Flora of North America species comparison

In the southern third of Texas, and in adjacent Louisiana, New Mexico, and Mexico, heads of Liatris punctata tend to be more widely spaced than characteristic for the species over the rest of its range. The most distinctive plants are in trans-Pecos Texas (and Mexico), and they occur at higher elevations than those in the more eastern range. Corms usually are elongate or rhizomiform; Gaiser described L. mucronata var. interrupta from a variant with subglobose corms. Intergrades in head congestion also are encountered, even northward into the Texas panhandle, and the variety is not sharply delimited. The populations with widely separated heads probably were ancestral to L. bracteata and L. cymosa, as well as a race (yet unnamed) with piloso-hirsutulous leaves, which occurs on the Edwards Plateau.

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

Gaiser distinguished var. punctata (type from Saskatchewan) from var. nebraskana by its thicker, often shorter stems, broader and shorter leaves, leaves and phyllaries with ciliate margins, and phyllaries with lanceolate-acuminate apices. Weak geographic trends exist in these features; variability renders var. nebraskana largely typological and necessitates much arbitrary identification. B. R. Menhusen (1963) also did not find justification for recognizing var. nebraskana. Variation in chromosome number may be associated with some of the apparent polymorphism.

Liatris densispicata was described from sand dunes in Minnesota. It was said to have “an elongate rootstock that runs horizontally in the sand, giving off clusters of aerial stems,” and to differ from L. punctata by “the generally finer and more slender structure of the stem, spike, and leaves” (L. O. Gaiser 1946, p. 363). It was listed as a synonym of L. punctata by G. B. Ownbey and T. Morley (1991).

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