The Kusanai-Jataka is #121 of the Buddhist folklore collection Jataka Tales, originally written in Pali. The #121 entry features a tree sprite in danger of losing her home within the tree known as 'Mukkhaka'. The Bodhisattva, born a sprite living in kusa-grass, helps save her home. Robert Chalmers translated the tales in 1895, and this translation remains the most prominently accessible version.
Robert Chalmers was British civil servant who studied Pali and Buddhist scripture, and member of the Pali Text Society. He received and practised extensive lessons on Pali and Buddhist text, capable of even delivering speeches in the Pali language .
Although his translatation remains the most prominent reference point, it would be disingeuous and dishonest to overlook the atrocities Chalmers had a direct hand in - specifically the 100 Days of Horror Sinalese citizens suffered under his decree of Marital Law during Britain's colonial rule of Sri Lanka, instigating inhumane brutalities against its innocent residents including murder, rape, and robbery. This article by Janaka Perera further elaborates on the atrocities that Chalmers enabled.