| Abstract: | The morphological characters in the genus Orobanche were evaluated from thetaxonomic point of view. The author finds that the plants of this genus are relatively similarto each other in respect to characters of vegetative organs, fruits and seeds. But the differencesin the floral structures can be served as a basis for delimitating infrageneric taxa. The seedcoat of 18 species and pollen grains of 6 species were also examined under scanning electronmicroscope (SEM). They seem to have little significance for distinguishing species. The result supports G. Beck’s (1930) division of the genus Orobanche into 4 sections, ofwhich 2 occur in China, based on the characters of the inflorescence, bracteoles and calyx.The author considers that some characters, such as anther hairy or not, upper lip of corollaentire or not, lower lip longer or shorter than the upper one, the state of corolla-tube inflec tion and the hair type of filaments and plants, are important in distinguishing Chinese species. A key to the species of Orobanche in China is given. This genus consists of about 100 species, and is mostly confined to Eurasia, with over 60 species found in Caucasus and Middle Asia of USSR, where may be the mordern distribu tional centre. Orobanche L. in China is represented by 23 species, 3 varieties and l forma. As shown in Table 1, most species (12 species) are found in Xinjiang, which clearly shows a close floristic relationship between this region and Middle Asia of USSR. 6 species are endemic to China, of which 4 are confined to the Hengduan Mountains (Yangtze-Mekong-Salwin divide). The relationships between this genus and related ones of Orobanchaceae are also discussed. The author holds the following opinions: the genus Phelypaea Desf. should be considered as a member of Orobanche L. Sect. Gymnocaulis G. Beck, the monotypic genus, Necranthus A. Gilli endemic to Turkey, is allied with Orobanche L. Sect. Orobanche, the monotypic genus, Platypholis Maxim, endemic to Bonin Is. of Japan, is far from Orobanche L. in relation and should be regarded as a separate genus. The 11 OTU’s, including all the sections of Orobanche L. and 7 genera of Orobanchaceae, and 15 morphological characters were used in the numerical taxonomic treatment to test the above-mentioned suggestions. After standardization of characters, the correlation matrices were computerized. The correlation matrices were made to test the various clustering methods. At last the UPGMA clustering method was chosen and its result is shown in a phenogram. The result of numerical analysis is basically in accordance with the suggestions. |
