Flora of North America species comparison

Abies magnifica often exists in extensive high elevation stands in the Sierra Nevada; its close relative A. procera occurs in small mountaintop populations relatively isolated from one another. As expected for isolated populations, A. procera produces large interpopulation variation in morphology (J.Maze and W.H. Parker 1983) and chemistry (E.Zavarin et al. 1978). Where the two species meet in southern Oregon and northern California, many populations are intermediate; these have been called A. magnifica var. shastensis Lemmon. The status of such intermediates is unsettled. They may be accepted as hybrids between A. magnifica and A. procera (Liu T. S. 1971) or, alternatively, the paleontological record suggests that the two species may have originated from the intermediates (E.Zavarin et al. 1978). Individuals from this region should be assigned to A. magnifica, A. procera, or A. magnifica × procera (E.L. Parker 1963), depending on the morphologic criteria selected to differentiate the species, though clearly these individuals are genetically quite different from those near the type localities of the two species.

An extensive study of this variation, as proposed by E.Zavarin et al. (1978), is warranted. Such a study should consider data from the type localities as a basis of comparison. Moreover, to evaluate this situation critically, one should first determine if any genetic exchange occurs between Abies lasiocarpa and A. procera that may complicate an evaluation.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

The Pinaceae, with a fossil record extending back to the Cretaceous (C.N. Miller Jr. 1988), constitute a clearly defined natural taxon, the basic delimiting features of which are seen in the mature seed cones: bract-scale complexes consisting of well-developed scales that are free for most of their length from the subtending bracts, two inverted ovules on the adaxial face of each scale, and usually an obvious seed wing that develops from the cone scale. The 10 genera, too, are clearly defined.

The cones of certain members of the Pinaceae remain on the tree and closed for several to many years until a stimulus (often fire) causes them to open and shed their seeds. This condition, known as serotiny (adjective, serotinous), is seen in various pines (e.g., Pinus attenuata, P. banksiana, P. contorta).

This primarily Northern Hemisphere family extends south to the West Indies, Central America, Japan, China, Indonesia, the Himalayas, and North Africa. The family is dominant in the vegetation of large regions including, in the flora area, forests of the boreal and Pacific regions, of the western mountains, and of the southeastern coastal plain. Only one species of the family, Pinus merkusii, crosses the equator (in Sumatra).

Members of the Pinaceae are of major economic importance as producers of most of the world's softwood timber. Additionally, they are sources of pulpwood, naval stores (e.g., tar, pitch, turpentine, etc.), essential oils, and other forest products. All members of the family present in the flora, especially pines, are of varying importance to wildlife for food and cover. Many species, including most of the genera, are grown as ornamentals and shelter-belt trees and for revegetation. Most commonly seen in cultivation in the flora area are species of Abies, Cedrus, Larix, Picea, Pinus, Pseudotsuga, and Tsuga, each of these genera being represented by numerous cultivars. Keteleeria and Pseudolarix are mainly botanical garden subjects. Cathaya, the most recently described genus (1958), is apparently not yet in cultivation in North America.

Among the vegetative features useful for identification of some genera of Pinaceae are the leaf scars. These are best observed on those portions of living branchlets from which leaves have fallen.

Genera 10, species ca. 200 (6 genera, 66 species in the flora with 64 natives and 2 naturalized).

(Discussion copyrighted by Flora of North America; reprinted with permission.)