Panarctic Flora

8102 Castilleja Mutis ex L. f.

• L. f., Suppl. Pl.: 47 (1782).

Notes: Rebristaya: Castilleja is a mainly North American genus of about 250 species of which comparatively few enter the Arctic. The genus is more diverse in the arctic Eurasian sector to where it seems to have reached via the emerged shelf during glacial periods. It is one of the most taxonomically complicated genera of the family. The C. pallida group species 02-07 is the most controversial. The base number is x = 12. Polyploidy (4x, 6x, 8x, 12x) is rather common. Hybridization is also recorded which results in significant variation of characters.

Elven and Murray: Rebristaya (1964a) is a basic treatment of the Eurasian species. We are skeptical to the larger number of species and subspecies proposed from the arctic parts of Eurasia compared to the arctic parts of North America. This genus is notoriously polymorphic, often even within populations. This polymorphism may have been treated in different ways taxonomically in Russian and American traditions. There is a lack of thorough trans-Beringian comparison, partly because Castillejas are difficult to examine as they loose many characters in herbarium specimens. However, we have no well-founded alternative and follow Rebristaya's proposals with some small modifications and comments.

Some North American authors have argued for several northern representatives as varieties of C. pallida (L.) Spreng. (e.g., Pennell 1934; Boivin 1952; Egger 2008). Both we and Rebristaya are skeptical to this approach. Firstly, varietal rank may not be the most appropriate one for taxa differing in several characters and geographically parapatric or sympatric. Secondly, we have seen few obvious intermediates where these proposed varieties co-occur in arctic and near-arctic sites. Varietal treatment may complicate nomenclature without any clear benefits in this case. However, we treat the relevant taxa as a C. pallida aggregate, following the circumscription of C. pallida s. lat. by Egger (2008).

• 
  ''Castilleja angustifolia'' in Red Rock Canyon, Spring Mountains, southern Nevada
  Source: Stan Shebs at Wikispecies