VEGETATION SURVEY OF NORFOLK. 
747 
unusual crops noted were reedgrass (Digraph is), a strip 
apparently planted for game in Witchingham, and maize, grown 
as green fodder at Hethel, and sown regularly as covert for 
partridges at Horsford. The common occurrence in the fields 
of pits, from which clay and marl were dug for a top dressing, 
and the great volume of material that has been removed from 
the larger of them, indicate the lengthy period during which the 
problems of agriculture have been studied in East Anglia. On 
the light soils where clay occurred in boulder form, and has 
been entirely removed, the pits are dry, often containing a 
growth of scrub ; on the boulder clay the pits hold water, 
unless, as often happens, the excavation extends to an under- 
lying porous bed. Floating and rooted aquatics such as duck- 
weed, bur-reed, water-dock, pond-weed, reed, etc., commonly 
occur. Very few weeds are entirely restricted to either heavy 
or light lands under cultivation. The tendency for poppy, 
spurry, sandwort, knawel, and others to dominate sandy soils, 
and Equisetum and Atriplex to become pests on clay lands, 
shows their natural proclivities ; but they possess a considerable 
range of adaptibility, and we formed the conclusion that within 
the area the amelioration of extreme conditions by tillage and 
mulching favours a general distribution of all the common farm 
weeds. On the less disturbed parts of farm lands, such as 
hedgerows, ditch-sides, and permanent pasture, coltsfoot 
( Tussilago ), butterbur ( Petasites ), dog’s mercury, and cowslip 
were specially typical of heavy soils, as also were certain 
mosses. Porotrichum alopecurum lines the hedges in sheets 
at Hethel and elsewhere, but is absent from the light lands. 
Having regard to the supposed usefulness of lime for controlling 
buttercups, it is worth noting that Ranunculus repens is usually 
a common weed in chalk and marl pits, in a much dwarfed 
state forming a border at the edge of the talus. Roadside and 
hedgerow timber is chiefly oak ( Quercus Robur, var. peduncu- 
lata), elm ( Ulmus campestris ), and ash. Quickset fences 
consist mainly of blackthorn (Primus spiuosa) and whitethorn 
(Crataegus monogyna) ; holly, maple, elm, and tea-plant 
(Lycium) being much used for repairing weak places. 
