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M. S. Bundle 11

Jan. 4th 1855.— I see in Watson's Cybele. Taking the Monocot. (& nearly same result wd. follow from Dicot, I feel sure) but I must first remark that Watson divides Grt. Britain into 18 Provinces (18th being for northern isld) & then into 82 Counties, so that each Province includes on average 4.5 of Counties.— Now I find in Monocot that those species which are estimated (& great care has been taken p. 59 & 60) to be are found in range over 17 or 18, range each over, on an average, in each Province by calculating the estimates of counties, 4.20 counties. Whereas taking those plants which (excluding aliens) are found in only 2 to 6 inclusive counties Provinces, ie in or under 1/3 of area of Great Britain, each plant is found, on average, only in 2.06 counties.

This result wd have been even more striking had I included only those found in one Province, but aliens &c more errors than likely to be included.— So that

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it may be concluded, as Mr. Watson remarks (Cybele Brit. Vol I. p. 18) that "those most widely & generally distributed, even on large spaces, being usually also the most common species." Of course, as Mr W. remarks, this is only the first stage towards a census; & an erroneous one, as mo plants found in all 82 counties appear equally common (p. 11) whereas there is great difference in individual numbers this respect. We shd. require a return for each acre really to have accurate census.—

Hence we may rudely conclude, that wide-ranging species are commonest: thus harmonises with fact that they range far & are numerous, from same cause, viz successfully struggling with the organic & Physical conditions of Area.—

[in margin:] The number of individuals most especially depends on struggle with other individuals.