126 
PHARMACEUTICAL BOTANY 
mid-vein, or mid-rib, as it is usually called, 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. Example: Geranium maculatum. 
In the Divided leaf the incisions extend to the mid-rib, 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 
apex of the petiole. When these are two in number the leaf is 
bifoliate, or binate; if three in number, trifoliate, or ternate; when 
four in number, quadrifoliate, etc. If each of the leaflets of a pal- 
mately compound leaf divides into three, the leaf is called biternate; 
if this form again divides, a triternate leaf results. Beyond this 
point the leaf is known as decompound. In the case of pinnately- 
compound leaves, when division progresses so as to separate what 
would be a leaflet into two or more, the leaf becomes bipinnate, 
as the compound leaves of Acacia Senegal or on the new wood of 
