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Gentianopsis—A New Genus of Chinese Gentianaceae
Ma Yu-Chuan
Acta Phytotaxonomica Sinica. 1951, 1 (1 ):
5-19.
Gentiana was originally proposed by Tournefort in 1700. Linnaeus adopted this generic name in his “Genera Plantarum” published in 1737. He divided the genus into seven groups on the basis of different shapes of corolla and forms of floral appendages. In his “Species Plantarum” he reorganized them into three artificial ones. Forty years later, Moench established a new genus, Gentianella under which he described G. tetrandra as the type of his new genus. In the view of identity of Gentianella tetrandra with Gentiana campestris L., it is evident that Gentianella represents only some plants formerly included in Gentiana at Linnaeus time. In 1796, Froelich’s monograph on Gentiana appeared. In his work four sections were represented and one of them was Crossopetalum. In 1845, Grisebach also published a monograph of Gentianaceae and recorded fifteen sections of which Amarella and Imaicola are two of his seven proposed ones. In 1888, Huxley studied the floral structure of Gentianaceae in relation with pollination mechanism and, accordingly, divided the family into two main groups, one with epipetalous glands, the other with glands at the base of the ovary. In each group, four types of flowers were found. He concluded that Gentiana was a complex genus on account of presence of four different types of flowers in this group, and suggested that many species of the genus should be separated out to form some smaller generic categories. Six years after, Kusnezow in his monograph divided Gentiana into two subgenera Eugentiana and Gentianella. In his system, subgenus Eugentiana consists of ten sections and the Gentianella, seven. He contributed much to the systematic treatment of Eugnetiana but little to that of Gentianella. He maintained the genus Gentiana in a broad sense. With increased knowledge of this group in the last thirty years, a number of botanists were able to make a clearer delimitation of true Gentiana and its allies and treated them in more natural way. Moench’s genus Gentianella was rerised. In 1936, H. Smith separated Megacodon from Gentianella as a genus. In the present paper, the writer suggests a generic name Gentianopsis for the section Crossopetalum in the same Genus. This new genus is characterized by (1) its large and somewhat flattened ellipsoidal flower bud, (2) two dissimilar pairs of calyx lobes which are distichously imbricate in aestivation, (3) four triangular, ciflated intracalyx membranes at the base of and alternate with the calyx lobes, (4) distinct gynophore and (5) enlarged stigma. While in typical Gentianella represented by section Amarella, the flower buds are small and terete, a laciniate corona is usually present, and the calyx-lobes are leafy, lanceolate, imbricate, and not provided with intracalyx membrane. Besides the morphological characters mentioned above, the anatomical structure of the floral parts is also a significant generic criterion. In Gentianopsis, eight vascular bundles are present in calyx, representing four dorsals and four fused ventrals. In each corolla-lobe there are five bundles. In the body of ovary six bundles are present. The ovule bearing surface is extensive covering nearly to entire surface of the ovary wall with the exception of a narrow longitudinal zone along the dorsal bundle. In Gentianella, calyx bundles are three in each lobe, without fusion of the ventrals. In each corolla- lobe, the bundles are three instead of five as in Gentianopsis but the lateral ones branch once dichotomously after entering the base of corolla. In the body of ovary only four main bundles are present due to the fusion of smaller ventral ones. The placentation is confined to the region of the ventral bundles. Phylogenetically Gentianopsis and Gentianella may be regarded as closely reIated and may represent branches of a common line with Gentianopsis standing at a lower level, Gentianella being more advanced. In Gentianella the number of bundles in the corolla segments and ovary wall are reduced by partial or complete fusion and the distribution of ovules is confined only to the region of the ventral bundles. However, in the calyx of Gentianopsis there is fusion of ventral bundles, whereas the correspound- ing bundles in the Gentianella remain separate. The Gentianopsis-Gentianella line on the one hand and the Gentiana line on the other may come again from a common acestral stock. Gentiana possesses only three bundles in each corolla-lobe. A variety
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