Q:
A plant that was given to me as a cutting has clear beads at irregular intervals along the stem. They are firm rather than sticky, but can be mashed between thumbnails. Is this insect- or disease-related, or something else? (The plant may be Abutilon but it has not flowered yet, so I am not sure.)
A: It is possible that these are "
pearl bodies," also called "pearl glands" or — if seen on grapes — "grape balls." According to
this scientific article, they are a type of food body (a nutrient-dense plant structure that offers food rewards to creatures such as ants). Other types of food bodies are extrafloral nectaries that secrete nectar, and domatia (chambers a plant produces to house ants or mites). Pearl bodies are part of a system of
mutualism between plant and arthropod: ants gather the pearl bodies and take them to their nests, prompting the plant to form new ones in their place; in return, the ants may defend the plants against insect pests. Pearl bodies may be found on many different plants, particularly on a plant’s most robust branches.
The Miller Library staff are pleased to welcome Renée Simard back for a virtual exhibit of her
