A characteristic feature of the liverwort cell is the presence of “oil bodies”. Chemically they are made up of rather volatile terpenoids, mainly sesquiterpenes and their derivatives (Suire 1975) which seem to be surrounded by a membrane. The nature of this membrane is still unknown. Through the light microscope the oil bodies appear as colourless, rarely brownish or blueish organelles in the cytoplasm, showing great variation in shape, size, number and structure. The morphological characteristics of the oil bodies, which have been studied over 80% of the genera of Hepaticae, have been shown to be taxonomically significant (cf. Schuster 1966). While in the subclass Marchantiidae they are restricted to special, chloroplast-free “oil cells” of the gametophyte, in the remaining groups (subclass Jungermanniidae) they are abundant in the green cells of gametophyte and sporophyte. In the course of our investigations on tropical American liverworts we recognized four morphological types (Gradstein et al. 1977): 1) Massula type – oil bodies homogeneous, small (2-6 μm) and numerous, in median leaf cells more than 8 per cell. 2) Bazzania type – oil bodies homogeneous, large (4-15 μn long) and few, up to 8 per cell. 3) Jungermannia type – oil bodies finely segmented, consisting of numerous minute, indistinct globules surrounded by a common membrane. Size and number variable. 4) Calypogeia type-oil bodies coarsely segmented, consisting of distinct globules aggregated to form a “grape-cluster”; a common membrane seemingly lacking. Size and number variable.