type of willow, tamarisk
檉 refers to a specific type of willow or tamarisk tree, a plant known for its slender branches and often found near water.
檉 is a phono-semantic compound: 木 (tree) suggests the meaning, while 聖 likely contributes the sound. The exact historical development is uncertain, but the structure is typical for plant names.
The tree radical 木 beside 聖 (holy) can be remembered as a sacred willow or tamarisk planted near a shrine.
For テイ, picture a tea (ティー) party under the willow tree: tea -> テイ, and the willow's branches shade the table.
Tamarix chinensis; Chinese tamarisk