PLANT ORGANS AND ORGANISMS 165 
Repand, or Undulate, margin—a wavy line. Example: Hama- 
melis. 
Sinuate, when the margin is more distinctly sinuous than the last. 
{Stramonium.) 
Incised, cut by sharp, irregular incisions. Example: Hawthorn. 
Runcinate, the peculiar form of pinnately incised leaf observed in 
the Dandelion and some other Composite in which the teeth are 
recurved. 
A Lobed leaf is one in which the indentations extend toward the 
mid-rib, or the apex of the petiole, the segments or sinuses, or 
both, being rounded. Example: Sassafras. 
Cleft is the same as lobed, except that the sinuses are deeper, and 
commonly acute. Example: Dandelion. 
A Parted leaf is one in which the incisions extend nearly to the 
mid-rib or the petiole. Example: Geranium maculatum. 
In the Divided leaf the incisions extend to the mid-rib, or the 
petiole, but the segments are not stalked. Example: Watercress. 
If the venation is pinnate, the preceding forms may be described 
as pinnately incised, lobed, parted, or divided. If the venation is 
radiate, then the terms radiately or palmately lobed, incised, etc., 
are employed. 
The transition from Simple to Compound Leaves is a very gradual 
one, so that in many instances it is difficult to determine whether a 
given form is to be regarded as simple or compound. The number 
and arrangement of the parts of a compound leaf correspond with 
the mode of venation, and the same descriptive terms are applied 
to outline, margin, etc., as in simple leaves. 
Leaves are either pinnately or palmately compounded. The term 
pinnate is frequently given to the former while that of palmate is 
often assigned to the latter. They are said to be abruptly pinnate 
or paripinnate when the leaf is terminated by a pair of leaflets; odd 
pinnate or imparipinnate when it terminates with a single leaflet. 
When the leaflets are alternately large and small, the leaf is inter¬ 
ruptedly pinnate, as the Potato leaf. When the terminal leaflet is 
the largest, and the remaining ones diminish in size toward the base 
the form is known as lyrate, illustrated in the leaf of the Turnip. 
Palmately compound leaves have the leaflets attached to the 
