Showy phlox (Phlox speciosa): COSEWIC assessment and status report: chapter 9

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Special Significance of the Species

Canadian populations of Phlox speciosa occur at the northern extent of their geographic range. Although so-called “peripheral” populations have often been assigned low priority for conservation, the importance of populations at the edges of their ranges is increasingly being recognized.

At one time it was assumed that when a species becomes endangered, its geographical range would contract inwards, with the core populations persisting the longest. Recent work has shown that the opposite is often the case: species often persist along the periphery of their original ranges. This is because range contraction is strongly influenced by anthropogenic forces of extinction, in spite of historical patterns of species density (Channell and Lomolino 2000).

In addition, peripheral populations are often genetically distinct from populations from the centre of the taxon’s range (Lesica and Allendorf 1995). Protection of the genetic diversity of the taxon would therefore require the protection of the peripheral populations. No specific genetic information of this sort is, however, available for Phlox speciosa.

Finally, as its common name suggests, Phlox speciosa is a very showy and attractive plant. Phlox speciosa has a visual appeal that is valued by the general public. The species has been used as a horticultural plant in appropriate North American climates.

Phlox speciosa is similar in appearance to the more common species Phlox longifolia, which differs somewhat in habitat and in floral characters that require careful inspection.