XVI 



Obituary Notice of Fellow deceased. 



were amplified by himself into a more detailed survey in his 1869 address to 

 the Linnean Society. Hooker insisted on the distinctness of the two great 

 Northern and Southern floras. While admitting that they may have had a 

 common origin in the past, it could not have been " within comparatively 

 modern geological epochs." He puts them in striking contrast. The Northern 

 occupies a vast land surface from which it has sent down invading streams in 

 every direction southwards ; its " tendencies " are " usurping." The Southern, 

 on the other hand, is broken up into three subordinate floras in dissevered 

 areas ; its northward migration, if it be one, and not as Darwin thought a 

 retreat, is feeble. It appears to be doomed to extinction, and everywhere we 

 see its peculiar forms " dying out in small areas." They are subject in fact to 

 the nemesis of excessive specialisation, which implies a greater antiquity. 

 They will succumb before " that power of appropriation in the strife for 

 place " in which Hooker saw a " force ... of the real nature of which 

 power no conception has been formed by naturalists, and which has not 

 even a name in the language of biology " (p. civ). Hooker singled out as 

 notable the " continuous current of vegetation " which extends from 

 Scandinavia to Tasmania, " the greatest continuity of land " " of the terrestrial 

 sphere," and the next in importance the Himalayan along the same arc, 

 dying out in Malaya. The former he worked out (1862) in great detail 

 in his classical memoir, " Outlines of the Distribution of Arctic Plants " 

 ('Trans. Linn. Soc.,' vol. 23, pp. 251-348). He showed that "the Scandi- 

 navian vegetation ... in every longitude . . . migrated across the tropics 

 of Asia and America" (p. 253). Few now probably will accept Darwin's 

 explanation that this took place during a refrigeration of the tropics; the 

 facts Established by Hooker remain, however, unshaken. Darwin in this and 

 other cases sometimes indulged in hazardous deductive speculation ; Hooker 

 relied on laborious inductive investigation. The result was to place plant 

 distribution on an entirely new basis. The flora of a country could no 

 longer be regarded as the outcome of local physical conditions, but was 

 derivative from a former order stretching back into a remote past. The gulf 

 between the two conceptions is immeasurable. 



In 1866 (August 27) Hooker delivered before the British Association at 

 Nottingham his celebrated lecture " On Insular Floras." This was published 

 at the time in the ' Gardeners' Chronicle,' but not separately printed (without 

 alteration) till 1896. He indulged in an amusing allegory to represent the 

 celebrated discussions at Oxford (L.L., vol. 3, p. 48) in which he had been 

 called on to ' take part, and had triumphed over the Bishop of Oxford's 

 ignorance " of the elements of botanical science " (L.L., vol. 2, pp. 322-3J. 

 He thought that " neither geological considerations, nor botanical affinity, 

 nor natural selection, nor all these combined, have yet helped us to a com- ^ 

 plete solution of this problem, which is at present the bete noire of 

 botanists " (p. xv). He concluded that " the hypothesis of trans-oceanic 

 migration, though it leaves a multitude of facts unexplained, offers a rational 

 explanation of many of the most puzzling phenomena that oceanic islands 



