PPLES AND ORANGES have long been held to be analytically incommensurable. Whether stated in quantitative terms (how does one add apples and oranges?) or in qualitative terms (which taste better, apples or oranges?), the dilemma remains largely unresolved, and much of comparative analysis is consequently reduced to comparative anatomy i.e., the mere description and collation of structural properties. While the use of analogy is always somewhat misleading, certain similarities may be noted when anatomically diverse political party systems are substituted for anatomically diverse edible friuts. In purely morphological terms, comparison between, say, competitive multi-party systems and dominant one-party systems has much in common with comparison between apples and oranges: On the one hand, the ostensible disparity in the physical properties of the objects under consideration tends to be conducive to an oversimplified view of their structural uniqueness, thereby reinforcing the notion of incommensurability; ' on the other hand, there is likely to be a tendency to impute broad functional significance to certain superficial structural resemblances, thereby conducing to the adoption of arbitrary (and often misleading) analytical categories.2 The object here is not needlessly to denigrate the utility of morphological comparison. Rather, it is to point out the necessity for the inclusion of two additional dimensions of comparison the ecological and the developmental alongside the more obvious structural dimension. To illustrate this contention, we shall examine two divergent political party systems the Ghanaian and Indonesian which by all anatomical standards are as dissimilar (and hence theoretically as incommensurable) as apples and oranges, yet which exhibit certain ecological and developmental properties of social formation which render them fit subjects for inclusion within a single comparative framework.3