xx OUTLINES OF BOTANY. 
more or less prolonged into an acumen or point, which may be acute or ob- 
tuse, linear or tapering. Some botanists make a slight difference between 
the acuminate and cuspidate apex, the acumen being more distinct from the 
rest of the leaf in the latter case than in the former; but in general the 
two terms are used in the same sense, some preferring the one and some 
the other. 
truncate, when the end is cut off square. 
retuse, when very obtuse or truncate, and slightly indented. 
emarginate or notched, when more decidedly indented at the end of 
the midrib; obcordate, if at the same time approaching the shape of a 
heart with its point downwards. 
mucronate, when the midrib is produced beyond the apex in the form 
of a small point. — 
aristate, when the point is fine like a hair. 
48. The base of the leaf is lable to the same variations of form as the 
apex, but the terms more commonly used are tapering or narrowed for acute 
and acuminate, sounded for obtuse, and cordate for emarginate. In all cases 
the petiole or point of attachment prevents any such absolute termination 
at the base as at the apex. 
49, A leaf may be cordate at the base whatever be its length or breadth, 
or whatever the shape of the two lateral lobes, called awricles (or little ears) 
formed by the indenture or notch; but the term cordiform or heart-shaped 
leaf is restricted to an ovate and acute leaf, cordate at the base, with 
rounded auricles. The word ‘auricles’ is more particularly used as applied 
to sessile and stem-clasping leaves. 
50. If the auricles are pointed, the leaf is more particularly called aurz- 
culate; it 1s moreover said to be sagittate, when the points are directed 
downwards, compared to an arrow-head; hastate, when the points diverge 
horizontally, compared to a halbert. 
51. A reniform leaf is broader than long, slightly but broadly cordate 
at the base, with rounded auricles, compared to a kidney. 
52. Ina peltate leaf, the stalk, instead of proceeding from 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 nerves radiating from the point of attachment, 
being, in fact, a cordate leaf with the auricles united. 
58. All these modifications of division and form in the leaf pass so gra- 
dually one into the other that it is often difficult to say which term is the 
most applicable—whether the leaf be toothed or lobed, divided or com- 
pound, oblong or lanceolate, obtuse or acute, ete. The choice of the most 
apt expression will depend on the skill of the describer. 
54. Leaves, when solid, Stems, Fruits, Tubers, and other parts 
of plants, when not flattened like ordinary leaves, are 
setaceous or capillary, when very slender like bristles or hairs. 
acicular, when very slender, but stiff and pointed hke needles. 
subulate, when rather thicker and firmer like awls. . 
linear, when at least four times as long as thick ; oblong, when from 
about two to about four times as long as thick, the terms having the same 
sense as when applied to flat surfaces. 
ovoid, when egg-shaped, with the broad end downwards ; obovoid, if the 
broad end is upwards: these terms corresponding to ovate and obovate 
shapes in flat surfaces. 
