So, I've already read "The Cactus" by O. Henry for several times. And I'm really impressed! The story has an interesting plot with unexpected ending. I advise you to read this short story.You can find it here http://classiclit.about.com/library/bl-etexts/ohenry/bl-ohenry-cactus.htmFirst of all I want to give you some information about the author. I'll give you only interesting facts from his life. And then I'm going to proceed to the analysis.

 O. Henry was an American writer whose short stories are known for wit, wordplay and clever twist endings. He wrote nearly 600 stories about life in America.

He was born in Greensboro, N.C. He loved New York and many of his stories are set in the City.

William Porter only went to school until he was 15 years old. He dropped out of school as he could work at his uncle’s drugstore. 

In his 20 Porter became both a clerk and bank teller and moved to Texas. Then he was sent to jail not only for embezzlement, but also for absconding instead of facing trial. He had very little to say for his defense, still mourning the loss of his wife Athol, who died a few months before his trial. 

While in prison he began writing short stories in order to support his young daughter Margaret. His first published story was "Whistling Dick's Christmas Stocking" (1899). He used a pseudonym, Olivier Henry, only once and changed his pen name to O. Henry, not wanting his readers to know he was in jail. 

Porter gave various explanations for the origin of his pen name. In 1909 he gave an interview to The New York Times, in which he gave an account of it:It was during these New Orleans days that I adopted my pen name of O. Henry. I said to a friend: "I'm going to send out some stuff. I don't know if it amounts to much, so I want to get a literary alias. Help me pick out a good one." He suggested that we get a newspaper and pick a name from the first list of notables that we found in it. In the society columns we found the account of a fashionable ball. "Here we have our notables," said he. We looked down the list and my eye lighted on the name Henry, "That'll do for a last name," said I. "Now for a first name. I want something short. None of your three-syllable names for me." "Why don’t you use a plain initial letter, then?" asked my friend. "Good," said I, "O is about the easiest letter written, and O it is."A newspaper once wrote and asked me what the O stands for. I replied, "O stands for Olivier, the French for Oliver." And several of my stories accordingly appeared in that paper under the name Olivier Henry.