712 TRANSACTIONS OF SECTION K. 
suggesting the development of a variety with double flowers for the first time 
from these plants. 
Stem.—-Strong evidence has been obtained of the existence during the colour- 
changes of a coupling between the colour of the stem and that of the subsequent 
flowers. In no case has a plant which has been grown from seed borne flowers 
of the mauve variety if any trace of red pigment has previously appeared in the 
stem, cotyledons, or foliage-leaves. Fasciation which did not occur in the 
earlier years is not infrequent now. The normal racemose inflorescence of the 
elongated main axis and of the branches has been much modified, the stalked 
leaves being suppressed altogether, or appearing in a very much reduced form 
upon the axis of the flower itself. The latter is now common in the case of the 
branches, and when the leaves are entirely suppressed it resembles a cymose 
inflorescence, in which each relatively main axis bears one lateral branch. On 
the main axis of the plant two stalked leaves and two axillary flowers will arise 
at the same node. 
Plants of dwarf habit have appeared, though there were none originally. 
This character has been much studied. It has never been transmitted by the 
seed unless careful attention has been paid to the screening and a maximum 
amount of low sun afforded. Screened seedlings have now continued the habit 
for three generations, while unscreened from the same parent have reverted to 
climbers. 
No difficulty has been experienced in keeping these annuals alive a second 
and third year, however much the colouring-pigments may have been changed. 
One plant is now in its fourth year. This recalls the fact that perennial varieties 
of the species are established and recognised. 
Flowers.—A method has been devised by which the changes that the 
colouring-pigments undergo are recorded and reproduced by colour photography 
(lantern slides). This has enabled the effect of screening the same variety at 
different hours to be observed and the results to be classified. Markings on 
petals have been removed altogether, or, in other cases, intensified and enlarged 
so as to suffuse the whole face. Honey-guides have been removed. 
Nothing has been done to prevent the mauve variety from fertilising or 
being fertilised by the other varieties, and it is probable that all now contain, 
though in a masked form, the colouring-pigments which go to make up the mauve 
colour. The latter is now to be seen in a large variety of shades. To produce 
modifications in any colouring-pigment it is not now necessary to screen the 
whole plant from the time the seedling appears. Each branch may be screened 
differently and slight but distinct colour-variations are obtained in the flowers. 
In one case where a plant was treated in this way, in an isolated bed, two new 
varieties were obtained in the following year from its self-sown seed. One of 
these bore simultaneously flowers varying from primrose to suffused rosy-fawn, 
many being cream splashed with rose. It was identified as a climbing variety 
of Aurora which is mentioned in Nicholson’s Supplement, 1900, to ‘ Illustrated 
Dictionary of Gardening’ as a recent introduction. A large number of plants is 
now annually obtained which are variable as to colour, and this variation is 
being transmitted through the seed. A salmon-pink with mauve patches has 
appeared, recalling a variety of Antirrhinum majus which sports in the same 
way. Four new varieties have appeared in 1913. 
Structural Changes.—Besides those changes which have already been referred 
to, flowers with a short blunt spur (a recognised variety), or with none at all, 
or with two and three spurs, have become common, and are transmitted through 
the seed. Such flowers modify the petals. as many as six sessile petals or four 
sessile and two unguiculate arising instead of the normal two sessile and three 
unguiculate. 
Sun’s Altitude.—The experiments which have now extended over eight years 
definitely point to a connection between the variations of colour and structure 
and the sun’s altitude, both seasonal and diurnal. Since January 1911 they have 
been followed with the microscope and the modifications noted, not only of the 
colouring-pigments contained in the cells, but of the forms of the epidermal 
papillary cells themselves. 
There seems little room for doubt that by this method of screening, which 
departs but slightly from the conditions to be found in nature, metabolism has 
