaves ; dwarf branches and ordinary twigs 

 covered with scale leaves. Dwarf branches self -pruned after a 

 number of years. Carpellate cones woody, with numerous car- 

 pels. Our most important lumber trees. 



Dwarf branches with 5 foliage leaves ; ovuliferous scales little thick- 

 ened at the tip. P. strobus. 



Dwarf branches with '2-3 foliage leaves ; ovuliferous scales much 

 thickened at the tip. 2. 



Dwarf branches with 3 foliage leaves, rarely 2 or 4. 3. ' 



Dwarf branches mostly with 2 foliage leaves some of them may be 

 with 3. 4. 



Leaves 6-10 in. long; carpellate cone oblong-conic. P. taeda. 



Leaves 3-5 in. long ; carpellate cones ovoid. P. rigida. 



Twigs glaucous ; resin-ducts parenchymatous ; carpellate cones l|-3 

 in. long; ovuliferous scales tipped with a prickle or small spine. 5. 



Twigs not glaucous. 6. 



