president's address. 39 



species is an exceptioual one, in need of special investigation. It is a species 

 which I have not had the opportunity of e.xamining. A. lonyi folia is much in- 

 fested by borers, and one can iind plants which have l)een broken by people in 

 getting the flowers, but I have never met with revei-sion-foliage. Seedlings of .-1. 

 falcata are often so badly attacked by insect gall-makers, that the growing point 

 may be killed, but I have not found that it induces the production of reversion- 

 foliage. Plants of A. myrti folia often show a disorganised production of crowd- 

 ed euphyllodes, apparently due to fungoid attacks, but I have failed to find re- 

 version-foliage . 



Quite the most satisfactory species for foliage vt tiiis kind is A. suaveolens, 

 because one can get it in abundance. Adxanced seedlings up to 5 feet high, seem 

 to be particularly liable to fungoid attacks, which sometimes seriously interfere 

 with, or e\-en kill the growing-point, often resulting in large excrescences of ab- 

 noiTiial growth on the summit. If this happens, not too close to the ground, 

 it frequently results in an outburst of reversion-foliage along a portion of the 

 stem, or on the proximal portions of any branches that may be present. This 

 will often supi)ly most instructive stages in the transition from bininnate leaves 

 to euphyllodes, whicli are not shown in normal seedlings. 



Eleven examples of remarkable leaves (nat; size) are shown in Plate i. These 

 are of interest because, in addition to the ordinary apical pair of pinna, or this 

 and the second ])air next below it, some of them show pairs of reduced pinnae, or 

 single reduced jiinna'. ]>airs of leaflets or single leaflets, at different levels, on the 

 margin of the developing euphyllode or half-euphyllode, instead of on the mid- 

 rib; other's show foliaceous terminal setae; and two have three leaves at a node. 

 Figs. 1, 3, and 11 have no or but slight development of the lower side of the 

 euphyllodes. All three have an odd pinna below the first jsair of iiinnse, or just 

 below the second pair (the leaflets missing in Fig. 3); and, at a lower level, 

 a pair of pinnae with a reduced numlier of leaflets, on tlie margin of the euphyl- 

 lode. A. suaveolens is remarkable in this respect, namely, for the transference of 

 the leaf -buds to the margin of the eujihyllode, instead of their remaining on the 

 midrib . 



Figs. 2 and 6 show two pairs of pinnae (one pinna missing in Fig. 0) and a 

 single, small pinna, with but few leaflets, on the edge of the euphyllode. They 

 are figured especially to show, what I have seen only in the reversion-foliage of 

 this species, in which it is common — the occurrence of three leaves at some of the 

 nodes, of which the middle one is always the most developed. In the examples 

 given, the two lateral leaves of the trio are simjjly pinnate. But, sometimes, one 

 or both may be bipinnate ; or the middle one may be a complete large euphyllode, 

 while one, at least, of the lateral ones may be a smaller euphyllode. The two 

 lateral leaves probably develop from reserve-buds. Lubbock describes and figures 

 a seedling of ^1. i-erticillata, of which the sixtli leaf was represented by a single 

 euphyllode. but some of the succeeding ones by broken or complete whorls of 

 euphyllodes. Other species may also have whorled or verticillate or grouped 

 euphyllodes; but, as far as I know, nothing analogous to it is known in bipinnate 

 Acacias. Fig. 2 shows the terminal seta; and the retarding effect of the pre- 

 sence of the second jiair of pinn^ on the flattening of the internode, and for some 

 distance below. 



Figs. 4, 5, and 7 show a pair of leaflets, or two odd leaflets, on the margins of 

 the euphyllode at different levels. Sometimes a jiinna, or a leaflet or leaflets, 

 may be quite close to the base, indicating that the petiolar portion of the euphyl- 



