I thought this reddish-brown plant that grows here and there throughout the park was amaranth, an important source of calories and beverages for the indigenous people of South America before the conquest. But to be sure, I took a photo to Berkeley Hort, where the staff of trained botanists know just about everything that grows, and botanist Ivy quickly set me straight. This plant is not amaranth, it is Rumex Crispus, otherwise known as Curly Dock or Dock Weed. The new leaves of the young plant can be eaten sparingly in a salad, and there are reports that indigenous Americans had varied medicinal uses for extracts of the root. But the seeds, which the plant displays invitingly, don’t seem to have figured positively in anyone’s diet. The plant is listed on the Food and Drug Administration’s poisonous plant list, and the veterinary literature reports cases of sheep and also humans who died after ingesting the mature plant. Twelve US states list it as a noxious weed, and it’s considered an “injurious weed” in the UK. Like several other common Cesar Chavez Park plants, it’s often seen in disturbed soil and can be invasive. Probably the only reason it’s not more widespread in the park is that other, even more aggressively invasive species have outcompeted it.