president's address. 33 



sents tbe remuaut uf a vanished terminal pinna corresponding to the terminal 

 pinna of the impari-bipinnate leaves of Caesalpinia &illiesii. (PI. ii., fig. 1) . 



Moreover the setae terminales of the reversion-foliage of A. suaveolens are 

 sometimes green and foliaceous, like incomplete leaflets or a pair of leaflets (PI. 

 i., fig-s. 4, 8, 9, 10) ; and the leaves of reversion-shoots of A. implexa (?) and A. 

 podalyriae folia sometimes have thread-like rudiments of the axes of the terminal 

 pinna present, without leaflets, but with a terminal seta at the apex (PI. viii. 5, 6). 



Admittedly, the seta terminalis is of no practical importance to the describer 

 of species. Nevertheless, in his paper on the Mimoseae, almost aU the species 

 of which have bipinnate leaves, Bentham took the trouble to discuss what he 

 conceived to be its meaning and significance. It was unfortunate, therefore, that, 

 when he came to deal with the Australian Acacias in the second volume of the 

 Flora Australiensis, especially as the euphyllodineous species far outnumber the 

 bipinnate species, he took no account of the seta terminalis, as defined in the 

 paper on Mimoseas, or of its significance, except that he merely mentions its 

 occurrence, under another name, the "recurved point," in two only of the twenty- 

 two species of Bipinnatas which he describes, as if these were the only two species 

 in which it was to be found. Thus of A. polyhotrya he says — "the rhachis ter- 

 minating in a recurved deciduous point'' (p. 414) ; and of A. leptoclada — "Pinnje 

 3-5 pairs, 3-4 lines long, on a common petiole of 1 to A in., ending in a recurved 

 point" (p. 416). 



But the recurved point, or seta terminalis, unless it is accidentally missing, is 

 usually e(|ually constant and significant, not only in other bipinnate Acacias in 

 which no mention is made of its presence; but also on the leaves of seedlings 

 of the EuphijUodineae, and at the apices of euphyllodes, especially in the young 

 stages. Bentham furnished descriptions of 271 species of ""euphyllodineous 

 Acacias. It is remarkable, therefore, that the setae terminales of some of them 

 did not attract his notice, or arouse his suspicion that the so-called phyUodes 

 of Acacias were something more than merely flattened petioles. 



Kerner is the only author known to met who rightly recognises that there is 

 3 vestigial stracture at the apex of the so-called phyllodes of Acacias, which, in 

 reality, is Bentham's seta terminalis, in which the common petiole, or the rhachis. 

 its distal component, terminates; but not the petiole, as Lubbock expressed it. — 

 Thus he says — "In many of the vetches of the Southern European flora (Lathyrus, 

 Nissolia, Ochrus) but especially in a large number of Australian shnibs and trees, 

 principally acacias (Acacia longifolia, falcata, myrtifnlia, armata, cultrata, Mela- 

 noxylon, decipiens, etc . ) it is the leaf -stalks which are extended like leaves placed 

 vertically, and then the development of the leaf-lamina is either entirely arrested, 

 or has the appearance of an appendage at the apex of the flat, green leaf -stalk or 

 "phyllode" as it is called."* As far as the Acacias are concerned, the appendage 

 at the apex of the "phyllodes." here referred to, is simply Bentham's seta ter- 

 minalis, or recurved point, the rudiment of an arrested terminal pinna, in which 

 the common petiole, or its distal comjionent, the rhachis, terminates. It is not, 

 as Kerner supposes, under the influence of the current dogma, that Acacia- 

 phyllodes, so-called, are simply flattened leaf-stalks or petioles, the remnant of an 

 arrested leaf-lamina. The pinnse only have been arrested, and not the rhachis 

 as well. Consequently, the tenninal seta retains its normal position at the apex 

 of the rhachis, that is, the apex of the common petiole, or the primary axis of 



•Natural History of Plants, English Edition, Vol. i., p. 335. 

 fBut see the reference to Goebel's views f>ostea, p. 44. 



