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The Geographical Distribution and the System of Aristolochiaceae

Ma Jin-Shuang   

  • Received:1900-01-01 Revised:1900-01-01 Online:1990-09-10 Published:1990-09-10
  • Contact: Ma Jin-Shuang

Abstract:

The geographical distribution, the center of distribution and differentiation of
Aristolochiaceae, its subdivision and evolutionary trends are discussed in this paper.
     I.  The systematic positions, the distribution patterns and the relationships among six ge-
nera in the family Aristolochiaceae, i.e. Saruma, Asarum, Thottea, Holostylis, Aristolochia and
Euglypha, are discussed, and according to the floristic analysis two patterns and five subpat-
terns of distribution of the six genera in the family are recognized.  They are:
     1)  Temperate pattern: a. Eastern Asia (China): Saruma; b. North Temperate (disjunct in
Europe, E. Asia and N. America): Asarum.
     2)  Tropical pattern: c. Tropical Asia: Thottea; d. Tropical America: Holostylis, Eu-
glypha; e. Pantropic: Aristolochia.
     2.  The floristic analysis of species in the family shows that the region, the richest both
in genera, species and endemic species, as Takhtajan's (1969) work pointed out, is East Asia
(see Table 1); and the species in the Old World, especially in East Asia, are primitive el-
ements.  Four genera and 91 species of this family occur in China, and especially more primi-
tive elements are found from the Hengduan Mountains to South China, as C. Y. Wu's (1979)
work mentioned (see Table 2).
      3.  The primary center of the distribution and differentiation of this family is East Asia
(especially in the region from the Hengduan Mountains to C. and S. China), since four
genera and 214 species are found in Asia, and three genera and 73 species of the family,
including the most primitive genus Saruma and the more primitive genus Asarum occur in the
region from the Hengduan Mountains to C. and S. China.  The secondary center of distribu-
tion and differentiation is Tropical America, because species found there are only relatively
advanced ones.  For this reason this family should be considered as a mainly tropical family
rather than a typically tropical one, though 80 percent of the total species of the family are
now distributed in the tropics.
      4.  The evolutionary trends in the family are: the perianth from actinomorphic to zygo-
morphic, from free to united, from cup-like to tubular; stamens from indefinite to definite,
from free to united with pistil in the gynostemium; and the fruit from follicular capsule to
capsule.
     Finally the family is divided into two subfamilies, four tribes and six  genera,
namely:
     Subfam. 1. Asaroideae                 Gen. 3. Thottea Rottb.
        Trib. 1. Sarumeae Schmidt     Subfam. 2. Aristolochioideae
           Gen. 1. Saruma Oliv.          Trib. 4. Aristolochieae
        Trib. 2. Asareae                    Gen. 4. Holostylis Duch.
           Gen. 2. Asarum Linn.            Gen. 5. Aristolochia Linn.
        Trib. 3. Bragantieae Klotz.         Gen. 6. Euglypha Chod. & Hassl.

Key words: Aristolochiaceae, Geographical distribution, Center of distribution and Differentiation, Evolutionary trends, System