What's the plural form of bristlegrass? Here's the word you're looking for.
Answer
The noun bristlegrass can be countable or uncountable.
In more general, commonly used, contexts, the plural form will also be bristlegrass.
However, in more specific contexts, the plural form can also be bristlegrasses e.g. in reference to various types of bristlegrasses
or a collection of bristlegrasses.
