240 PHARMACEUTICAL BOTANY 
When the lobes or divisions of a pinnately-divided, -parted 
or cleft leaf are alternately large: and small, the leaf is inier- 
ruptedly pinnate, as the Potato leaf. When the terminal lobe is 
the largest, and the remaining ones diminish in size toward the 
base the form is known as /yrate, illustrated in the leaf of the 
Turnip. | 
Compounp LEAvEs.—The transition from Simple to Com- 
pound 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. 
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, ér2folzate, or ternate, as in 
Menyanthes; when four in number, quadrifoliate, as in four-leafed 
clover, etc. If each of the leaflets of a palmately 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 the Honey Locust 
(Gleditschia); if these become again divided, as in many Acacia 
species, the leaf is termed tripinnate. Beyond this point the leaf 
is known as decompound. Examples of pinnately-decompound 
leaves are seen in Cimicifuga and Parsley. 
Lear Moprrications.—The leaves of a number of plants have 
become modified in one or more parts for the purpose of carrying 
out special functions coincident with habits acquired by the 
plants possessing them. Thus, in the common Garden Pea, the 
