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R. Brown (& Flinders) Appendix to Tuckey's Congo Voyage

p. 422 - doubts Humboldts statement of greater number of species in Tropic - On Africa & New Holland, at least, this does not exist in the Tropics but in latitude of C. Good of Hope. (so Hooker thinks): bears on their having anciently been no Tropics - thinks same conclusion is deducible from India

p 466 Vegetation nearly uniform in genera & considerable fraction of species for 1320 miles of lat. of coast

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p. 445. According to Humboldt within Tropics Compositae form 1/6 of Phænogamous plants, but in the Congo collection only 1/23 & still smaller in Roxburgs Indian & in Australia 1/16th. (a)

p. 464. Of Bignoniaceæ none in Africa though several in Madagascar, Mauritius & Bourbon & one in Johanna - The absence of Laurinæ remarkable in Africa, as several Laurus have been found in Teneriffe & Madeira, & certain other genera of same family in Madagascar, Mauritius & Bourbon. None of Myrsineæ in equinoctial Africa, though some at C. of Good Hope & Canaries

p. 472 All species of Nicotiana are American, except N. Australasiæ, but this differs so much from rest of genus, as to form a separate section of it like Hookers case (this makes distribution more striking) as if the more a species wandered, more differed

[in margin:] Hard to explain

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a. Leguminosæ according to Humboldt in tropics 1/12 of Phaenog

In Congo 1/6 perhaps 1/8 in fact owing to time of year when collection made

In India probably 1/9 which is nearly same with Australia

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p. 476 - Vegetation of St. Jago intermediate between nearest coast & Canary Isd

p. do the Congo flora agrees with that of India in its equinoctial relation of proportions of families & in many of its genera.

p. 477 to equinoctial America certainly much less affinity (ie sea greater barrier than land) Several genera, however, which have not yet been observed in India or Australia are common to this part of (a) Africa & America; also 30 actual species in common.

p. 479 The Congo species common either to India or America or to both together, are 1/12 of whole: & it is very important that the relative proportions between Monocot & Dicot & Acot in the 1/12 is nearly the same as in the whole Congo Flora. If this applied to the families, it would be good evidence

[in margin:] Is this my remark or Brown.

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(a) 23 species common to India, Africa & America

13. do common to Africa & America, not in India

17 do ― to Africa & India not in [America]

53 - these form 1/12 of whole Congo Flora which Mr B. thinks pretty perfect

Now out of these 53 there are 4 compost = 4/53 but in the whole Congo collection the proportion of Compositæ is only 1/23, = 4/92 at which rate there ought to have been less than 2 1/2 - or to put it better there are in the 53 plants 4/53 compost: the ratio ought only to have been 4/92. (nearly twice too many compositæ in the transported plants)

Of Legum in list 8 = 8/53 - the proportion actually collected in the whole collection of Leguminosæ was 1/6 or 8/48. - so that somewhat fewer Leguminosæ in the transported plants in whole collection. Again in these widely diffused Malvaceæ there are 6 species 6/53 - whereas in whole collection the proportion is only 1/34 = 6/204, so that in the 53, nearly 4 times too many Malvaceæ

[in margin:] But then I have shown how different the proportion of classes are in Humboldt & Brown.

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that they had not been wafted, but had travelled on land – Whether this applies merely to the above great divisions I am not so sure as condition might settle their [illeg], - Brown seems to think a large proportion of the seeds capable of being transported by sea-currents (p 481) because they have embryo highly developed & are well protected. In the monocot, division, thinks that quantity of albumen, (because it is here always normal) not so strong an argument against their enduring powers; (I do not see this argument)

} Hence we may conclude proportions of the nat. farms one to the other, widely different in their species common to so widely distant countries, to what they are in the vegetation of the Congo itself; hence have not travelled on land probably.

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The relation of similar Isld Aruba to America agrees with relation going to rising sun. – Even Cape of Good Hope [offing] to West side of Australia, & East side to S. America agrees, & according to this the Proteaceæ ought to have originated in Africa & gone to Australia.

It wd seem if affinities had everywhere travelled Eastward to the rising sun in Pacific owing to storms. In N & S owing to prevalent winds. None N. America plants in [illeg] islds & S Ireland – Across Atlantic affinities ought to go Eastward, if wind has anything to do. Wind govern surface [floating] & lands.