D needs to be for something...

"D needs to be for something," Uncle Mac proclaimed dolefully, "or we'll be out of the A to Z bloggery challenge before you can say 'diplodocus'."

"Why would we say such a thing?" asked Farm Girl, reasonably, "the word's a trifle oddicus." 

"Besides, I think it's diplo-dough-cus, the last part seems to rhyme with "focus".

Mallory leaped to his feet.

"His brain's no bigger than a pea, his appetites humongous!"
"He's eminently qualified to hold a seat in congress!"

"NO!", thundered Uncle M, thunderously, "there will be no diplodochian doggerel today. No sauropodian sonnets. No reptilian rhymes. We are gardeners, not paleontologists and certainly not poets. Our readers deserve better from us."

"No they don't, I've met a few of them." contributed Delacroix. "How about some prehistoric pentameter?"

Aunt Agnes chose this moment to sidle in through the south or garden side doorway.

"Or maybe ding-bat?", murmured Farm Girl, "or dyspeptic disgrace?"

"Dill?", suggested the Disgrace.

"Dill! Not bad! Used for pickling and seasoning, a herb of some merit!", Uncle M seemed genuinely enthused.

DILL

"A relative of carrots and very easy to grow."

A prolonged silence settled over the group.

"Tomorrow's another day", observed Farm Girl, "Perhaps we'll do better with E."

"Let's hope so.", said Uncle Mac.