In Chains, what one thing does Isabel take from Miss Finch's home in Rhode Island?

Isabel takes three things from Miss Finch's home.  She takes her blankets, her shoes, and some flower seeds that her mother had collected.  

Isabel's mother had collected the flower seeds and put them in a jar, but Isabel doesn't know what they will grow into.  

At this point in the story, Mr. Robert is taking Isabel and Ruth to be sold, but he allows the two girls to go back into the house...

Isabel takes three things from Miss Finch's home.  She takes her blankets, her shoes, and some flower seeds that her mother had collected.  

Isabel's mother had collected the flower seeds and put them in a jar, but Isabel doesn't know what they will grow into.  

At this point in the story, Mr. Robert is taking Isabel and Ruth to be sold, but he allows the two girls to go back into the house to collect their blankets and shoes.  He's not doing it to be nice either.  Having shoes and blankets will increase the slave value of Isabel and Ruth, and Mr. Robert is greedy.  Mr. Robert will not allow Isabel to take anything else, so she needs to grab something that is easily transported and easily hidden.  The seeds fill both of those requirements and have the added sentimental value of reminding Isabel of her mother.  

I looked around our small room, searching for a tiny piece of home I could hide in my pocket. 

What to take?

Seeds.

On the hearth stood the jar of flower seeds that Momma had collected, seeds she never had a chance to put into the ground. I didn't know what they'd grow into. I didn't know if they'd grow at all.  It was fanciful notion, but I uncorked the jar, snatched a handful, and buried it deep in my pocket just as the privy door creaked open.