With the work of Emmeline Grangerford, Twain satirizes Gothic, Romantic literature. It is fair to say that Emmeline's subject matter suggests an obsession with death and borders on the macabre, not unlike the work of Edgar Allan Poe. The poem "Ode to Stephen Dowling Bots, Dec'd" can be read as a parody of Poe's works "Annabel Lee" and "The Raven." There is dark humor to be found in Emmeline's ode to a boy who died from falling down a well. Her verse is overwrought, and Huck's naivete in describing her talent allows Twain's mockery to emerge:

She warn't particular, she could write about anything you choose to give her to write about, just so it was sadful. Every time a man died, or a woman died, or a child died, she would be on hand with her "tribute" before he was cold.

Huck's description of Emmeline's drawings is equally humorous. The unfinished work that hangs above her bed and that is covered by a set of curtains except on her birthday was thought by the family to be "her greatest picture":

It was a picture of a young woman in a long white gown, standing on the rail of a bridge all ready to jump off, with her hair all down her back, and looking up to the moon, with tears running down her face, and she had two arms folded folded across her breast, and two arms stretched out in front, and two more reaching up towards the moon—and the idea was, to see which pair would look best and then scratch out all the other arms . . . .

Huck comments that "there was so many arms it made her look too spidery, seemed to me." Huck also comments that her work gave him "the fan-tods" and that "with her disposition, she was having a better time in the graveyard."

In this humorous episode, Twain satirizes the excessive emotion present in the work of the Romantics. Huck's pragmatic and unaffected description of the work delivers the message that he, and the author, prefer the unadorned style of Realism.

Basically, the late Emmeline Grangerford's art and poetry was all completely morbid and sad.  As Huck says about her poetry,

she could write about anything you choose to give her to write about just so it was sadful.

All of her pictures are of dead or dying things.  She has one of a woman mourning at a grave.  She has one of a woman mourning a dead bird.  The one she was working on when she died was a woman about to commit suicide.  Her poetry was also about dead people.

Huck says that he thinks all of her work is nice but that he can't "take to it.  It is all too sad and it depresses him to see any of it.

You can find more details in Chapter 17.