Gillyweed

Gillyweed

Species information
Native range	Mediterranean Sea
Distinction(s)	When it is consumed, one grows gills and webbing between the fingers and toes.
Affiliation	Herbology; Plants

[Source]

Gillyweed is a magical plant native to the Mediterranean Sea. When it is eaten by a witch or wizard, one grows gills and webbing between the fingers and toes. There is some debate among Herbologists as to the duration of the effects of Gillyweed on fresh water versus salt water, ^[1] but the effects of Gillyweed in fresh water seem to last about an hour.

1 Description
2 Known Uses
3 Connection with Gillywater
4 Behind the scenes
5 Appearances
6 Notes and references

DescriptionEdit

Gillyweed is said to resemble a bundle of slimy, grey-green rat tails.

Known UsesEdit

Harry Potter used Gillyweed during the Second Task of the 1994 Triwizard Tournament. Dobby gave it to him, after overhearing a conversation which Barty Crouch Jr, disguised as Alastor Moody, staged with Professor McGonagall.

Connection with GillywaterEdit

Gillyweed can also, presumably, be used as an ingredient in a drink called Gillywater. Professor McGonagall once ordered a glass of it in The Three Broomsticks. Romilda Vane offered Harry a glass of Gillywater spiked with a Love Potion in an attempt to get Harry to ask her to Professor Slughorn's Christmas Party.

Behind the scenesEdit

Chocolate Frog Cards reveal that Gillyweed's properties were first discovered by Elladora Ketteridge but credited to Beaumont Marjoribanks about a century later.
Gillyweed is featured in Magical Water Plants of the Mediterranean and Magical Water Plants of the Highland Lochs, books lent to Neville Longbottom by Barty Crouch Jr., who was posing as Alastor Moody.
In the film, Neville Longbottom tells Harry about Gillyweed (he learned of it in a book Moody had given him), and is given the actual Gillyweed by Neville and told to put it in his mouth by Crouch/Moody.
In the book, it is Dobby who tells about and gives Harry the Gillyweed, after overhearing Moody/Barty's staged conversation with Professor McGonagall about which tactic the Champions might use in the Second Task.
There seems to be some Gillyweed stored in the Herbology Greenhouses as well as Professor Snape's private potion stores.^[2]