I can't really tell what species this is from the images without the seed head. Is there anything you noticed in the field that led you Microlaena for this one?
@MattM I saw some old inflorescence stems that looked right for it -- photo has now been attached. It was also kind of based on vibes and way it was growing - preferring sheltered positions and more dried out in the sun, and growing in those mat-like mounds.