The Latin verb discurrere meant "to run about", and from this word we get our word discursive , which often means rambling about over a wide range of topics. A discursive writing style generally isn't encouraged by writing teachers. But some of the great 19th-century writers, such as Charles Lamb and Thomas de Quincey, show that the discursive essay, especially when gracefully written and somewhat personal in tone, can be a pleasure to read. And the man often called the inventor of the essay, the great Michel de Montaigne, might touch on dozens of different topics in the course of a long discursive essay.
Descriptive writing is something which focuses more on the details and physicality of whatever is under discussion. Because of this, the structure of the essay is generally seen as being less rigid than other essays, although it does still follow the basic structure of introduction, three to five body paragraphs, and conclusion. Descriptive essays need to consider their audience very carefully, as this will determine the type of language that is used, as well as how the essay itself is written. Descriptive essays can be written in chronological order, but the type of essay means that they are usually arranged spatially, with lyric essays being a very good example of the format.