34 president's address. 



the leaf. But that Kerner should be the only author, so far as I can learn, to 

 liave recognised the occurrence of an apical, vestigial structure on the so-called 

 phyllodes of the Australian Acacias, is both surprising and interesting. His 

 mistake, like the mistakes of others, was attributable to a lack of adequate ma- 

 terial for study. Nevertheless, his obseixation is notable. 



The meaning and significance, and in some cases the occu.Tcnce, of the ter- 

 minal seta or recur\ed or excurrent point, or rudiment of tiie terminal pinna, 

 of the leaves of the Australian Acacias, whether in the seedling-stage or otherwise, 

 have received such scant eonsideratiou from authors, that a comparison of the 

 leaves of Acacias with those of other genera with remarkable bipinnate leaves is 

 not only very instructive, but wliat can be learned in this way needs to be em- 

 phasised and allowed for. 



For comparative purposes, the most satisfactory material is afforded by the 

 leaves of three plants belonging to exotic genera, more or less common in gardens 

 in Sydney. I am unable to find anything about them in any books available to 

 me, from the particular standpoint in which T am interested in them. These 

 are Caesalpinia GiUiesil Wall., native of La Plata States, which is of interest 

 because the leaves have a terminal pinna, but the i)inn» lack a terminal leaflet ; 

 Jacaranda ovali folia R.Br., native of Brazil, which is remarkable because the 

 leaves have a fugacious terminal pinna which is wanting in the mature leaves, the 

 pinnas have a terminal leaflet, and the mode of succession of both the pinnae and 

 the leaflets in the development of the bipinnate leaf is basifugal; and the West 

 Indian Calliandra portoricensis, whose leaves, like those of the bipinnate Acacias, 

 have neither a terminal pinna, nor have the pinna? a terminal leaflet; but, in both 

 cases, especially in the young leaves, vmless it is accidentally missing, the ter- 

 minal setae are conspicuous. 



C. Gilliesii has leaves up to nearly 7 inches long, to the base of the terminal 

 pinna; witli twelxe or thirteen pairs of short pinnae, with about eight to ten pairs 

 of leaflets. As in the Acacias, the leaves present anomalies. Some of the pinnae 

 are alternate instead of opjjosite; one of a pair is sometimes missing; the ter- 

 minal pinna is occasionally missing; the number of pairs of leaflets of tiie idnnai 

 is variable. The leaves show: — (1) that the internodes are about as long as the 

 spread of an expanded pair of leaflets, measured from tip to tip across the partial 

 rhachis; (2) that the pinnae of the lower pairs are fairly at right angles to the 

 axis, but that the ajiical pair and several paire next below do usually move in- 

 wards slightly, so that there may be some slight overlapping of the lower leaflets 

 of the ajiical pair and the terminal pair, even though the latter has a longer 

 petiole tlian the others; (3) and that the petiole uuiy lie no longer tlian tiie lowest 

 internode, or half as long again ; but however mucli it may be. it is liut a small 

 fraction of the length of the entire axis or conmion [letiole. Fig. 1 of PI. iii.. 

 represents the upper portion of a leaf, in which the pinna? of the apical \r.\\v 

 are at right angles to the .axis; and this was chosen for illustration because the 

 terminal pinna was fully displayed. Lubbock figures a very young seedling of 

 this species, with only the first leaf, which is nliru|illy lunnatc. but no I'urthcr ]iar- 

 ticulars are given . 



The longest .Tacai'anda leaf that 1 liavc, without (lortion of the ti]), which is 

 missing, is 211 inches long, petiole 2if, with .32 pairs of pinna\ some of which 

 are alternate. Longer leaves may be seen on some trees. Mature leaves rarely 

 show anything at the ajicx, but the basal scar of something which is missing. 1 

 figure a small leaf from a young plant Si inches long, which should have eighteen 

 pairs of ])inna' and a terminal ))inna: l)ut tlic terminal i>inna, and four pairs of 



