A dryad (or wood nymph) is a female spirit often associated with a certain tree.
In Greek mythology, a dryad is usually a female spirit typically associated with a particular location or land form. Other nymphs, always in the shape of young maidens, were part of the retinue of a god, such as Dionysus, Hermes, or Pan, or a goddess, generally Artemis. They are beautiful humanoids with elf-like appearance and can sometimes be seen with tree-like appendages and sometimes be green. They live in groves, in trees and in valleys and cool grottoes. All dryads are born with a certain tree over which they will watch. A dryad either lives in a tree, in which case she is called a Hamadryad, or close to it. The life of dryad is connected with that of a tree. That is, the longer the tree lives, the longer the dryad does. If the death of a dryad is caused by a mortal, the gods will punish him/her. The dryad itself will punish any mortal who tries to hurt its tree. The nymphs at Camp Half-Blood act as waitresses at mealtimes.
Luke summons a pit scorpion to kill Percy. When it gets Percy, Percy tries to get back to camp, but he is dying. Luckily, some wood nymphs carry him to the Big House. They are unnamed, but they did save his life.
Grover and Percy watch a satyr chase a redheaded nymph until she goes into tree form and the satyr kisses her as she transforms herself into a tree. Grover sees this as perfectly normal.
- Juniper- Grover's girlfriend, a dryad, and lives in a Juniper tree. Grover is said to once have had a crush on a wood nymph that lived inside a blueberry bush. There have been references to her having green tears appearing similar to or the same as the chlorophyll present in plants. Juniper also appears to have the ability to disappear in a puff of green mist, and it is unclear whether this ability is present in all wood nymphs.
- In the series, dryads are nymphs of individual trees, while in Greek mythology, a dryad was said to be the nymph of an entire forest or grove of trees. Hamadryads were the nymps of individual trees, and it was said that they rarely left their tree for any reason.
- Other nymphs related to the earth and woods are:
- Aigeroi: Nymphs of black poplars
- Ameploi: Nymphs of grape vines
- Anthousai: Flower nymphs and a type of Oceanid
- Balanis: Acorn and ilex nymphs
- Daphnaie: Laurel nymphs
- Hamadryades: Dryads of oak and poplar trees
- Karyai: Nymphs of hazel-nut trees
- Kraneiai: Nymphs of cherry trees
- Mailiades (Epimelides): Nymphs of apple and other fruit trees, highland pasture; the protectors of sheep. They were perhaps numbered among the Oceanids as well.
- Meliae: Nymphs of honey, bees, beekeeping. They were also dryads of the mountain ash.
- Moreai: Nymphs of mulberry trees
- Orieades: Nymphs of the mountains oaks and pines
- Pteleai: Elm Nymphs
- Sykei: Fig Nymphs
- Anthousai: Flowers
|Species:||Centaur | Cyclopes | Dragon | Drakon | Empousa | Fire-Breathing Horse | Giants | Gorgon | Harpy | Hyperborean Giant | Ichthyocentaur ||
|Friendly Monsters:||Argus | Blackjack | Briares | Chiron | Don | Ella | Festus | Gleeson Hedge | Gray |Grover Underwood | Hippocampus | Mellie | Mrs. O'Leary | Ophiotaurus | Peleus | Scipio | Tyson | Tempest|
|Enemy Monsters:||Agrius and Oreius | Arachne | Basilisk | Charybdis and Scylla | Chimera | Chrysaor | Clazmonian Sow | Colchis Bull | Echidna | Euryale | Geryon | Joe Bob | Kampê | | Nanette | Manticore | Medusa | Minotaur | Nemean Lion | Polyphemus | Sphinx | Stheno | Typhon | Scythian Dracanae|
|Neutral Monsters:||Carnivorous Sheep | Cerberus | Erymanthian Boar | Gray Sisters | Gorgons | Furies | Flesh-Eating Horse | Gryphon | Siren|