INTRODUCTION 
Arrow-head ; and in Birch and Poplars we have examples of rhomboid 
leaves, approximately four-sided, with acute angles at the base and apex 
and obtuse ones at the sides. Even with all this terminology many 
intermediate forms are found, for which we have to combine two terms, 
ovate-lanceolate , for instance, being a very frequent outline. There is 
always a considerable range of variation in the leaves of any one plant ; 
and when cauline and radical leaves occur on the same plant, as in the 
Shepherd’s-purse, they generally differ considerably in form ; but 
the term heterophyllous is specially applied to plants, like some of the 
Water-crowfoots, the Arrow-head, and others, in which two or more 
markedly different types of leaf, such as broad floating ones and 
decompound or narrow ribbon-like submerged ones, occur on the 
same plant. 
The apex of a leaf may be rounded or obtuse , as in the Oak ; acute, as 
in the Rose ; acuminate , or narrowing suddenly into a long tapering point, 
as in Nettles ; or ob-cordate , reversedly heart-shaped, as in 
the leaflets of the Wood-sorrel. In describing compound 
leaves, the leaflets, after their number and arrangement have been 
mentioned, are treated as simple leaves would be. 
The surface of the leaf is described by the same terms as are used for 
herbaceous stems. It may be glabrous , or free from hairs, as in the Spindle- 
tree ; g/abrescent , or hairy when young, becoming smooth 
later, as in the Beech ; pubescent or downy, with numerous 
short hairs, as in Sage ; or silky, with long hairs, as in the under surface of 
the leaves of the Alpine Lady’s-mantle. Careful note should always be 
taken of the hairs on plant-surfaces, whether they are in lines, or confined 
to the margin of the leaf or the forkings of its veins, to its under or upper 
surface ; whether they lie flat or adpressed to the surface, or spread outwards ; 
whether they are stellate or star-shaped, or tipped with rounded glandular 
ends. One very striking character of surface is the blue-grey, or glaucous, 
coating of minute wax-particles characteristic of a large number of 
sea-shore plants, such as Cabbages, Sea-Kale, Sea-Poppy, Sea-Holly, 
Carnations, etc. 
Apex 
Surface 
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