Definition of "jhow"

The river remains most uninteresting: the banks are low and covered chiefly with Jhow.

1847, William Griffith, Journals of travels in Assam, Burma, Bootan, Affghanistan and the Neighbouring Countries, page 318

It is very abundant in Bengal, in many parts near the foot of the Himalayas, in Deyra Doon, and near the Ganges, Jumna, Sutlej, and other large rivers, frequenting chiefly long grass and jhow jungle.

1984, Thomas Claverhill Jerdon, A Handbook of the Mammals of India, page 263

If you asked her where she learnt them, she would only laugh, her body shaking with laughter like jhow grass swaying in the wind.

2015, Arupa Patangia Kalita, translated by Ranjita Biswas, Written in Tears, Harper Perennial, page 53