IV INTRODUCTION. 



Thus, in fig. 1 6 the outline is that of a triangular leaf. The lower thinner lines 

 a a would reduce it to a deltoid, and the upper bb lo a rhombic form. 



An acute angle, geometrically, is one which is less than a right angle. Botani- 

 cally, however, the angle at a (fig. 17), which is a right angle, would be called 

 acute. There are in this respect two particulars to be noticed, for which, per- 

 haps, our botanical terms are hardly sufiicient : — whether the object described 

 terminate absolutely in an angle, and whether that angle be obtuse or acute. 

 Rounded at the end is sometimes employed to express a form where the angle is 

 not quite completed, and sometimes where a semicircle is formed on nearly the 

 whole width of the leaf. I have rather avoided the term, unless where the 

 context limits the meaning. Attenuate, when used alone, indicates with me a 

 form narrowed at the base and somewhat prolonged, exactly corresponding with 

 acuminate at the summit. Attenuate at both ends is attenuate and acuminate. 

 I find sometimes a distinction between attenuate and acuminate, both as applied 

 to the summit of a leaf ; but I do not know what is meant by it ; nor have 1 any 

 distinct idea of what is intended by acutatus, a word frequently introduced by 

 Kunth. De CandoUe sometimes uses the word acuminate where there is no 

 reversed curvature, and where I have employed the expression j/?weZj' acute. 



Besides these limitations of meaning in words generally adopted, I have intro- 

 duced two or three not usual in botanical descriptions. One of these \s> prolonged, 

 as applied to mark a form differing from acuminate by a prolongation of the upper 

 part of the leaf without any reversed curve. Thus the shortest and bluntest 

 form (fig. 15) I call simply cordate; with the little point above, it becomes 

 cordate, acute ; with the inner prolongation, it is cordate, acuminate ; and with the 

 outer, cordate, prolonged. In like manner, the inner thin line at the base is 

 cordate, attenuate ; the second would make the stalk become a haft ; and where 

 the membranous margin is wider, the leaf becomes spatulato-cordate. 



The word Haft, used in the above sentence, I employ to denote a leaf-stalk 

 accompanied by a membranous margin. Such a stalk is sometimes said to be 

 winged, and sometimes is considered as making part of a spatulate leaf. Some 

 genera, and even some natural orders, have no true leaf-stalk, and what has been 

 usually so called is properly a haft. 



Oval and lanceolate are forms alike, or nearly alike, at each end {de minimis 

 non curat botanicus), ovate and cordate are not so ; and hence the use of the 

 words obovate and obcordate where the greatest breadth is upward. Bertoloni 

 uses the expressions ohversely lanceolate and obversely oblong, meaning apparently 

 a lanceolate or oblong leaf, of which the widest part is a little above the middle, 

 yet not so much so as to be called obovato-lanceolate or obovato-oblong. The 

 reader may, perhaps, find this term preserved in descriptions taken from the 

 ' Flora Italica,' 



