Flora of North America species comparison

Species 400–600 (37 in the flora).

E. Hultén (1968) listed three Pedicularis taxa in his Flora of Alaska and Neighboring Territories that do not occur in the flora area; P. amoena Adams ex Steven, P. kanei Durand subsp. adamsii (Hultén) Hultén, and P. villosa Ledebour ex Sprengel are found on the Chukchi Peninsula of Siberia.

The most common chromosome number for Pedicularis is 2n = 16. Two species are reported to have a diploid number of 2n = 12, and at least five species have a number of 2n = 14. See reviews in Jie C. et al. (2004) and M. I. S. Saggoo and D. K. Srivastava (2009).

Infrageneric classification of Pedicularis is both difficult and incomplete. The author has not attempted to present one for the North American taxa. Inconsistencies result from using either floral morphology or phyllotaxy to construct major subgeneric groups (C. Steven 1823; G. Bentham 1835; C. J. Maximowicz 1888; D. Prain 1890; G. Bonati 1918; Tsoong P. C. 1955); the latter author proposed 130 series to accommodate the worldwide variation in Pedicularis. Recognizing that floral form probably evolved in parallel among groups, Li H. L. (1948) employed phyllotaxy to erect three informal subgeneric taxa (greges) for the Pedicularis of China, including grex Allophyllum, species with alternate leaves; grex Cyclophyllum, species with opposite or verticillate arrangement of leaves; and grex Poecilophyllum, species with alternate to subopposite leaves on the same plant. However, molecular phylogenies (Yang F. S. et al. 2003; R. H. Ree 2005; B. W. Robart et al. 2015; Yu W. B. et al. 2015) indicate inconsistencies even in the treatment by Li, although the study by Yu et al., which included 257 species, did show that grex Cyclophyllum is monophyletic.

Pediculariopsis was described to account for species (for example, Pedicularis verticillata) that exhibit a different base chromosome number (x = 6 versus x = 8). That concept has not been accepted by others, because there is little morphological support.

The use of infraspecific ranks in Pedicularis follows T. F. Stuessy (1990), who argued that the subspecific rank is appropriate when several obvious morphological differences are associated with an allopatric or peripatric geographical pattern, whereas the varietal rank is appropriate when one to few differences are associated with more or less geographic overlap. Unfortunately, Pedicularis specialists have not used these levels consistently. The subspecies rank is used here, except in P. bracteosa, P. centranthera, and P. contorta.

Pedicularis is a common element of arctic and alpine habitats in the Northern Hemisphere, with the greatest concentration of species occurring in Asia.

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