A HISTORY OF NORFOLK a well-established weed in many places, and has been found in every one of the four divisions into which Norfolk has been divided. Erigeron Canadense, certainly ' alien ' in its origin, appears (as mentioned in the account of the '5C' division) likely to become in suitable localities more numerous than the ' native ' Erigeron acre. Many ' casuals,' such as Adonis astivalis, Tamarix gallica, Spiraa tomentosa, Sambucus racemosa, Lamium maculatum, have been taken no notice of. This very year (1900) three casuals have appeared, two in the northern part of the county, Abelia unijiora, native of China and Japan ; Solanum rostratum, native of Mexico ; and one in the southern part, Carduus benedictus, native of South Europe : and so long as the practice of purchasing foreign ' seeds ' is continued, and it is certain to increase rather than diminish, fresh ' casuals ' will spring up, most of them to die out after a few years, but possibly a few to hold their own and by-and-bye to claim a place in future editions of the London Catalogue. The following species have been omitted in compiling the table, although they have been reported or published as found within the county on seemingly good authority. The reasons for doing so in the cases of Thalictrum majus, Stellaria nemorum, Statice rarijiora, Veronica spicata and Juncus balticus are given in the accounts of the ' ^C ' and ' w ' divi- sions. Brassica oleracea is omitted because it has been recorded from all four divisions, thus raising great doubt whether it is anything more than an escape of the cultivated plant. Crithmum maritimum as too difficult to trace, being only recorded 1 20 years ago. Inula crithmoides was only a single specimen 116 years ago in an unlikely situation, and is regarded as an unclaimable ' casual.' Cnicus heterophyllus as not having been found lately in the neighbourhood whence reported, and C. pratensis abundant there having so often been mistaken for it. Cynoglossum germanicum not to be found now, and a subglabrous form of C. officinale^ likely to be mistaken for it, being common in more than one locality. Symphytum tuberosum, a mistake suspected. Pulmonaria officinalis, probably only a garden escape. Festuca sylvatica and F. dumetorum for want of sufficient information ; and Equisetum variegatum for uncertainty. It is useless in a County History to speculate on the origin of the British flora, that being a subject which could only be profitably treated of by considering Great Britain as a whole ; but it is clear that ever since land and water assumed approximately their present positions in this part of Europe the coast of Norfolk must have been the western boundary of the embouchure of the river Rhine or of the probably much larger river which in time past occupied its place and which must, especially in times of flood, have stranded many species on our shores. Mr. Clement Reid in his Origin of the British Flora has given (p. 171) a list of the plants whose fossil remains he has recovered from the Cromer Forest Bed, a Pre-Glacial deposit. Of all these (77) ' aquatic and wet-meadow species and forest trees ' there are only three, Trapa natans, Naias minor and Picea excelsa, which are not now ' natives of Britain ' and of the remainder there are but two, Pinus syhestris and 42
