In the course of investigations aimed primarily at the isolation of alkaloid constituents, simple coumarins of known structure have been obtained from three unrelated species. These isolations are recorded as they may be of some chemotaxonomic interest, although precise yields cannot be quoted because of the extraction procedures followed. A major constituent from Pterocaulon sphacelatum B. & H., a Queensland species of the family Compositae, has been identified as 6,7-dimethoxycoumarin (I). The genus Pterocaulon of the family Compositae has received little chemical attention. Melicope melanophloia C. T. White has been found to contain negligible amounts of alkaloids, but a neutral constituent has been identified as isopimpinellin (II). Isopimpinellin has been isolated previously from other rutaceous species such as Luvunga scandens Ham., Citrus aurantifolia Swingle, and Plindersia bennettiana F. Muell. Leaves and bark of Lepiniopsis ternatensis Val. (Apocynaceae), a New Guinea species, afforded a high yield of unsubstituted coumarin. The occurrence of coumarin in this family is not unprecedented, as it has been reported to occur in the leaves of Macrosiphonia velame M.-Arg. and in the leaves and bark of Alyxia stellata Roem. & Schult.