Master Naturalists: Nutsedge a weed with long history of consumption
By Paul and Mary Meredith
Feb. 13, 2014 at midnight
Updated Feb. 12, 2014 at 8:13 p.m.
Is nutsedge a nasty weed or an ancient Egyptian aristocratic delicacy? The answer to the question is both.
Paul reads about paleoanthropology, the study of ancient great apes found in fossil hominid evidence, bones, teeth, etc. Hominids are humans and relatives of humans closer than chimpanzees. An extinct species that has perplexed scientists is a critter, Paranthropus boisei, nicknamed "Nutcracker Man."
His fossil jaw was found in Africa in 1959 by paleoanthropologist Mary Leakey. He's called Nutcracker Man for his big, flat molars, powerful jaws and huge chewing muscles attached to a prominent skull crest. The only problem with the name? It's wrong.
Tooth wear tells a tale
Scientists concluded P. boisei did not eat hard nuts or rough savannah grasses. The Smithsonian describes the problem this way: The morphology (tooth shape) suggests a hard-food diet, but the microwear of their teeth indicates softer things. They could not explain the advantage of the big jaws and teeth. These early humans flourished for a million years, then went extinct - why?
What did he eat?
Recently, chemical isotope analysis published online on PLoS One (plosone.org) show that microscopic food remains on P. boisei's teeth were found to contain C4 plant material. C4 refers to how many carbon atoms (four) certain plants use to do photosynthesis.
Grasses and sedges use C4 photosynthesis. Scientists already knew that African savannah sedge and grass foliage would not be rich enough in energy and proteins to feed P. boisei. Then, someone checked diets of living animals. Baboons live in conditions similar to P. boisei's, and they eat an underground soft tuber of the yellow nutsedge type, commonly called the tiger nut or - in America - yellow nutsedge (yellow nutgrass).
The tubers are so nutrient-rich that anthropologists estimate P. boisei needed only to forage and dig tubers for 88 minutes a day to feed himself. Egyptologists' research on diet corroborates nutsedge as human food.
Chufa (tiger nuts) were an early food crop, remains are found in the tombs of ancient Egyptian royalty - food for the afterlife. Today, tubers are grown, dug, dried and eaten there, in Spain, in the Far East and in Central America.
Cotton or soybean farmers don't like nutsedge; U.S. Department of Agriculture classifies it as a pest in 21 crops. As for how to get rid of yellow nutsedge, herbicide control programs are not too effective. An AgriLife agent jokingly told Paul that tactical nuclear weapons worked, but they are not approved as a pesticide right now. Digging plant rhizomes, nuts and roots works, but they may be as deep as 15 inches. Leave one nut, and you will have a 47-inch circle of nutsedge in a year.
You can eat them at your place
Make sure you harvest yellow nutsedge and not purple. Yellow's tubers are sweet and nutty while purple's tubers are bitter tasting. Dig in fall, rinse, dry and store tubers in a cool place. Soak them in water to soften them or make biscuits or bread flour.
Pressed, the high-Vitamin E oil makes a great base for cosmetics. If you do decide to harvest, don't tell your neighbors; they will think you are "nuts" for sure.
Your only defense? My early relatives - very early - did the same thing.
Sources: plosone.org; Smithsonian National Museum of Natural History; Teeth Carry Clues to Diet Of the Extinct, John Noble Wilford, 1990 NY Times; nytimes.com/1990/10/16/science/teeth-carry-clues-to-diet-of-the-extinct.html; Types of Photosynthesis, Pima County Community College; pima.edu;
Paul and Mary Meredith are master naturalists. Contact them at firstname.lastname@example.org.