752 
VEGETATION SURVEY OF NORFOLK. 
Gampylopus pyriformis, Dicranum scoparium, Brachythecium 
albicans, and Hylocominm squarrosum as the common mosses. 
On the cultivated portions reverting to heath, Agrostis tenuis 
and Festuca ovina were dominant grasses, with Anthoxanthum 
odoratum, Holcus mollis, Arrhenatherum elatins, Cyno- 
surus cristatns, Dactylis glomerata, and Festuca rigida 
also abundant. 
Crostwick Common is heath pasture on Norwich Crag. The 
few scattered trees are ash, oak, and elm. There is a scrub of 
thorn bramble and briar with bracken and broom, but no gorse. 
On river gravel near the stream there is a trace of ling. The 
following are the chief constituents of the carpet : — 
Tri folium prat ease 
Potentilla erecta 
Galium veruin 
Achillea millefolium 
Senecio Jacobcea 
Cnicus lanceolatus 
Gentaurea nigra 
Campanula rotundifolia 
Thymus serpyllum 
Prunella vulgaris 
Plantago lanceolata 
Plantago coronopus 
Plileum pratense 
Agrostis tenuis 
Holcus lanatus 
Sieglingia decumbens 
Cynosurus cristatns 
Festuca ovina 
On much of the grass heath either Ulex or Pteris is 
dominant with Agrostis tenuis sub-dominant, varying in 
height from three to twenty-eight inches. North-west of 
Telegraph Hill, Honingham, Ulex attains a height of ten 
feet. The bracken rhizomes appear to rest on the top of 
the gravel on Costessey Common at a depth of four to six 
inches, with roots penetrating the gravel for two feet or more. 
A pit section at the foot of Ringland Hills showed twenty-six 
inches of soil resting on chalk. The main bracken rhizomes 
were four inches below the surface, some extending to sixteen 
inches, and beneath these the roots of furze and honeysuckle 
penetrated. On Ringland Church Common bracken rhizomes 
were seen at a depth of two feet, where they rested on gravel 
which showed a few tongues of chalky boulder clay. The 
vegetation of this common is typical of an ancient grass heath 
