26814
It gets its name from the hackberry tree ( " Celtis occidentalis " and others in the genus " Celtis " ) upon which it lays its eggs .
 Celtis occidentalis
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 Celtis occidentalis