As to specific determinations, a little experience in the field discloses an amount of variation in species that does not always appear in the descriptions of authors; and species that are under the closest scrutiny of botanists, foresters or horticulturalists, attest by their multiple synonymy their wide variation. The possibilities of variation are indefinite and, with adaptable Pines, the range of variation is somewhat proportionate to change of climate. In mountainous countries, where there are warm sheltered valleys with rich soil below cold barren ledges, the most variable Pines are found. The western species of North America, for instance, are much more variable than the eastern species, while in Mexico, a tropical country with snow-capped mountains, the variation is greatest. Therefore in the limitation of species undue importance should not be given to characters responsive to environment, such as the dimensions of leaf or cone, the number of leaves in the fascicle, etc. Moreover, there are familiar examples (P. sylvestris, etc.) that show the possibility of wide differences in the cone of the same species. In the following classification species only are considered without attempting to determine varietal or other subspecific forms. But varieties are often mentioned as one of the factors illustrating the scope of species. Synonymy serves a like purpose, but synonyms not conveying useful information are omitted, Roezl's list of Mexican species, for instance, and variations in the orthography of specific names. PINUS 1755 Pinus Duhamel, Traité des Arbres, ii. 121. 1790 Apinus Necker, Elem. Bot. iii. 269. 1852 Cembra Opiz, Seznam, 27. 1854 Strobus Opiz, Lotos, iv. 94. 1903 Caryopitys Small, Fl. Southeast. U. S. 29. Leaves and shoots dimorphous, primary leaves on long shoots, secondary leaves on dwarf shoots. Flowers diclinous, the pistillate taking the place of long shoots, the staminate taking the place of dwarf shoots. Growth of wood and fruit emanating from the nodes; buds, branchlets and cones, therefore, in verticillate association. Leaves and staminate flowers in internodal position, the primary leaves along the whole length of the internode, subtending secondary leaf-fascicles on the apical, staminate flowers on the basal part. Buds compounded of minute buds in the axils of bud-scales, becoming the bracts of the spring-shoot. Branchlets of one or more internodes, each internode in three parts--a length without leaves, a length bearing leaves and a node of buds. Cone requiring two, rarely three years to mature, displaying its annual growths by distinct areas on each scale. Seeds wingless or winged, edible and nutritious.