Panarctic Flora

810601 Rhinanthus minor L.

• L., Amoen. Acad. 3: 54 (1756). Type not designated (Jarvis 2007: 793).

2n= 14 14+8B (2x). - Europe (N, C), Canada, U.S.A. (NE), Greenland. - Numerous reports for "borealis", "groenlandicus", and "minor".
Witsch (1950) stated B-chromosomes to be a constant part of the genome of Rhinanthus (as Alectorolophus). The many reports of 2n = 22 then represent a set with 2n = 14 plus 8 B-chromosomes. Whether the northwestern North American plants reported with 2n = 14 represent plants without B-chromosomes, or plants where the B-chromosomes have not been counted, is not known. Taylor and Mulligan (1968), however, stated regular meiosis without B-chromosomes in 2n = 14 "borealis" from British Columbia. If so, the absence of B-chromosomes is a difference of Pacific vs. Atlantic (European) plants.

Geography: North American (N) - amphi-Atlantic - European.

Notes: The taxa of Rhinanthus are hemiparasites with an intricate morphological variation pattern partly treated and named as species or eco-geographical races, partly as seasonal races associated with land-use (see Gentianella). The R. minor group includes several such taxa treated as species (e.g., Hambler 1958; Soó and Webb 1972; Scoggan 1979; Ivanina 1980c; Hultén and Fries 1986; Hämet-Ahti et al. 1998) or subspecies (e.g., Stace 1997; Mossberg and Stenberg 2003; Elven et al. 2005). The morphological variation has not been analysed throughout the range. Currently applied taxonomical solutions are only local.

Three regional races have been proposed in Rhinanthus minor from the northern regions: subsp. minor, subsp. groenlandicus, and subsp. borealis. Whereas most authors consider subsp. minor to be mainly restricted to Europe (Böcher et al. 1978 an exception), the treatments of the two others are diverging. Hultén and Fries (1986) accepted subsp. groenlandica with a range from the Pacific eastwards across North America and Greenland to northwestern Europe. This approach has been the one of several North American authors, e.g., Scoggan (1979). Earlier, Hultén (1968a) accepted the Pacific plants as R. borealis and as apart from the Atlantic R. groenlandicus. In our opinion, Pacific R. borealis and Atlantic R. groenlandicus differ. The former is, e.g., small-flowered, often richly branched with first flowers at high nodes, and with leaves and bracts crenate-dentate, whereas the latter is large-flowered, mostly unbranched with first flowers at fairly low nodes, and with leaves and especially the enlarged bracts sharp-dentate. If races (or species) are recognized, these do not belong to the same one. The situation in Greenland is not clear. Böcher et al. (1978) recognized four taxa there: R. minor subsp. borealis, subsp. groenlandicus, and subsp. minor with var. minor and var. lapponicus. A division on three races is attempted below.

It is not clear whether one or both of the more southern seasonal races - the aestival subsp. minor or the autumnal subsp. stenophyllus (Schur) O. Schwarz - reach the Arctic.

• 
  
  Source: XN at Wikispecies