APPENDIX 



of Ficus and several Myristicacece, Bombacece, Lauracecs, Bixacece and 

 others, come under this head. 



The cause which has made flowers grow on the big branches instead 

 of amongst the leaves at their extremities, must be the same which has 

 made them grow on the trunk. The abnormal position of the reproduc- 

 tive organs in " Flowering Trunks " has been attributed by Wallace to 

 the circumstance that in the tropics many butterflies and other insects 

 fly in the lower part of the forests, beneath the great mass of foliage. 

 He therefore opines that flowers are thus placed low down and con- 

 spicuously in order to attract them. This may be true for some species. 

 But if it explains how flowers which have grown for the first time on the 

 stem (and not in the usual places) should continue to appear in an 

 abnormal position on account of the advantages thus obtained by the 

 plants producing them, it nevertheless does not give the physiological 

 reason of the first deviation from the general rule ; it does not explain 

 why such flowers, which habitually were produced at the vegetative 

 extremities, should suddenly have appeared in the axial parts. 



With regard to this point I would draw attention to the fact that 

 some of the AnonacecB, for instance, have flowers of a rather peculiar 

 structure, which in the phenomenon under examination might lead one 

 to suspect another and somewhat different cause than that suggested 

 by Wallace. There are abundant reasons to show that, in various 

 AnonacecB, fertilisation takes place with perfectly closed flowers, in which 

 insects, not being able to enter, have no part — in other words, belong 

 to the category of what are technically known as cleistogamous plants. 

 It is noteworthy, too, that many flowers of this family are thick and fleshy 

 and often sweetly fragrant, with a perfume which recalls that of ripe fruit. 

 It is true that odours of this kind may have been equally attractive to 

 insects, but it appears to me even more probable that they may have 

 been the means of attracting animals, who ate the flowers, mistaking them 

 for fruits. I suggest therefore that when, in the ancestors of the present 

 AnonacecB, the flowers grew on the upper portions and smaller branches 

 of the tree, the continual destruction of them by animals may have 

 been the stimulus which caused their growth on another part of the plant. 

 Such is the reason which I have already given to endeavour to explain 

 what may be termed the caulifloral condition of Durio testudinarum. 1 



In support of Wallace's opinion it might be argued that certain plants 

 which could not emulate in height the giants of the forest, and would 

 thus have been obliged to expand their flowers in the shade, hidden amidst 

 the foliage, and thus remaining unfertilised, being neglected by insects 

 whose aid is necessary to insure this operation — it can be argued, I say, 

 that as an expedient, such plants produced flowers where they were most 

 easily noticeable. In this case the non-fecundity of the flowers normally 

 placed would be equivalent to my suggestion of their destruction by 

 animals. The structure of plants is such that it is perfectly possible 

 that a stimulus felt by an individual in a given spot should produce its 

 effects in another part of the same plant. 



Of all the tissues which exist in the higher plants, the cambium is 

 that which possesses the greatest sensibility, and the faculty to multiply 

 1 Cf. Malesia, vol. iii., p. 224. 



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