There are four sorts of tree; the first totally withered, to which the Pagans may be likened; the second, green but unfruitful, as the hypocrites; the third, green and fruitful, but poisonous, such are heretics; the fourth, green and bringing forth good fruit, to which are like the good Catholics.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).