A HISTORY OF DEVONSHIRE 



specific for childblains.' There are other unsatisfactory records for its 

 occurrence both in north and south Devon. Mr. Moyle Rogers found 

 it as a casual on a garden wall at Teignmouth, but he does not on this 

 account regard the species as a Devon plant. Mr. Ralph Morgan of 

 Heavitree also about twenty years ago found it growing in the hedges of 

 Stoke Wood about 2| miles from Exeter, but on subsequent searches 

 failed to find it again, and he agrees that without further evidence the 

 species ought not to be included in the Devon list. 



The sea-cudweed or cotton-weed {Diotis maritima) was reported by 

 Withering {Bot. Arr. p. 707) to occur in the county, and in Croydon's 

 Torquay Guide^ p. 163 (1841), it was recorded under the name of 

 ' Gnaphalium marttimum (sea cotton- weed) ' for Babbicombe. The old 

 records are probably correct, but there is reason to fear that the plant is 

 now extinct in the county, and it is therefore not included in the summary. 



Altogether about 125 species, which are included in the London 

 Catalogue^ and of which the records for the county are considered on 

 various grounds to be unsatisfactory, have been rejected and are thus 

 excluded from the census. 



The summary shows 867 Devon species of dicotyledons and 271 

 species of monocotyledons ; these figures are nearly in the proportion of 

 16 to 5. In Jones and Kingston's Flora Devoniensis (1829) the number 

 of dicotyledons mentioned is 605 and that of monocotyledons 193 ; these 

 are approximately as 47 to 15. In Ravenshaw's List of Plants in Devon 

 (1872) the corresponding proportion is 60 to 19. In Mansel-Pleydell's 

 Flora of Dorsetshire (ed. 2, 1895) the number of dicotyledons is to that 

 of monocotyledons nearly as 19 to 6 ; this is a rather smaller proportion 

 of dicotyledons than prevails in Devon. In Archer Brigg's Flora of Ply- 

 mouth (1880) the proportion is nearly 7 to 2. The Student's Flora of the 

 British Islands (ed. 3, 1884) contains species of these groups, the numbers 

 of which are approximately in the proportion of 3 1 to 11. The London 

 Catalogue (ed. 9, 1895) contains corresponding figures which are nearly 

 as 3 to I ; this comparatively high proportion is due to the enumeration 

 of the critical species of the brambles and hawkweeds. 



A comparison of these sets of figures nicely confirm the general 

 law arrived at by Robert Brown (Appendix iii. to Flinders' Voyage to Terra 

 Australis, vol. 2, pp. 537, 538) in 18 14, ' that from the equator to 30° of 

 latitude, in the northern hemisphere at least, the species of Dicotyledonous 

 plants are to Monocotyledones as about 5 to i ; in some cases considerably 

 exceeding, and in a very few falling somewhat short of this proportion ; 

 and that in the higher latitudes a gradual diminution of Dicotyledones 

 takes place, until in about 60° N. lat. and 55° S. lat. they scarcely equal 

 half their intratropical proportion.' 



The larger dicotyledonous orders are comparatively more fully 

 represented in Devon than are the monocotyledons. The following list 

 shows in descending scale, for each order represented by at least as many 

 species as Hypericinese, the percentage borne by the number of Devon 

 species to that in the London Catalogue : — 



60 



