874 
Wilson.—Plant Distribution in the 
the deeper ones the great abundance of Carduus palustris probably has 
a detrimental effect on its distribution.. 
In addition to the above-mentioned plants, the following biennials and 
perennials are occasionally found :— 
Sagina procumbens , L. 
Hypericum pule hr um, L. 
Epilobiimi roseum , Schreb. 
Daucus Cctrota , L. 
Dipsacus pilosus , L. 
Gnctphalium sylvatiemn, L. 
Solanmn Dulcamara , L. 
Veronica serpyllifolia , L. 
Prunella vulgaris , L. 
Orchis mascida , L. 
Orchis maculata , L. 
Gymnadonia conopsea , R. Br. 
Lister a ovata, R. Br. 
Juncoides pilosum , O. Kuntze. 
Brachypodium sylvatiemn , Beauv. 
A considerable number of weeds of cultivated ground, hedgerow plants, 
and plants of waste places (ruderal plants) are occasionally found on the 
Clay ; of these the following annuals flower in the first season :— 
Alliaria officinalis , Andrz. 
Stellaria media , Vill. 
Arenaria serpyllifolia , L. 
Torilis Anthriscus , Gaert. 
Matricaria inodor a, L. 1 
Senecio vulgaris , L. 
Solanum nigrum , L. 
Plant ago lanceolata , L. 
The following perennials flower for the first time in the second season 
and generally disappear in the later years :— 
Lepidium heterophyllum , Benth. Chaerophyllum sy Ives ire, L. 
Viola tricolor , L. Heracleum Sphondylium, L. 
Lyclmis alba , Mill. Helminthia echioides , Gaert. 
Fart# sepium , L. Hypochaeris radicata , L. 
Few Mosses are found in the shade produced by the older coppice growth, 
but after felling there is a considerable increase in number. Some of those 
which appear behave similarly to the biennial flowering plants with regard 
to fruiting. Catharinea undulata (L.), Web. Mohr, exists for the most part 
in the vegetative state only during the first season, but fruits abundantly 
during the second year. 
Polytrichum juniper inum, Willd., Polytrichum attenuatum , Menz., and 
Mnium hornum , L., also show this, but in a less degree. The distribution 
of these species is associated with differences in the depth of soil. Polytri¬ 
chumjuniperinum forms a narrow band on the shallow soil in the neighbour¬ 
hood of the Chalk, but is not found on the deeper soil. On slightly deeper 
soil it is replaced by a similar band of Polytrichum attenuatum . Catharinea 
undulata is abundant, but occurs only where the soil is more than about 
three feet in depth. M}iium hornum is usually confined to soil from three 
to four feet in depth, but is not found abundantly. Finally, Mnium undida- 
1 This plant is occasionally perennial. 
