ACACIA SEEDLINGS. 



89 



leaf is simply-pinnate, viz., those of A. juniperina, (Plate 

 VIII, No. 1), though a few others have appeared so, owing 

 to one of the pinnae not having developed or having fallen 



off. In all these cases the first leaf 

 has been simply-pinnate, so that 

 the generally-accepted view that 

 the ancestors of the present 

 Acacias had simply-pinnate leaves 

 seems correct. This being so, it 

 is perhaps not remarkable that 

 the simply-pinnate leaf should 

 sometimes reappear among the 

 seedling foliage, and with ex- 

 tended search, many more exam- 

 Fig, l. Acacia suaveoiem. pies among various species will 



Cotyledons and primary leaf. x2. probably be found. 



Bipiimate Leaves. 

 Next after the pinnate leaf, or in some cases the opposite 

 pair of pinnate leaves, come the bipinnate leaves, arranged 

 alternately; the common petioles usually becoming longer 

 for each succeeding leaf. The leaflets much resemble those 

 of the pinnate leaf. In some instances one of the pinnae 

 may be broken off, or may not properly develop, and unless 

 care be exercised in the observations, the leaf may perhaps 

 be regarded as simply-pinnate. Often, however, some 

 slight portion of the absent pinna or the excurrent point 

 of the common petiole remains as evidence of the previous 

 state of the leaf. In certain species, however, including 

 A, aidacocarpa, the second and third leaves may commonly 

 develop with only one pinna, but with the excurrent point 

 of the petiole quite distinct, and no definite evidence of 

 even the rudiments of the second pinna. These appear to 

 be examples of a transition stage which will be referred to 

 when more data are available, and should rather be 



