日本産リンドウ属リンドウ節植物の変異性と分類学的位置  [in Japanese] Variations in Japanese Gentiana Sect. Pneumonanthe (Gentianaceae) with special reference to their taxonomic status  [in Japanese]

Variations in gross morphology of five Japanese Gentian species (Section Pneumo-nanthe), including a newly described taxon from Mt. Kitadake, Central Honshu, Gentiana kitadakensis, were critically studied based upon herbarium specimens deposited in KYO. The multivariate analysis (Principal Component Analysis) was conducted based upon the measurements of the following 13 quantitative characters: flower length, length of the calyx tube, length and width of the largest calyx lobe, length and width of the largest leaf, length from the base to the broadest point of the largest leaf, node number which bears the largest leaf (counted from the stem base), number of stem nodes, stem length, flower number, maximum internode length, and stem diameter. Additional eight characters, i.e., flower disposition on the inflorescence, shapes of the plicae, shapes of the capsules and seeds, morphology of the stems, color of the leaves beneath, pollen morphology, and somatic chromosome numbers, were also examined and incorporated in the delimination of each taxon. As a result, each species possesses its respective unique variation patterns, characterized by the abovementioned reproductive and vegetative traits; i.e., the three species, Gentiana sikokiana, G. scabra, and G. kitadakensis, possess sharply leaning plicae with 1-2 triangular lobes and more or less undulate leaves at the margin, with pale green undersurface. In G. sikokiana, calyx lobes are ovate and stems have 5-11 nodes. Its leaves are ovate or rhombic-elliptic, short petiolate, and lacking denticulate processes at the margin. G. scabra is characterized by having linear to lanceolate calyx lobes. The stems of this species are tall, attaining ca. 130 cm, with numerous nodes ranging from 11 to 37. Its leaves are ovate-lancelolate to narrowly lanceolate, sessile, and with denticulate and scabrous margins. Among these three species, G kitadakensis possesses the largest calyx lobes, which are broadly lanceolate, conspicuously unequal in size, and furthermore erect. Its rhizomes are also characteristic, thick tuberous and with numerous contracted nodes. On the other hand, the two species, G. triflora and G. makinoi, are characterized by possessing gently leaning plicae, with 1-2 minute, inconspicuous triangular lobes. The leaves of both species are lacking undulate margins, but with glaucous undersurface. The flower size, length of the calyx tubes, and types of the corolla lobes are major characters of diagnostic value, discriminating both taxa; i.e., in G. triflora flowers and calyx tubes are larger, 34-54 mm long and 9-20 mm long, respectively. Corolla lobes are ascending or spreading, while G. makinoi has small flowers, ranging 19-33 mm long, and calyx tubes, 6-12 mm long. Its corolla lobes are erect. All these five species proved to possess the same somatic chromozome numbers of 2n=26. Pollen grains examined by SEM were similar in all four species, possessing 3-corporate 6B^b with striate or reticulate (only in G. triflora) surface ornamentation.