Gillyweed is a rather rare herb native to the Mediterranean Sea, and grows to a height of five centimeters to seven centimeters in soil with a pH range of 7.9–8.4 (Moderately alkaline). Gillyweed consumes a large amount of water, but requires little sunlight in order to thrive. Many weeds in the family of giliac weeds are this way; they need little sunlight, but have no limit to how much they'll take in as long as they have the water which they need. The Gillyweed is a slimy plant, grows as in bushel, and is grey-green in color.
Consumption of Gillyweed by a fully human being results in temporary growth of gills and webs between toes and fingers. The effect lasts for about an hour in fresh water and up to three hours in salt water (although, there is some controversy around this in the field of Herbologists. Several suggested that the salt water number is not accurate, and many contest the difference of the effects of Gillyweed between salt and fresh water). The properties of Gillyweed include a refreshed, nourishing feeling when it is consumed, thus making Gillywater a popular drink. Gillywood is a tree which grows in water, and is believed to be a relation to the Gillyweed due to the patterns in its leaves.

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How to make Gillywater:

Begin with either a pure water, or a juice. You will need a cucumber, as well as several sheaves of Gillyweed. Peel the cucumber, then cut it into long, relatively thin strips. Use the longest to tie the rest of the strips together. Pour whichever liquid you choose into the cup, and then add the cucumber. The longer you let sit, the stronger the cucumber taste. Right before drinking, add Gillyweed to the cup, and perhaps a chilling charm or ice cubes. Gillyflower may also be added if you like a little spice in your drink.