Hawthorn

There is a lot of hawthorn growing alongside the canal. Here is a close up of some. I didn't realise it has medicinal uses (until I looked up Wikipedia):

Crataegus monogyna is one of the most common species used as the "hawthorn" of traditional herbalism, which is of considerable interest for treating cardiac insufficiency by evidence-based medicine. The plant parts used medicinally are usually sprigs with both leaves and flowers, or alternatively the fruit. Several species of Crataegus have both traditional and modern medicinal uses. It is a good source of antioxidant phytochemicals, especially extracts of hawthorn leaves with flowers.

So now you know!