INTRODUCTION 
Outline 
the leaf is called hastate , or halberd-shaped. It is practically by a 
growing together, or simultaneous expansion, of the auricles of rounded 
petiolate leaves that the striking shield-shaped, or peltate , leaves (Latin 
peltis , a shield) of the plants known in consequence as Pennyworts are 
produced, in which the stalk springs apparently from the centre of the 
under surface. 
Of the large number of terms by which botanists endeavour to 
express definitely and concisely the wellnigh infinite variety of the 
general outline of leaves, i.e. the relations of their 
margins, the following are the chief. With straight, 
parallel sides, leaves may be acicular , or needle-shaped, as in Pines, 
when they are generally many times longer than they are broad, but not 
much broader than they are thick, and are hence prismatic in cross- 
section ; linear , with some appreciable width, but at least four times as 
long as they are broad, as in Lavender, Iris , and Grasses ; or oblong , 
not more than four times as long as they are broad, as in the floating 
leaves of some Pond-weeds. With rounded sides and widest across the 
middle, leaves may be oval , if more than twice as long as they are 
broad, as in the Butterworts ; elliptical , if less than twice as long as they 
are broad, as in the Apple ; or round or orbicular , as in the Water- 
lilies and Pennyworts. If widest near their base, leaves may be lanceolate , 
if at least four times as long as they are broad, as in the Creeping Willow 
( Salix repens) and some other species of the genus Salix ; ovate , if 
little more than twice as long as they are broad, as in the Pear ; or 
reniform , or kidney-shaped, broader than they are long, as in Ground-ivy 
( Nepeta hederacea). If widest near the apex, leaves may be spathulate or 
spoon-shaped, rounded above and attenuate at the base, as in the Daisy ; 
ob-lanceolate , i.e. reversedly lanceolate and, therefore, at least four times 
as long as they are broad, as in the Ribwort Plantain ; or ob-ovate, 
similarly not much more than twice as long as they are broad, as in the 
Cowslip. Deltoid leaves, such as those of the Danish Scurvy-grass 
( Cochlearia danica ), approximate to an equilateral triangle ; while the term 
triangular is applied to such longer or isosceles forms as those of the 
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