94 
S. IKENO : 
its flowering begins in June and continues till the end of October. Flowers 
are beautiful and pretty large ; they begin generally to open at about 8 
o’clock morning under sunshine, and wither at about the noon of the same 
day, though in dull weather or in late summer it may continue to open much 
longer. Each flower is provided with two sepals and five to six petals ; there 
are very numerous slender filaments derived from five stamens by copious 
ramification ; there is one ovary with one style and five to six radiating 
stigmas, which ripens into a pyxis containing a large number of tiny kidney¬ 
shaped seeds. In respect to the colour of the petals there are, so far as I 
know, five different kinds : they are, namely, white, yellow, orange, flesh- 
coloured, red, and magenta (s. PI II), naturally with some fluctuations in 
their tone. Petals striped in various ways are also found. It may here be 
remarked that the flower-colour of Portulaca is always due to the cell-sap,' 
and never to the chromoplasts. 
Materials and Methods. 
The breeding experiments of several colour-varieties of this plant w T ere 
begun in 1915 to study the genetical behaviour of flower-colours. First of 
all, I have done the self-fertilisation of varieties cultivated in our Botanical 
Garden in Komaba as well as those obtained from other sources, including 
white, yellow, orange, red and magenta. Next year seeds got by such setting 
were sown. Some of the varieties thus examined were found to segregate, 
proving themselves to be hybrids ; all such ones were rejected, and only 
those which were found to breed true to their respective types were further 
cultivated, seeds being taken of course every generation on selfed flowers. 1 
From 1915 I have begun to cross these varieties in various ways, 
and are now concerned in studying the behaviour of their offspring. Many 
of these crosses were repeated, and also their offspring were also studied. 
A variety which bears flesh-coloured flowers was got first in 1917 through 
the kindness of Dr. I. Nagai in the Agricultural Experiment Station in 
Oomagari near Akita ; its hybridisation with some other colour-varieties was 
made in 1918, so that we had in 1920 their ifi-ofispring. 
1 On account of poor germination of seeds I have lost the red parent in 1917 and the 
white-I one in 1918, but I have recovered each of them afterwards by extracting them from their 
respective hybrids made some years ago, anl continue to cultivate them till now. 
