Edit: Here's a more vegetable related one. Apparently Moctezuma sent rather sinister people to the first dinner he provided for the Spanish. They were sent to test the Spanish. The first round of food he provided was sprinkled with blood which the Spaniards spat out. This was rather wise, Knab argues, since the sinister people were actually witches and were well versed in being able to poison people or transmit sicknesses. The second meal contained a cacophony of foods, some of which were not supposed to be eaten together. These things include pipilo, an herb, tlachicaztli, a sweet grass, as well as camotes, sweet potatoes, zapotes, acidic fruits, guajes, and cactus fruits. Eating all of these things together would produce extreme gastrointestinal distress and could have been a way to cripple the Spanish if Moctezuma's had ordered his fifth column to attack them after their meal.

Not really a vegetable, but the Tecuexes of Jalisco, Mexico produced two notable beverages, chianpinole and huanpinole (Baus Czitrom 1985). Chianpinole is made out of Salvia hispanica or more commonly known as chia. The huanpinole was made from huatli (Amaranthus leucocarpus). Unfortunately, the text I'm reading doesn't indicate how these beverages were made, what they tasted like, what else went into them, or anything. But perhaps its source (Tello 1891) expands a little more on this topic. I bring this up because this is the first time I had ever heard of these beverages being consumed in Mesoamerica. When people talk about beverages they normally talk about a chocolate drink, pulque, chicha beer, or even atole. The fact that there are other beverages is a little surprising to me. And when I get back from visiting my parents over the holidays I am going to follow up on pre-Columbian beverages and these two in particular. In the meantime, if anyone is interested in pre-Columbian food I recommend taking a look at Sophie Coe's book America's First Cuisines (1994).

Baus de Czitrom, Carolyn. "The Tecuexes: Ethnohistory and Archaeology”." The Archaeology of West and Northwest Mesoamerica (1985): 93-117.

Tello, Antonio, Jaime de Rieza Gutiérrez, and José López-Portillo. Libro segundo de la Crónica miscelánea, en que se trata de la conquista espiritual y temporal de la Santa provincia de Xalisco en el Nuevo Reino de la Galicia y Nueva Vizcaya y descubrimiento del Nuevo México. No. 5311. " La República literaria," de CL de Guevara y ca, 1891.

In nineteenth century Chinese vernacular literature, the eating of vegetables had deeply ominous symbolism; during the Taiping Rebellion, writers across the empire fell back on familiar phrases to describe the carnage. In their stereotyped pattern, the deprivations of war forced people who had been eating grains to switch to vegetables, and then to wild plants, like leaves and tree bark, until finally they had to consume their own dead. This symbolized the breaking down of the social relations that held civilization together.

Tobie Meyer-Fong covers literary symbolism in What Remains: Coming to Terms with Civil War in 19th Century China

Among the natives of western North America, following acorns, the vegetable staple of most importance was camas (Camassia quamash) a relative of the asparagus but totally unlike it. This little bulb grew in profusion in the meadows of the far west and the rocky grassland/steppes of the Plateau and Great Basin. It was the plant that kept Lewis and Clarke's crew from starving after they abandoned their unsuccessful descent of the Snake River Canyon. Other desireable root plants were cowas (wild carrot) and balsam root. Balsam root grew much larger, but did not grow in profusion like camas did. If you are in the west in the spring, you may observe lower (wetter) areas of grasslands awash in a sea of blue camas blossoms.

Camas and other roots were collected in the spring and carefully dried. They were then ground into flour and baked into cakes. They can be eaten raw and are very pleasant tasting. Among the blue camas grew a white camas (not really camas) that was quite poisonous.

Can I ask a vegetable related question in this thread?

Why was it standard in the past to boil vegetables for so long?

Cookery books from the 40s & 50s often tell you to boil for 10 minutes or more, when nowadays half the time would be standard (aside from stuff like potatoes which do need longer cooking)

At a dinner, Beau Brummell was asked by his observant dinner partner, "Do you never eat vegetables?"

"Madame," he replied, "I once ate a pea."