When scratched, it yields a black streak.
Crop yields are highly volatile and unpredictably so.
Beetroot (Beta vulgaris) is used as fodder, and yields about 10 tons per acre.
In the former case the nature of the organism is such that it yields readily, when subjected to certain conditions, and all or nearly all the individuals become modified in the same way.
Amongst arboreous families Leguminosae and Euphorbiaceae are prominent; Hevea belonging to the latter is widely distributed in various species in the Amazon basin, and yields Para and other kinds of rubber.
