The Presidential Address. 
21 
occupied as weeds tlie manure and rubbish-heaps and waste 
ground of civilisation. 26 Such were probably the Mousetail 
( Myosurus ), the Mustards ( Sinapis ), the Penny-cress ( Thlaspi 
arvense), the Groundsels ( Senecio ), the Sow-thistles ( Sonchus), 
the Black Nightshade (Solarium nigrum), and probably the 
Celandine (Chelidonium), the London Bocket (Sisymbrium irio ), 
and the Stinging Nettles (TJrtica urens and U. dioica). The 
only argument against the indigenous character of these 
plants is that after the appearance of man they have chosen 
to grow on the most richly manured land available to them, 
thus frequenting his waste-heaps and cottage hedgerows. 
With a greater rainfall and no artificial drainage far more 
of the stiffer soils of Essex than at present must have been 
marsh or peat-bog. 27 The fall of a tree will dam a stream 
and originate a pool of stagnant water, which may become 
entirely blocked by Sphagnum, Osmunda, or Golden Saxifrage 
(Chrysosplenium) . On the peat thus forming Marsh-mari¬ 
golds (Caltha), Sundews (Drosera), Pennywort (Hydrocotyle), 
Whortleberries (Vaccinium), the Bog Pimpernel (Anagallis 
tenella), the Spotted Orchis ( Orchis metadata), the Ivy-leaved 
Bellflower ( Wahlenbergia hederacea), the Bed-rattles (Pedicu- 
26 See DeCandolle, op. cit., pp. 650,652, sub Chelidonium and Sisymbrium 
irio. 
27 The following account of the Cambridgeshire Fen is suggestive with 
reference to some parts of Essex :—“ As the character of the Fen district 
is very little known, it is well to remark that the peat is not formed of 
Sphagnum, like that of the bogs, but consists chiefly of the remains of 
various aquatic herbaceous plants. At the bottom there is a layer 
formed mostly of the remains of the woody plants and trees which con¬ 
stituted the forest which formerly covered the country. The remains of 
oak, yew, hazel, and willow are found abundantly in some parts of the 
Fens, and pine wood is plentiful in others. The wood of the larger trees 
is often well preserved and turned quite black, but a few inches of the 
surface have become soft and spongy. The latter is the condition of 
most of the smaller branches and the lesser ligneous plants. The Eev. 
Leonard Jenyns informs us that it is the opinion of the turf-cutters at 
Isleham that, before the present more perfect drainage of the Fen, the 
turf grew at the rate of about twenty inches in sixteen years. Now the 
want of sufficient water has put an end to this restoration of the turf in 
the places where it has been cut for fuel.”—Professor Babington, ‘ Flora 
of Cambridgeshire,’ p. xviii. 
