The requirement to have a meal jointly owned by the residents of the courtyard who need to create a group eiruv leads the Gemara to bring the opinions of sages who discuss what is considered food that will live up to this condition.
Rabbi Yehuda said in the name of R’ Shmuel bar Sheilat, who said in the name of Rav: One may establish an eiruv with cheap and unimportant produce such as cress, purslane, and sweet clover, but one may not establish an eiruv with green grain or with unripe dates.
Ḥalaglogot appear to be Portulaca oleracea, or common purslane, an annual plant that grows close to the ground and spreads out on fields. It grows mainly during the summer months in Israel and nearby countries. It is gathered for food and can be eaten fresh or pickled – sometimes it is even grown specifically for that purpose.
According to most of the early commentators, gudgedaniyyot can be identified as one of the melilotus, or sweet clover plants. These wild plants grow tall and have pods that contain one or two seeds. Generally speaking they are used to feed animals, but they are certainly fit for human consumption. In the past it was also used for medicinal purposes; the Gemara suggests that it was known as a prophylactic.
Ḥaziz (green grain) is a general term for the green parts of various types of grain that are mainly used as animal fodder.
Kafniyot are wild dates that do not ripen properly.
Another plant that cannot be used for the eiruv is a kor. The kor (heart of palm) refers to the top of the stem of the palm. Although it is not fruit, as it is part of the tree itself, it is edible – the inner section of the trunk top is white and tasty and is considered something of a delicacy. In the time of the Talmud heart of palm was eaten both boiled and fried. Since removing the kor from the palm tree had the effect of preventing future growth and development of the tree, it was only cut off from a date palm that they decided to cut down.
Rav Ḥilkiya bar Toviya said: One may establish an eiruv with glasswort. The Gemara expresses astonishment: Does it enter your mind that one may establish an eiruv with glasswort? People do not eat glasswort. Rather, one may establish an eiruv with the herb from whose ashes glasswort is prepared, as it is fit for human consumption before it is burnt.
The kalya is identified as the Salicornia europaea or Common Glasswort which has pods but no leaves. It grows wild to a height of 10 – 14 centimeters in swampy areas. The ashes of this plant contain a high concentration of potassium, which was used to produce soap and clothing detergent. As an edible plant, it was, however, also used for food.