Chao Hsiu-Chien
J Syst Evol. 1951, 1(3): 343-359.
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.
