Fig. 160. A twice-pinnate (abruptly) leaf of the Honey-Locust.
155. So the palmate leaf, if again compounded in the same way, becomes twice palmate, or, as we say when the divisions are in threes, twice ternate (in Latin form biternate); if a third time compounded, thrice ternate or triternate. But if the division goes still further, or if the degree is variable, we simply say that the leaf is decompound; either palmately or pinnately decompound, as the case may be. Thus, Fig. [161] represents a four times ternately compound (in other words a ternately decompound) leaf of a common Meadow Rue.
Fig. 161. Ternately decompound leaf of Meadow Rue.
156. When the botanist, in describing leaves, wishes to express the number of the leaflets, he may use terms like these:—
Unifoliolate, for a compound leaf of a single leaflet; from the Latin unum, one, and foliolum, leaflet.
Bifoliolate, of two leaflets, from the Latin bis, twice, and foliolum, leaflet.
Trifoliolate (or ternate), of three leaflets, as the Clover; and so on.
Palmately bifoliolate, trifoliolate, quadrifoliolate, plurifoliolate (of several leaflets), etc.: or else