The experimental taxonomy of Jasione montana L
The variation pattern of a range of natural populations of Jasione montana L. in Britain was studied. Morphological analysis revealed three distinct groups of individuals. These groups were given varietal status. The varieties are (a) Jasione montana var littoralis Fr., plants of which are decumbent, low growing, much branched and small flowered. (b) Jasione montana var latifolia Pugs. plants of which are robust with large, broad leaves, large flowering heads and large bracts. (c) Jasione montana L. var montana - plants of which are less robust than J. montana var latifolia, are upright with relatively narrow leaves and small flowering heads. Individuals of a variety generally grow together forming natural populations, though they are not located in any specific geographical area or according to any specific geographic pattern. The three varieties maintain their morphological distinctions when grown under controlled environmental conditions. Jasione montana var montana. the most abundant and widespread variety, exhibits a geographically correlated pattern of variation. Brebissons dwarf variety, Jasione montana var maritima found along the North Cornish coast was shown to be an environmentally dwarfed form of J. montana var montana. This taxon does not warrant taxonomic recognition. J. montana is to some extent self fertile but interplant and interpopulation crosses have greatly increased seed set. Intergroup crosses did not show any particular sterility barriers to exist between the three varieties. British plants of J. montana have a chromosome number of n = 6. One (or two) chromosomes were found to occur in J. montana var littoralis populations at a frequency of about one in three plants. Chiasma frequency per bivalent was approximately 1.34. This low frequency and the large percentage of terminalised chiasmata found will tend to minimise genetic variability on outcrossing. Flavonoids of the flowers of J. montana were shown to be relatively uniform in both type and frequency of occurrence. The principal anthocyanidin present in the flowers of J. montana is delphinidin. Herbarium and literature studies suggested that two additional varieties occur on the Continent. These varieties are J. montana var echinata Willk. Lange and Jasione montana var bracteosa Willk. Plants of J. montana var echinata are distinguished by their very deeply toothed long narrow bracts and their white colour (which is due to a coating of hairs). Plants of J. montana var bracteosa are distinguished by their sessile flowers, long ciliate hairs on their calyx teeth, undulate leaves and large bracts. Based on life form and geographical distribution there seem to be four main evolutionary lines in the genus. They are that characterised by Jasione crispa centered on Spain, that characterised by J. laevis centered on the Balkans and those of J. montana and J. foliosa.