Gentianella

Tutin, T. G., Heywood, V. H., Burges, N. A., Moore, D. M., Valentine, D. H., Walters, S. M. & Webb, D. A., 1972, Flora Europaea. Volume 3. Diapensiacea to Myoporaceae, Cambridge: Cambridge University Press : 64

Sect. GENTiANELLA . Calyx-lobes 4-5, equal, or unequal. Corolla usually more than 1-5 cm, obconical or cylindrical, fimbriate in throat, 4- or 5-lobed, lobes erect or patent. Style absent. Capsule stipitate or sessile.

Throughout the section, variation in leaf-shape, number of internodes, density of branching, and ratio of leaf-length to internode-length show parallel variation. These characters are more or less correlated with flowering time, so that plants flowering before mid-August have in general obtuse middle cauline leaves, (0-)2-6 internodes, few branches, and internodes longer than the leaves; plants flowering after mid-August have acute middle cauline leaves, 6—12(—15) internodes, many branches and leaves longer than the internodes. Much of the confused nomenclature results from the intersection of these morphological gradients with other more definite characters; most of the morphological nodes thus formed have been given specific rank. Confusion has arisen also from the variable duration of the plants; most are overwintering annuals, germinating in late summer and autumn to form rosettes of 4-10 acute, lanceolate leaves. This rosette withers during winter in most species, leaving only a small bud. In spring, the secondary rosette formed from this bud has obtuse, oblanceolate or spathulate leaves. Sometimes spring or early summer germination is followed by flowering in the same year from the primary rosette, and these phenological differences may again transgress the usual taxonomic boundaries. Hybridization is apparently common and hybrid swarms occur in zones of overlap between species.