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Visit to Kew Aug 20/47

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Hooker admits that there are more peculiar species on Mountain summit of islands than on the low-lands. He admits it for St Helena, & Galapagos & Teneriffe: but then at Galapagos genera more allied (with the exception of compositæ which are most anomalous in all islands) great tendency to change to those of Cordillera, & on summit of Teneriffe we have Pinus, Spartium & Ilex which are N. or Europæan genera

N. B. The connection by land (if by land) must have been very long continued to have introduced by land colder & warmer plants. Bunbury alpine Madeira plants (cold Period) Again I am forced to cold mundane theory. Hookers says so many plants alter appearance in going up mountains that if you could kill intermediate form, you wd have two species; says he knows cases in Eucalyptus. Now introduction of new forms adapted to such climate wd undoubtedly do that.

If islands are very old, at their present level, then there was originally warmer country vegetation; then came on colder period & the warmer plants wd all be killed & that then

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Mountain plants descend & at present day be redriven up - But in islands of moderate age - other of moderate elevation, lowlands plant wd be killed or rendered less adapted to station & cold mundane plants wd be dispersed over lowlands of world - when actual warmer period came on, there wd be driven up. [illeg] would thus have undergone several small changes & wd be specifically altered & new warmer plants wd be introduced but then wd be less altered, Hence, the greater generic affinity & less specific affinity of insular & continental alpine regions. There remains the production of many species on same island; oscillations of climate wd tend to make this. But it is a difficulty.

[in margin:] With respect to Equatorial plants having been all killed, we shd err much, if we judged of absolute capacity of plants to bear changes, by their relative capacity compared to better fitted plants.