Here's where they describe the "grasses and sedges" of Paleo days:
The authors argue that it is unlikely that the hominins would have eaten the leaves of the tropical grasses as they would have been too abrasive and tough to break down and digest. Instead, they suggest that these early hominins may have relied on the roots, corms and bulbs at the base of the plant. http://www.ox.ac.uk/media/news_releases_for_journalists/121112.html
One such food may have been certain African yams: "Aftrican yams have probably been a source of food for humans since time immemorial and were very likely also eaten by their hominid ancestors." (Biodiversity and Domestication of Yams in West Africa: Traditional Practices Leading to Dioscorea rotundata Poir. Roland Dumont, Alexandre Dansi, Philippe Vernier, Jeanne Zoundjihèkpon, 2006)
Here are some yams (Dioscorea) that are edible raw:
> Dioscorea bulbifera - the "air potato"/"potato yam" (native to Africa and Asia; apparently only certain varieties are edible raw per
http://en.wikipedia.org/wiki/Yam_(vegetable); http://tiny.cc/t89pow)
> Dioscorea transversa - Long Yam or Parsnip Yam--native to Australia;
Women Hunters - Ray Mears Extreme Survival - BBC > Dioscorea batata (opposita; nagaimo; Chinese yam; yamaimo) - Mountain Yam (native to China;
http://en.wikipedia.org/wiki/Yam_(vegetable))Those aren't commonly found in stores, but there are other storage organs that are edible raw, some of which I've discussed in the past.
