Task: Text Simplification
Input (English): wahlenbergia species have dispersed widely , even to oceanic islands , and there are four species known from the island of st helena , including the now extinct species w. roxburghii.
Output (English): the wahlenbergia species have spread out far and wide including some oceanic islands and the island of st helena contains all four specii and also the presently-extinct one , w. roxburgh.