676 TRANSACTIONS OF SECTION K. 
relative amounts of red and yellow differ very considerably, so that a great range 
of colour forms have appeared. Some plants have lost their yellow plastids, but 
the anthocyanin is sometimes present in very small quantity, so that the flowers 
are pale pink in colour, the anthocyanin being mainly present in the veins. Some 
plants have flowers which are nearly pure yellow, the anthocyanin only making its 
appearance towards the end of the flowering period. In one case the flowers are 
devoid of both yellow plastids or anthocyanin during the early stages of flower- 
ing; but towards the close of the flowering period, anthocyanin makes its 
appearance at the back of the petals and they become pink in colour. 
(5) Shape of Petals.—In the f, generation a considerable variation makes 
itself manifest in the shape of the petals, both ob-cordate and ob-ovate forms 
being noted. 
Differences in the length of the claw are also apparent. 
So far no distinct carpophore has been noted in plants of the f, generation. 
The ofispring of three of the segregates of the f, generation have been raised 
by self-pollination, and several have flowered this year. So far they have shown 
little or no variation from their f, progenitors. 
My observations and cultures lead me to the conclusion that there is very little 
variation in the f, generation (the Gewm intermedium typicum of some authors), 
and that some at least of the forms named and described by Rouy in his ‘ Flore 
de France,’ and by Ascheron and Graebner in their Synopsis of the European 
Viora, are segregates produced in the f, generation of this hybrid. Other forms 
are undoubtedly due to the crossing of the hybrid with its parents. I have 
obtained these crosses which are intermediate in character between the hybrid 
and the respective parent, but, as might be expected, with a greater amount of 
variation than is shown by Geum intermedium itself. ‘Thus a very complete series 
of forms can be obtained connecting Geum urbanum with Geum rivale. 
3. The Relation of Beech Forest to Edaphic Factors. 
By Macarecor SKenz, B.Sc. 
In Great Britain natural beech forest is confined to the South of England, and 
is developed only on chalk. A type of beechwood quite distinct from this and 
belonging to the heath formation has a wider distribution, and is found on non- 
calcareous soil. In the North of England and in Scotland the beech cannot be 
regarded as native, although it has been extensively planted for about two 
hundred years, and now forms woods which appear to be self-maintaining. 
In Tansley’s ‘ Types of British Vegetation’ the true beech-forest of the South 
of England is classified as an association—layctum sylvatice calcareum—of the 
plant formation on calcareous soils, sub-formation of the chalk. The presence of 
chalk is thus regarded as the chief factor determining its occurrence. 
The chief ecological characters of the forest are (1) the intense shade obtaininz 
in the interior and (2) the thick layer of mild humus and dead leaves which 
clothes the soil. The combination of these two factors accounts for the type of 
ground vegetation. Underwood is practically absent, and frequently the soil is 
quite devoid of an herbaceous flora. Where such a flora is present it consists 
entirely of shade-loving plants: Mercurialis perennis is most abundant, and is 
accompanied by Sanicula europea, Viola Riviniana, V. sylvestris, V. hirta, 
Fragaria vesca, Circeea Lutetiana, several orchids, and the two saprophytes 
Neottia Nidus-avis and Monotropa Hypopitys. 
An association which very closely resembles this in all but floristic details 
occurs at high altitudes in the Cevennes in the South of France. Beech forest 
extends from 2,500 feet upwards, its highest limit not being reached even on 
peaks of over 5,000 feet. Here again we can recognise the leading ecological] 
features of the typical beechwood—intense shade and a thick layer of mild 
humus. Underwood is absent, and the ground vegetation, where present, is com- 
posed of shade-lovers. Anemone nemorosa is abundant and locally dominant ; 
along with it occur Ranunculus aconitifolius, _Deniaria digitata, Asperula 
odorata, Allium ursinum, Viola sylvestris, Conopodium denudatum, SLuzula 
nivea, Veronica montana, Actcca spicata, Neottia Nidus-avis, and several ferns. 
This French forest occurs typically on a schist which is conspicuously free 
