OUTLINES OF BOTANY. XV1L 
34, A culm is a name sometimes given to the stem of Grasses, Sedges, 
and some other Monocotyledonous plants. 
§ 5. The Leaves. 
35. The ordinary or perfect Leaf consists of a flat blade or lamina, 
usually green, and more or less horizontal, attached to the stem by a stalk 
ealled a footstalk or petiole. When the form or dimensions of a leaf are 
spoken of, it is generally the blade that is meant, without the petiole or 
stalk. 
36. The end by which a leaf, a part of the flower, a seed, or any other 
organ, is attached to the stem or other organ, is called its base, the op- 
posite end is its apex or summit, excepting sometimes in the case of anther- 
cells (115). 
37. Leaves are 
sessile, when the blade rests on the stem without the intervention of 
a petiole. 
amplexicaul or stem-clasping, when the sessile base of the blade clasps 
the stem horizontally. 
perfoliate, when the base of the blade not only clasps the stem, but 
closes round it on the opposite side, so that the stem appears to pierce 
through the blade. 
decurrent, when the edges of the leaf are continued down the stem so 
as to form raised lines or narrow appendages, called wings. 
sheathing, when the base of the blade, or of the more or less expanded 
petiole, forms a vertical sheath round the stem for some distance above the 
node. 
38. Leaves and flowers are called radical, when inserted on a rhizome 
or stock, or so close to the base of the stem as to appear to proceed from 
the root, rhizome, or stock; cawline, when inserted on a distinct stem. 
Radical leaves are rosulate when they are spread in a circle on the ground. 
09. Leaves are 
simple and entire, when the blade consists of a single piece, with the 
margin nowhere indented, simple being used in opposition to compound, 
entire iu opposition to dentate, lobed, or divided. 
ciliate, when bordered with thick hairs or fine hair-like teeth. 
dentate or toothed, when the margin is only cut a little way in, into 
what have been compared to teeth. Such leaves are serrate, when the teeth 
are regular and pointed like the teeth of a saw; crenate, when regular and 
blunt or rounded (compared to the battlements of a tower) ; serrulate, and 
crenulate, when the serratures or crenatures are small; sinwate, when the 
teeth are broad, not deep, and irregular (compared to bays of the coast) ; 
wavy or undulate, when the edges are not flat, but bent up and down (com- 
pared to the waves of the sea). 
lobed or cleft, when more deeply indented or divided, but so that the 
incisions do not reach the midrib or petiole. The portions thus divided 
take the name of Jobes. When the lobes are narrow and very irregular, 
the leaves are said to be laciniate. ‘The spaces between the teeth or lobes 
are called sinuses. 
_ divided or dissected, when the incisions reach the midrib or petiole; but 
the parts so divided off, called segments, do not separate from the petiole, 
even when the leaf falls, without tearing. 
compound, when divided to the midrib or petiole, and the parts 
a 
