vi “INTRODUCTION TO BOTANY. 
Leaves are,- : : 
oblong (or broadly-linear) when 2-4 times as long as broad, with sub-parallel 
sides and blunt extremities ; 
ovate, when about twice as long as broad, broader below the middle, or 
shaped like the longitudinal section of an egg ; obovate is the same form 
reversed, the narrow end being at base. 
orbicular or rotund, when approaching to a circular form. 
oval or elliptical, when broadest in the middle, with curved sides, like an 
ellipse or oval. 
transversely-oblong or oblate, when conspicuously broader than long. 
rhomboidal or rhomboid, when shaped like the mathematical figure called 
a vhombus. 
falcate, shaped like a scythe, curved with nearly parallel sides and a sharp 
int. 
44, cede forms are expressed by combining two terms. Thus, a linear- 
lanceolate leaf is long and narrow, yet rather broader below the middle and tapering 
toa point; ovato-lanceolate is broad towards the base, yet tapering towards the 
apex, &c. ; 
45. The apex or summit of a leaf is, 
acute or pointed, when it is sharp, or forms an acute angle, 
obtuse or blunt, when it forms an obtuse angle or oftener is rounded. 
acuminate, when suddenly narrowed near the top and then prolonged into an 
acumen or projecting point, which may be acute or obtuse, linear or 
tapering ; euspidate is either synonymous with acuminate, or else used to 
express a more exaggerated degree of acumination, with a more sudden, 
sharper, and more rigid point. 
truncate, when the end is cut off nearly square. 
retuse, when very obtuse or truncate, and slightly indented in the middle ; 
a or notched, when more decidedy indented at the end of the mid- 
TID ; 
mucronate, when the mid-rib is produced beyond the apex in the form of a 
“small point ; mucronulate when it projects very little. 
aristate, when the point is long and fine, like a bristle. 
46. The base of the leaf is liable to the same variations of form as the apex, but — 
the terms commonly used are tapering or narrowed for acute and acuminate ; 
rounded for obtuse ; and cordate for emarginate, But the term cordiform, cordate or 
heart-shaped leaf is restricted to an ovate and acute leaf, cordate at base, with 
rounded auricles; and obcordate to an obovate, deeply emarginate or sub-bilobed 
leaf or leaflet, with rounded lobes. The word awricle is more strictly applied to the 
prolonged base of sessile, and stem-clasping leaves. 
47. If the awricles (46) are pointed, the form is said to be sagittate when the points 
are directed downwards, as in the head of an arrow; hastate, when the points di- 
verge horizontally, compared to a halbért. 
48. A reniform leaf is broader than long, very obtuse at apex, slightly but broadly 
cordate at base, with rounded auricles, compared to a kidney. 
49. In a peltate leaf, the stalk, instead of proceeding from the lower edge of the 
blade, is attached to the under surface, often near the lower edge, but sometimes in 
the very centre of the blade ; the nerves radiate from the point of attachment of the 
ey or proper base of the leaf. It is structurally a cordate or — leaf 
Ww. auri are uent B . . : in a 
sintlor coatinen confluent ; just as a perfoliate leaf (35) is the amplexicaul, 
50, In their consistence, leaves or other flat organs are 
Aleshy, when thick and soft ; succulent is generally applied in the same sense, 
BOT oly 
: 8, Or y W. and or he: 
Y ees tence very tough ; 
* 
scariou, wa gaapeer when very thin, more or less transparent, and not green, 
51, Solid leaves (or stems, fruits, seeds, or other parts of plants not flattened) 
are fe 
acerose or acicular, very slender, like needles 5 
