Are there ways to identify a web element in R when CSS is not used?

I want in R to download the data I get from the following website by clicking the "Download" button on the right.

http://ift.tt/1MxxfWz

I wanted to do it with RSelenium and use SelectorGadget to find the CSS of the button. However, the button has no CSS. Are there ways to do what I want in R?

Usually I would do it like in the code below but this needs a CSS.

library("RSelenium")

startServer()
#checkForServer()

mybrowser <- remoteDriver()
mybrowser$open()

mybrowser$navigate("http://ift.tt/1MxxfWz")

wxbutton <- mybrowser$findElement(using = 'css selector', "????????")
wxbutton$clickElement()