Buckshorn plantain: the strange green stuff on the top of a salad

Steamed hake with buckshorn plantain, reedmace and
sorrel butter. Taken from here. 

I never heard of buckshorn (pronounced bucks-horn) plantain , until Jeremy Cherfas posted about it on Facebook. But I've unknowingly eaten it as the unidentified green stuff garnishing sophisticated salads. While native to the Old World, this salad green has been grown in the United States for several hundred years. Today, buckshorn plantain (Plantago coronopus) is often known as “minutina” or “herba stella”. The plant’s common name is derived from the shape of its leaves: narrow, spiky and antlerlike.  Buckshorn plantain can be harvested as a wild salad, or bought in higher-end vegetable markets. Read more about buckshorn plantain here.