What is the name for a group of achenes or drupels? It begins with
'e'. Answer needed by 11 August.

I believe the word you're seeking is "etaerio."

"etaerio...
noun  an aggregate fruit, as one consisting of drupes (raspberry) or
achenes (traveller's joy)
[ETYMOLOGY: 19th Century: from French etairion, from Greek hetaireia association]" 

Word Reference: etaerio
http://www.wordreference.com/definition/etaerio.htm

"etaerio (Gr. etaireia: association of friends) n. A cluster of fruits
formed from the unfused carpels of a single flower. For example, the
anemone has an etaerio of achenes, larkspur an etaerio of follicles,
and blackberry an etaerio of drupes."

Université du Québec à Montréal: Botanical Terms
http://www.info.uqam.ca/~fg/e.botanicalTerms.html

Google search strategy:

Google Web Search: "etaerio" + "achenes"
://www.google.com/search?hl=en&ie=UTF-8&q=etaerio+achenes

If this is nor the correct word, please request clarification; I'll be
glad to offer further assistance before you rate my answer.

Best regards,
pinkfreud

Excellen quick response - thank you