In 1867 Schwendener announced to the scientific world his hypothesis that lichen was formed by two separate organisms, a fungus and an alga. At the time his theory was largely rejected, but it was afterwards proven to be factual.
And because I observed, besides, that an inquiry of this kind was of all others of the greatest moment, and one in which precipitancy and anticipation in judgment were most to be dreaded, I thought that I ought not to approach it till I had reached a more mature age, (being at that time but twenty-three,) and had first of all employed much of my time in preparation for the work, as well by eradicating from my mind all the erroneous opinions I had up to that moment accepted, as by amassing variety of experience to afford materials for my reasonings, and by continually exercising myself in my chosen Method with a view to increased skill in its application.
Simon Schwendener (Wikipedia) Simon Schwendener (10 February 1829 – 27 May 1919) was a Swiss botanist who was a native of Buchs in the Canton of St. Gallen.