Stem
When you leave flowers on a tombstone they look good at first, but after a few days or some harsh weather, there's nothing left but stems. That's why you have to replace flowers on tombstones all the time. If you don't it will look like you only left the stems there, and that's pretty disrespectful.
Imagine being in a graveyard looking at all the tombstones and seeing nothing but stems on all of them. All the pretty flowery parts have died and blown away.
きょう, けい
くき
None
You have an idea that can make these tombstones look better than just having leftover stems all over them. You brought cookies (くき)! Cookies don't fall apart in the wind, and everyone loves cookies, alive or dead. You replace the stems with the cookies and everything looks a lot nicer.
Look at all the cookie covered tombstones. Now your bag is full of stems, but you can use them to make more cookies to bring back next time. Don't worry, nobody eats them. Stem cookies are probably poisonous.