26 



AUSTRALIAN BOTANY. 



the year round, the leaves sometimes remaining for several 

 years. Such leaves are termed persistent. Most of the 

 native Australian plants are evergreens. Gums, Hakeas, 

 wattles, ferns, and Victorian laurel are examples. Leaves 

 differ greatly in their margins, which are of various shapes, 

 as under : — 



A, serrate or saw-edged. B, dentate 



or toothed. C, crenulate or having 



rounded marginal divisions. D, entire, 



or having an unbroken edge. Another 



J\ kind of leaf — retroserrate — has the 



teeth placed downwards instead of 



d upwards as in the serrate leaf. By 



reversing this page, A will represent a 



retroserrate leaf. The native yam has 



C this kind of leaf. 



Cauline leaves are those developed 

 Q from the stem. Ramose leaves grow 

 from the branches. Radical leaves 

 spring from so near the root as to have 

 the appearance of coming directly from 

 it. Sessile or sitting leaves have no 

 apparent foot-stalk, but appear to sit 

 directly on the branch or stem. A 

 sheathed leaf, such as is seen in most 

 grasses, has a prolongation of the leaf-stalk, which surrounds the stem. 

 Alternate leaves, as in the Rose and Camellia, grow one above the 

 other. Opposite leaves coincide or grow directly opposite each other. 

 "When more than two leaves are opposite, they are whorled {forming a 

 ring round the stem). There are other arrangements of the leaf on the 

 stem, not necessary for present mention. 



Leaves have cells containing a colouring matter, gene- 

 rally green, termed chlorophyll^ In many Australian 

 plants the leaves are turned edgeways towards the sun, as, 

 for instance, the Eucalypti or gum-trees. Stipules are small 



1 The colouring matter of flowers is not solid like chlorophyll, but 

 dissolved in the fluids of cells ; it is called ' chromuh ' or ' chromogen.' 



