32 " president's address. 



beside tbe seedling on the left. My leveision-sboots show fifteen later stages 

 that are skipped in this seedling, to be referred to later on. 



Of sixteen bush-seedling's of .1. falcata, the tirst comijlete euphyllude was the 

 fifth leaf in nine, tlie sixth in sis, and the seventh of one; the leaf immediately 

 preceding the first comijlete eviphyllode in each of two seedlings had two pairs 

 of pinnw. Of sixteen bush-seedlings of A. myrtifolia, the tirst complete euphyl- 

 lode was the fifth of two, the sixth of seven, the seventh of six, and the eighth 

 of one; seedlings of this species also sometimes have one, and occasionally two 

 leaves with two pairs of pinnse. Seedlings of A. lini folia, of which tbe first 

 complete eupbyllode may be the sixth-ninth, may also have one leaf, or two 

 leaves, or, as in one of my specimens, three leaves, with two pairs of pinna?. 

 The leaves of seedlings of A. suaveolens often sliow most interesting lingering 

 stages of dwindling pairs of pinnse, the last of which may be represented by 

 only a single pair of leaflets, with the terminal seta at the apex of the rhaehis; 

 and this is quite as conspicuous at the apices of tbe succeeding euphyllodes. 

 Further details will l)e found in Cambage's papers.* 



Thk Terminal Seta or Recurved Point of the Bipixnate Le.-isks and 

 El'phyllodes op Australian Acacias. 



No. 3 of the definitions given in Bentham's paper on the Jlimosea\ referred 

 to later on, is very important, namely — "A small point terminates the petioles 

 whether common or partial, in all or nearly all Mimoseae. It is usuaUy setifoi'm, 

 though sometimes short and thick, and occasionally almost foliaceous, sometimes 

 apparently continuous with the jjetioles [i.e., the common or partial petioles as 

 defined on p 324; but not petioles in the sense in which some later authors use 

 the term, foLuwing Kunth], at other times falling readily oflE. This point has 

 by some been termed a gland; but, it would appear, erroneously. It may pos- 

 sibly be the rudiment of a terminal i)inna or leallet ; but as there is no evidence 

 beyond its position [i.e., terminating the common or partial petioles] to show 

 that it is so, I have been unwilling to give it any other name than seta termiiialis.'' 



Now this was written some seventeen years before the publication of Dar- 

 win's "Origin of Species." Chapter xiii., of the "Origin" deals, in part, with the 

 subject of Rudimentary Organs. Darwin's treatment of the subject gave an 

 altogether new view of the imjjoi'tanee and significance of rudimentary organs 

 and vestigial structures. To-day, remnants and \estigial structures mean very 

 much more to the morphologist than they did seventy-eight yeare ago. Then, 

 Bentham knew of "no evidence, beyond its position,"' to say more than that the 

 seta terminalis was possibly "the rudiment of a terminal pinna or leaflet." To- 

 day, I imagine, no one qualified to speak, will take exception to the statement 

 that it really is, what Bentham, seventy-eight years ago, said it possibly might be. 

 The setn terminalis of the pari-pinnate leaf of (a.-ysia Candotleana. for example, 

 a common garden plant, or of the pari-pinnate first leaf of Acacia-seedlings, 

 undoubtedly represents the remnant of an aborted terminal leaflet, corresponding 

 to the terminal leaflet present in Rohinia pseudacaeia, for example: just as. in 

 the bipinnate foliage of seedlings or of the adult i)lants of tiie Bii)innatae, or in 

 the bipinnate foliage of seedlings, on the young euphyllndes, and frequently on 

 the adult eui)hyllodes of the Euphyllodiueae. unless accidently missing, it repre- 



* Cambage, "Acacia Seedlings." Parts i.-v. Jouvn. Proc. K. Soo. N.S.Wales, Vols, 

 xlix -liii., 191,")-19. 



