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A Study on Numerical Taxonomy of Dioscoreaceae Plants in Zhejiang Province

Xi Jing-Qing, Mao Zong-Xiu, Yang Jian-Wei, Xi Ke-Chun   

  • Received:1900-01-01 Revised:1900-01-01 Online:1990-11-10 Published:1990-11-10
  • Contact: Xi Jing-Qing

Abstract:

 The present paper deals with the numerical taxonomical study of  Dioscreaceae
plants all from Zhejiang Province. In the only genus Dioscorea 17 species and 1 variety were
used as 18 operational units (OTU). Among 72 characters used for analysis  60 are morpho-
logical, 5 anatomical, 4 chemical and 3 geographical. The Gower's  Coefficient of similarity
was used for showing quantitative index of similarity among the OTUs. By means of methods
of systematic cluster: shortest distance, longest distance, middle distance A (β=0), middle
distance B(β=1/4), centre of gravity, class average and square sum of deviations, dendrog-
rams from every method were obtained respectively. All calculations and dendrogramsmaking
were treated on IBM computer with the program by BASIC language.
      The result shows that the classical taxonomy is reasonable on the whole, but none of  7
dendrograms is identical with the classical taxonom and only the middle distance B(β=1/4)
is the most similar to that. Based upon the relationships among these plants as shown in both
classical and numerical taxonomy, 5 OTUs are chosen for discussion as follows:
       1. Dioscorea collettii Hook. f. var. hypoglauca (Palibin) Pei et Ting and D. zingiberen-
sis C. H. Wright would be better still maintained together in Sect. Stenophora Uline as classi-
cal method treated according to their horizontal and diosgenin-containing rhizomes and mon-
ocolpate pollen grains.
      2. D. bulbifera L. and D. pentaphylla L. both have vertical, turbinate and no diosgenin-
containing rhizomes, left-twining stems and dicolpate pollen  grains, but the latter is  rema-
rkable for its compound leaves, so they would be better maintained in Sect. Opsophyton UL-
ine and Sect. Lasiophyton Uline respectively as classical taxonomy treated.
       3. D. cirrhosa Lour. has been included in Sect. Enantiophyllum Uline, but its rhizomes
containing abundant tannin, ligneous stems and narrowly ovate to lanceolate, coriaceous leaves
are quite different from those of other member in the section. Therefore it is suggested that
this species be separated from the original section and a new section be established for it.

Key words: Dioscoreaceae, Dioscorea, Zhejiang Province, numerical taxonomy, Dioscorea cirrhosa Lour