INTRODXrCTIOK. 9^ 



are directed downwards, compared to an aiTOw-head ; hastate, when the 

 points diverge liorizoiitally, compared to a balbert. 



A reniform leaf is broader than long, slightly but broadly cordate at the 

 base, with rounded auricles, compai-ed to a kidney. 



In apeltate leaf, the stalk, instead of proceeding fi-om the lower edge of the 

 blade, is attached to the under surface, usually near the lower edge, but 

 sometimes in the very centre of the blade. The peltate leaf has usually 

 several principal nei-ves radiating from tlie point of attachment. 



AU the modifications of division and form in the leaf pass so gradually 

 one into the other that it is often difficult to say which term is the most 

 apphcable — whether the leaf be toothed or lobed, divided or compound, 

 oblong or lanceolate, obtuse or acute, etc. The choice of the most apt ex- 

 pression will depend on the talent of the describer. 



In their consistence, leaves or flat organs are 

 fleshy, when thick and soft ; succulent is generally used in the same 

 sense, but implies the presence of more juice. 



coriaceous, when firm and dry, or very tough, of the consistence of 

 leather. 



memiranons, when thin and not stiff. 



scariose, when very thin, more or less transparent, and not green, yet 

 rather stifi'. 



§ 6. Scales, Sracts, and Stipules. 



Scales (squamee) are leaves very much redviced in size, usually sessUe, 

 seldom green or capable of performing tlie respiratory functions of perfect 

 leaves. In other words, they are organs resembhng leaves in their position 

 on the plant, but diflPering in size, colour, texture, and functions. Tliey are 

 most frequent on the stock of herbaceous perennials, or at the base of annual 

 branches, especially on the buds of futiu-e shoots, and serve apparently to 

 protect the dormant hving germ fi-om the rigour of winter. In the latter 

 case they are usually short, broad, close together, and more or less im- 

 bricated, that is, overlapping each other like the tUes of a roof. It is this 

 arrangement, as well as their usual shape, that has suggested the name of 

 scales, borrowed from the scales of a fish. 



Sometimes, however, most or all of the leaves of the plant are reduced to 

 small scales, in which case they do not appear to perform any particidar 

 function. The name of scales is also given to any small broad flat scale-Uke 

 appendage or reduced organ, whether in the flower or any other part of the 

 plant. 



Bracts are the upper leaves of a plant in flower (those of the flowering 

 branches, or only one or two immediately under the flower), when different 

 from the stem-leaves in size, shape, colour, or arrangement. They are 

 generally much smaller and more sessile. They often j)artake of the colour 

 of the flower, although they very frequently also retain the green colour of 

 the stem-leaves. When small they are often called scales. 



Floral leaves or Leafy hracts are generally the lower bracts, or the upper 

 leaves at the base of the flowering branches, intermediate in shape, size, or 

 arrangement, between the stem-leaves and the upper bracts. 



Bracteoles are the one or two last bracts under each flower, when they 

 differ materially in shape, size, or arrangement from the other bracts. 



Stipules are leaf-like or seale-Uke appendages at the base of the leafstalk, 

 or on the node of the stem. Wlien present there are generally two, one on 

 each side of the leaf, and they sometimea appear to protect the young leaf 



