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Teratological Variations of Stamen in Lawiella chinensis Chao (Podostemonaceae) in Relation to the Taxonomic Position of the Genus

Chao Hsiu-Chien   

  • Received:1900-01-01 Revised:1900-01-01 Online:1951-11-18 Published:1951-11-18
  • Contact: Chao Hsiu-Chien

Abstract:

1. A number of teratological variations of stamens were found in Lawiella chinensis
    Chao. According to Masters’ Vegetable Teratology, these variations may be classified
    into the following groups: 1. Polyphylly of androecium; 2. Atrophy of stamen, which
    is divided into: a. Abortion of stamen, b. Degeneration of stamen; 3.  Fission of
    anther-sacs; 4. Pistilody of stamen, which may again be divided into: a. Connective
    conlerted into stigma, b. Antber-sac converted into stigma, c. Anther-sac converted
    into pistilodes and pistil, d. Filament converted into pistilodes, e. Stamen converted
    into pistilodes, f. Stamen converted into pistil, g. Stamen converted into pistil and
    pistilodes; and 5. Pollen replaced by ovules.
2. These  variations are  not  due  to  the  effect  of  environmental  changes  on
    account of the facts that various malformation of stamens can be found at the
    same time from a single plant and the similar changes can also be seen from the
    different individuals during the flowering season of this plant.
3. Tapels are found in many genera of the family Podostemonaceae.  Many authors
    thought that they were the perianths while others regarded them as the staminodes.
    But the writer believes that in Lawiella chinensis Chao, a stamen may be reduced
    to a tapel and the tapel may also become a complete stamen.  He thus suggests that
   tapels should be regarded as degenerated stamens.
4. From the argumentation of stamens, tapels and pistilodes, the writer thinks that
   there are approximately 6 stamens in each flower of the genus Lawiella Koidz.  The
   number of stamens was greatly reduced through a long period of evolutionary changes,
   until only one or two remain in the present flower.  The greater the number of
   stamens, the more primitive it is and vice versa.
5. According to the original description of the genus Lawiella Koidz., published in
   1931-1935, it was considered as mono-staminous.  The di-staminous condition is
   however, not uncommon in Lowiella chinensis Chao and in Lowiella Doiana Koidz.
   The writer, therefore, proposes that the number of stamens of this genus should
   be two to one.
6. The form of brachyclades and rhizomes of Lawiella Koidz. is very similar to that 0f
   the di-staminous genus Mniopsis Mürt. et Zucc. and that of the mono-staminous genus
   Cladopus Müller. Moreover, the humber of stamens of Lawiella Koidz. is 2-1, so
   that the taxonomic position of this genus should be placed between the two genera.
7. Up to the present, 5 species of the genus Lawiella Koidz. have been reported, of which
   3 are known to occur in Kyusiu, Japan and the rest in Fukien, China. So far nothing
   is known of the taxonomic position of this genus. An attempt is made in the
   present paper to separate various species of Lawiella Koidz. on the basis of the
   number of stamens:
   1. L. chinensis Chao: stamen 2-1, which are well developed or sometimes slightly
       reduced.
   2. L. Doiana Koidz.: stamen 2-1, if two in number, the anthers of one or both
       stamens are not well developed.
   3. L. kiusiana Koidz.:  stamen 1, all or one of the tapels usually changed into
       staminoid.
    4.  L. austrosatsumensis Koidz.: stamen 1, and is very similar to L. kiusiana Koidz.
       in its stigma and other vegetative characters.
    5. L. fukienensis Chao: stamen 1 and without any change.

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