ACACIA SEEDLINGS. 87 



emerged, and if the latter are unable to free themselves, 

 the seedling may perhaps perish. 



The majority of Acacia cotyledons first assume a vertical 

 position, but within about a week, or less in some cases, 

 become horizontal, and may remain on the plants from two 

 to eight weeks or even longer. Those which remain vertical 

 usually fall off in about eight or ten days during the summer 

 months, but may remain longer in the winter, notably those 

 of A. neriifolia, leiophylla, salicina, and myrtifolia. A 

 feature of thin cotyledons is that within a day or two they 

 become revolute, and later, often cylindrical, after which 

 they soon fall. In some species such as, amongst others, 

 A. juniper ina, armata, suaveolens, aneura and Dawsoni, 

 the cotyledons may remain on the plant until after the 

 advent of the phyllodes. 



The cotyledons of A. stenophylla, Bidwilli, and Far- 

 nesiana are fairly fleshy while those of A. pendula and 

 aneura are slightly less so. The significance of the geo- 

 graphical distribution of the fleshy cotyledons will be 

 discussed in a later paper after more evidence becomes 

 available, but this form appears to be one which is able to 

 exist in areas where the climate is subarid, or where the 

 rainfall is confined mainly to one season of the year. 

 Primary Leaves. 



In about 400 seedlings raised, the first leaf to appear has 

 always been simply-pinnate. In a few cases, already 

 referred to, there have appeared an opposite pair of such 

 leaves. These leaves are petiolate, with stalks averaging 

 from 3 to 5 mm. long, and which emerge from the stem at 

 right angles to the cotyledons and very slightly above them, 

 the first internode often measuring scarcely *5 mm., con- 

 sequently the first leaf and the cotyledons often appear to 

 be at the same level. In the cases of A. hispidula, lelo- 

 phylla and stenophylla, the stalks are sometimes over 1 cm. 

 long. 



